Strange new 'species' of ultra-red galaxy discovered

Dec 01, 2011
This artist's conception portrays four extremely red galaxies that lie almost 13 billion light-years from Earth. Discovered using the Spitzer Space Telescope, these galaxies appear to be physically associated and may be interacting. One galaxy shows signs of an active galactic nucleus, shown here as twin jets streaming out from a central black hole. Credit: David A. Aguilar (CfA)

In the distant reaches of the universe, almost 13 billion light-years from Earth, a strange species of galaxy lay hidden. Cloaked in dust and dimmed by the intervening distance, even the Hubble Space Telescope couldn't spy it. It took the revealing power of NASA's Spitzer Space Telescope to uncover not one, but four remarkably red galaxies. And while astronomers can describe the members of this new "species," they can't explain what makes them so ruddy.

"We've had to go to extremes to get the models to match our observations," said Jiasheng Huang of the Harvard-Smithsonian Center for Astrophysics (CfA). Huang is lead author on the paper announcing the find, which was published online by the .

Spitzer succeeded where Hubble failed because Spitzer is sensitive to infrared light - light so red that it lies beyond the visible part of the spectrum. The newfound galaxies are more than 60 times brighter in the infrared than they are at the reddest colors Hubble can detect.

Galaxies can be very red for several reasons. They might be very dusty. They might contain many old, red stars. Or they might be very distant, in which case the stretches their light to longer wavelengths and hence redder colors (a process known as redshifting). All three reasons seem to apply to the newfound galaxies.

All four galaxies are grouped near each other and appear to be physically associated, rather than being a chance line-up. Due to their great distance, we see them as they were only a billion years after the Big Bang - an era when the first galaxies formed.

"Hubble has shown us some of the first protogalaxies that formed, but nothing that looks like this. In a sense, these galaxies might be a 'missing link' in " said co-author Giovanni Fazio of the CfA.

Next, researchers hope to measure an accurate for the galaxies, which will require more powerful instruments like the Large Millimeter Telescope or Atacama Large Millimeter Array. They also plan to search for more examples of this new "species" of extremely red galaxies.

"There's evidence for others in other regions of the sky. We'll analyze more Spitzer and Hubble observations to track them down," said Fazio.

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Vendicar_Decarian
1.9 / 5 (8) Dec 01, 2011
What is the value of the fine constant in that area of the early universe?
Callippo
1.4 / 5 (9) Dec 01, 2011
Well, this is the right question. The fine structure constant is a running constant, and thus isn't actually constant, see for example the NIST web, where you can read:

"...Thus (value of) alpha depends upon the energy at which it is measured, increasing with increasing energy, and is considered an effective or running coupling constant. Indeed, due to e e- and other vacuum polarization processes, at an energy corresponding to the mass of the W boson (approximately 81 GeV, equivalent to a distance of approximately 2 x 10-18 m), (mW) is approximately 1/128 compared with its zero-energy value of approximately 1/137. Thus the famous number 1/137 is not unique or especially fundamental... blah, blah..."

http://physics.ni...pha.html

So, if the universe was formed at the GUT energy, then the value of alpha should be zero, because all forces were equal that "time". We don't observe it, which introduces a problem for Big Bang theory.
Callippo
1.4 / 5 (10) Dec 01, 2011
The value of small structure constant basically says, how much the observable matter is transparent. In dense aether model the remote galaxies should appear larger and more transparent, because they behave like the objects disappearing in fog of vacuum density fluctuations, which are responsible for the red shift. We can consider it as one of many predictions of dense aether model.

http://www.aether...rchy.gif

The standard Big Bang model predict instead, due the expansion of space-time the remote galaxies should appear smaller. This hasn't been confirmed with observations, which are supporting dense aether model instead.

http://arxiv.org/abs/1011.4956
Isaacsname
5 / 5 (2) Dec 01, 2011
I've heard in lectures that the FSC in the case of something like an electron is just the self-energy of the particle squared, but that it basically represented the binding energy of the particle available in regards to the particle and the system it's part of. ,..this is true, or do I have it bass-ackwards..?

Aren't all constants derived from measurement just approximations with a shrinking degree of uncertainty in measurement ?
yyz
5 / 5 (3) Dec 01, 2011
"The standard Big Bang model predict instead, due the expansion of space-time the remote galaxies should appear smaller. This hasn't been confirmed with observations..."

This can be shown to be trivially false.

__________dimensions_____distance(Mly)

M 31......190'x60'........2.54
M 33......71'x42'.........2.7
M 81......27'x14'.........11.8
NGC 253...27.5'x7'........11.4

compared to ANY galaxy in the HUDF, HDF-N or HDF-S over a billion light years distant is well under 2 arcminutes in apparent diameter. Astronomers can see apparent size-distance differences *within* the galaxies sampled in the Hubble deepfields. More distant galaxies do appear smaller than nearby galaxies.

This most definitely has been confirmed with *many* observations(eg): http://arxiv.org/...33v1.pdf
that_guy
4.5 / 5 (6) Dec 01, 2011
Spitzer succeeded where Hubble failed because Spitzer is sensitive to infrared light - light so red that it lies beyond the visible part of the spectrum.


I've also found that ultra-violet is so violet that it lies beyond the visible part of the spectrum, and X-rays should be renamed ultra ultra violet, because they are so ultra violet that they lie beyond the ultra violet spectrum. and gamma rays should be called ultra ultra ultra violet.

If the article can't be comprehended by an elementary school student, they shouldn't bother using explanations you would tell an elementary student.

Look, we all understand that infrared light has a shorter wavelength than the visible spectrum and is just beyond our ability to see.
mattbroderick
4.6 / 5 (10) Dec 01, 2011
Look, we all understand that infrared light has a shorter wavelength than the visible spectrum and is just beyond our ability to see.


Maybe not all of us. Infrared has a LONGER wavelength. :)
that_guy
5 / 5 (3) Dec 01, 2011
@ callippo -

lay a balloon out flat and draw a smiley face on it. Next, stretch it out to twice its original size, and move it twenty feet away. This accounts for the expansion of space since the light from these galaxies was emmitted.

For things we can see, this effect is relatively small. However, the point is that anything we see will look proportionally larger, due to the fact that space has not been geometrically static in the last 10 billion years.

Theoretically, if you had a clear line of sight on galaxies going all the way to the big bang, they would eventually stop becoming smaller, and start becoming bigger and much fainter

Finally as this effect becomes substantially more pronounced, you get to the CMB, which is the light from a single tiny point spread all across the sky.

that_guy
5 / 5 (6) Dec 01, 2011
Look, we all understand that infrared light has a shorter wavelength than the visible spectrum and is just beyond our ability to see.


Maybe not all of us. Infrared has a LONGER wavelength. :)

LMAO. I was so involved in making a parody of the shorter wavelengths that it came out wrong when i got back to infrared.
Pirouette
3 / 5 (4) Dec 01, 2011
typo is forgiveable :/
joefarah
1 / 5 (1) Dec 01, 2011
OK. I have a simple problem - can someone help?
If the light from the galaxies is 13B ly, only 1B from the big bang, why do we not see light on the other side of the big bang? Theoretically, there should be another 13B ly of galaxies on the other side of the big bang. Either that or the big bang was only 7B ly away from us.
cyberCMDR
4 / 5 (4) Dec 02, 2011
@joefarah: If time started at the big bang, light from farther away than 13.7 billion light years would not have had the time to reach us by definition.
Hengine
5 / 5 (6) Dec 02, 2011
Cannot wait for JWST!!!
jsdarkdestruction
4 / 5 (4) Dec 02, 2011
Cannot wait for JWST!!!

right on, i cant either. Just think of the possibilities.....breathtaking really. sadly it doesnt look like it will be going up as soon as originally planned as last i heard they were aiming for something like 2018 for launch and with nasa the way they are we can probably expect more like 2020, if the project isnt somehow killed by the republicans before then.
Callippo
1 / 5 (9) Dec 02, 2011
JWST will never start. Find a better toy, guys..
Vendicar_Decarian
3.7 / 5 (6) Dec 02, 2011
Incorrect.

"Finally as this effect becomes substantially more pronounced, you get to the CMB, which is the light from a single tiny point spread all across the sky." - That guy

The CBR comes from a time well beyond the singularity when the universe made a transition from a radio-opaque plasma to a radio-transparent diffuse neutral gas.

Plasma's eat EM Radiation.

Vendicar_Decarian
3 / 5 (4) Dec 02, 2011
"Either that or the big bang was only 7B ly away from us." - jfarah

The BB theory does not require the universe to be any particular size and in fact it may be infinite in extent. However we can only observe out to 13 billion light years in any direction.

Rather than thinking of universe as a some kind of bag, consider that it is infinite in extent and that the ruler you are using to measure size is shrinking.

Because your ruler is shrinking you see distant objects as moving away from you.

Because your ruler is shrinking you see the light that they emitted apparently getting longer in wavelength and hence redder.

Because your ruler is shrinking in length you see that the farther an object is from you the faster it seems to move away.

Now consider the universe evolving backward in time. Your ruler gets longer and longer , things appear to get closer and closer until eventually things begin to overlap and merge, the entire universe will eventually overlap and every ruler cont
Vendicar_Decarian
3.5 / 5 (6) Dec 02, 2011
will span the entire infinite universe.

That is the singularity from which the universe evolved from.

However there is a complication. Time slows down as the energy density of the space it is moving through increases. So the closer you get to the singularity the longer it takes to get there.

As a result, there is no beginning. Just an infinite trend to infinite energy density.

From this perspective, there is no other side.
_ilbud
5 / 5 (1) Dec 02, 2011
Zeno's bang
brodix
2.1 / 5 (7) Dec 02, 2011
If in fact redshift is an optical effect, then this is exactly what we will find, ever more distant galaxies, redshifted completely off the visible spectrum.
http://www.americ...folktale
brodix
1 / 5 (2) Dec 02, 2011
When light is gravitationally lensed, it doesn't mean the source of that light is moving about, or being split into holographic copies, just that the path of the light is being distorted. Since gravitational contraction and spatial expansion are inversely proportional, doesn't that suggest there is an opposite lensing effect going on here and that there is a cosmic lensing effect causing redshift? It would explain why it is proportional to distance. The black body radiation would be residual light that has shifted completely off the visible spectrum and we will continue to find ever fainter and further redshifted galaxies.
antialias_physorg
3 / 5 (2) Dec 02, 2011
If the light from the galaxies is 13B ly, only 1B from the big bang, why do we not see light on the other side of the big bang?
Because the big bang was not an explosion at one point in space, but rather the start of the expansion of space (i.e. at the big bang event all space was inthe same 'place')

So really every position in space today IS the place where the big bang happened. This is why we see the remnant radiation from that event (cosmic microwave background) coming from all directions. If it had been an explosion INTO space we'd only see it come from one direction.

Also the event was the beginning of what we call spacetime. So you can't really look further back because there is no 'further back' in time.
that_guy
5 / 5 (1) Dec 02, 2011
Incorrect.

"Finally as this effect becomes substantially more pronounced, you get to the CMB, which is the light from a single tiny point spread all across the sky." - That guy

The CBR comes from a time well beyond the singularity when the universe made a transition from a radio-opaque plasma to a radio-transparent diffuse neutral gas.

Plasma's eat EM Radiation.


Fair enough. The CMB spans the entire sky even though it comes from a much smaller area than it now appears to occupy - still working as an example of my point above. But corrected now, as vendicar pointed out.
Benni
1.2 / 5 (6) Dec 02, 2011
Because the big bang was not an explosion at one point in space, but rather the start of the expansion of space (i.e. at the big bang event all space was inthe same 'place')

So really every position in space today IS the place where the big bang happened. This is why we see the remnant radiation from that event (cosmic microwave background) coming from all directions. If it had been an explosion INTO space we'd only see it come from one direction.

Also the event was the beginning of what we call spacetime. So you can't really look further back because there is no 'further back' in time.

I faithfully watch the History & Science channels "Universe" presentations. Their animations always show a "bang" (the focal point) from a massive single object from which all else originated as that explosion expanded & pushed stellar matter into the vacuous space around it. I don't understand how your post comports with commonly held "big bang" animations?
lomed
4.5 / 5 (4) Dec 02, 2011
Their animations always show a "bang" (the focal point) from a massive single object from which all else originated as that explosion expanded & pushed stellar matter into the vacuous space around it. I don't understand how your post comports with commonly held "big bang" animations?
Those animations are conceptually (among other ways) inaccurate. Usually people that study the universe look at it as if the cosmic microwave background (CMB) radiation were stationary and all emitted at the same instant. In this frame of reference the change in distance between two superclusters of galaxies is almost entirely due to the expansion of the space between them and not due to their motion relative to the CMB. Following these effects backwards, one finds that everything in the observable universe would have been at the same point around 13.7 billion years ago.
brodix
1 / 5 (1) Dec 02, 2011
If all of space expanded from that one point, why is there a stable speed of light?
Example: If two galaxies are x lightyears apart and the universe doubled in size, then they would be 2x lightyears apart. So what determines that otherwise stable speed of light, if the very space it is measuring is expanding? That is not expanding space, but an increasing amount of stable space. So either we are at the exact center of the universe, or redshift is an optical effect, proportional to distance.
And that is why we will keep finding the signatures of ever more distant galaxies hidden in that background radiation.
lomed
5 / 5 (1) Dec 02, 2011
So what determines that otherwise stable speed of light, if the very space it is measuring is expanding?
Systems that are bound together by some force (usually gravity on large scales) do not expand. It is only the distance between unbound systems that expands. Superclusters of galaxies are just about the largest systems that are bound, everything more distant than about 200 million light-years (and many things less distant) is increasing in distance mostly due to the expansion of space. So, while on Earth one can measure the speed of light without having to take into account the expansion of space, the same is not true for distances over a few hundred million light-years. Over such large distances, the light travel time is only one way of talking about the distance (see the wikipedia article on "Distance measures (cosmology)").
Benni
1 / 5 (2) Dec 03, 2011
Following these effects backwards, one finds that everything in the observable universe would have been at the same point around 13.7 billion years ago.

I'm really trying hard to follow you here. Your statement "everything in the observable universe would have been at the same point around 13.7 billion years ago". This sounds exactly like a massive concentration of mass just as BB hypotheses states, yet you say such is "conceptually inaccurate". What is it that is conceptually inaccurate? The BB or what? It is crystal clear what message the animations wish to convey. Something is missing here.
Vendicar_Decarian
3 / 5 (2) Dec 03, 2011
"I don't understand how your post comports with commonly held "big bang" animations?" - Benni

Their animations are misrepresentations based on ignorance of what is thought to have happened.

The real theory is more esoteric and more difficult to depict and explain.
Vendicar_Decarian
1 / 5 (1) Dec 03, 2011
"So what determines that otherwise stable speed of light" - Brodix

Good question. To a great extent the "stable" speed of light is just assumed.

So far no one has found any reason to question that assumption. Until that is... Until the universe becomes very energy dense. And then c becomes smaller and in the limit zero.

Vendicar_Decarian
3 / 5 (2) Dec 03, 2011
"And that is why we will keep finding the signatures of ever more distant galaxies hidden in that background radiation." - Brodix

So far there are no significant anomalies seen in the most distant galaxies, although there is some surprise that they managed to organize so early, and that some stars in them appear to be older than easily accounted for.

But there isn't sufficient evidence to say that anything has upset the BB theory, and there is substantial confirming evidence. For example, the structure of early galaxies is what is expected of galaxies early in their formation. Most of the stars are young, which is expected. Three are lots of active galactic nuclei which is what we expect with a higher density of interacting galaxies, etc.
bluehigh
1 / 5 (7) Dec 03, 2011
And then c becomes smaller and in the limit zero.


The Light of other days?

bluehigh
1 / 5 (12) Dec 03, 2011
But there isn't sufficient evidence to say that anything has upset the BB theory


We could start with that its illogical, defies commonsense, creates paradoxes, is hardly any different to the Biblical 'Creation' and is mostly a matter of belief rather than science.
Vendicar_Decarian
4 / 5 (8) Dec 03, 2011
"This sounds exactly like a massive concentration of mass just as BB hypotheses states, yet you say such is "conceptually inaccurate". What is it that is conceptually inaccurate? " - Benni

What is inaccurate is your perception of how all matter is condensed to a very small volume. It is, but then so is all of space, and that is the part you aren't getting.

Space itself contracts to the same point. There is no looking from the outside at the exploding universe, as there is no outside, since there is no space there.

It's not a bag, or a balloon, and it isn't an explosion as you know it, since there is nothing for the matter to explode into. neither is it necessarily finite, a universe that is infinite in extent might exist at the original singularity.

The graphics that depict the BB as an explosion do so out of ignorance and laziness. There was no explosion per say.

I described earlier the correct view, where the universe - possibly one of infinite extent, starts Cont.
Vendicar_Decarian
4 / 5 (8) Dec 03, 2011
with an infinite energy density. Rulers then begin to shrink and the universe appears to cool and expand.
Vendicar_Decarian
4.3 / 5 (11) Dec 03, 2011
"We could start with that its illogical, defies commonsense, creates paradoxes," - BlueHigh

The same can be said for the invariability of c. But there it is... Staring you in the face... Reality has no reason to conform to your view of how things should be.

If you don't like this universe, find yourself another one in which to live.

omatumr
1 / 5 (8) Dec 03, 2011
ultra-red galaxy


This title suggests that observer are looking at energy that is far away from its source.

Why? Energy is stored as rest mass and usually released in radiation of extremely short wave length, e.g., gamma rays.

The natural sequence of events is usually like this:

Rest mass => Gamma rays => X-rays =>
UV-radiation => Visible-light => IR

With kind regards,
Oliver K. Manuel
Former NASA Principal
Investigator for Apollo
http://myprofile....anuelo09
TimLong2001
not rated yet Dec 03, 2011
Do a search for "photon structure" or "wave particle duality photon" and check out Photon Structure for a different slant on the red shift. Hubble himself did NOT say the universe was expanding. This was promoted by others.
lomed
not rated yet Dec 03, 2011
This sounds exactly like a massive concentration of mass just as BB hypotheses states, yet you say such is "conceptually inaccurate". What is it that is conceptually inaccurate?
Sorry, I see I wasn't entirely clear as to what, specifically, is conceptually inaccurate. It is conceptually inaccurate to depict having been able to observe matter exploding out from a central point. Any observer must exist within space, as one goes further back in time the distances between objects decrease no matter what the vantage point. So, at every point matter gets denser and thus hotter. In short, there is nowhere from which one could have an outside vantage point because the big bang literally happened everywhere.

If one follows the conditions at any given point in the universe back in time it will eventually be very hot and very dense there. There is no outside of space from which one could watch the universe expand and cool as opposed to the case of an explosion.
brodix
1 / 5 (2) Dec 03, 2011
Systems that are bound together by some force (usually gravity on large scales) do not expand. It is only the distance between unbound systems that expands. Superclusters of galaxies are just about the largest systems that are bound, everything more distant than about 200 million light-years (and many things less distant) is increasing in distance mostly due to the expansion of space. So, while on Earth one can measure the speed of light without having to take into account the expansion of space, the same is not true for distances over a few hundred million light-years. Over such large distances, the light travel time is only one way of talking about the distance (see the wikipedia article on "Distance measures (cosmology)").

When all space was originally contained in a much smaller universe, were galaxy clusters still hundreds of millions of lightyears apart, but the light simply traveled slower, or is there a stable speed of light, so it took light less travel time?
BillFox
not rated yet Dec 03, 2011
The viewpoint of the BB that is depicted in these animations is from a point in space that did not exist at that moment.
brodix
1 / 5 (2) Dec 03, 2011
Most of the stars are young, which is expected.

Vendicar,
As I've understood it, those distant galaxies are considered young because the light only comes from the lightest elements(hydrogen, helium..) and therefore starts at the blue end of the spectrum. It occurs to me, that as the light is redshifted, the red end of the spectrum would be the first to fall off the visible scale and eventually we would only see what had started on the blue end, as the last visible light. So we would not be able to tell if these very distant galaxies had light from heavier elements, unless we fully examine the black body radiation around them. In that regard, it would be interesting to take the methods of observation mentioned in this article and apply them to what we consider those distant, young galaxies and see if there are not signatures of heavier elements hiding in them.
lomed
not rated yet Dec 03, 2011
When all space was originally contained in a much smaller universe, were galaxy clusters still hundreds of millions of lightyears apart, but the light simply traveled slower, or is there a stable speed of light, so it took light less travel time?
It took light less time.

The speed of light (in a vacuum) is a constant and equal to that measured near Earth over any region of space or time that is small compared to its curvature (which is produced by mechanical stress, mass, and energy). If something with non-zero rest mass follows a given path then it takes more time to do so than would a light beam following the same path in a vacuum.

General relativity is constructed so that the laws of physics are the same everywhere and at all times (over a small enough region for a given precision and amount of curvature). It follows that the speed of light (i.e., of an electromagnetic wave) is the same everywhere and at all times (over a small enough region in a vacuum)
Vendicar_Decarian
1 / 5 (3) Dec 04, 2011
"So we would not be able to tell if these very distant galaxies had light from heavier elements," - Brodix

Why is that?

With the optical spectra now shifted into the Infared you look for the spectral lines of elements other than Hydrogen and Helium in the infared portion of th spectra.

It isn't rocket science.
Benni
1.7 / 5 (6) Dec 04, 2011
"This sounds exactly like a massive concentration of mass just as BB hypotheses states, yet you say such is "conceptually inaccurate". What is it that is conceptually inaccurate? " - Benni

It's not a bag, or a balloon, and it isn't an explosion as you know it, since there is nothing for the matter to explode into. neither is it necessarily finite, a universe that is infinite in extent might exist at the original singularity.

The graphics that depict the BB as an explosion do so out of ignorance and laziness. There was no explosion per say.


You're an Astronomer right? You know this? You're making it sound like a "creation" out of nothingness (God?). All the Astronomers on the Cience & History channels who are videoed outside the Griffith Observatory displaying all those marvelous "big bang animations" haven't a clue as to what they're talking about? And you're getting 5 star post ratings & I'm getting 1's? By the way, I've been to the Griffith Observatory.
Fleetfoot
1 / 5 (1) Dec 04, 2011
The usual graphics are annoyingly misleading. A better depiction would be to imagine a flea that has been sucked into the cylinder of a large deisel engine. When the fuel reaches the right compression, the whole contents burn simultaneously to become plasma. The flea in the centre then sees hot gas cooling and expanding but if he looks farther away he sees a higher temperature because of the finite time the radiation has taken to reach him. That is what we see as the "CMBR", it is light from a mix which was at about 2970 degrees Kelvin now redshifted to the microwave band. The correct picture is that the whole universe was filled almost uniformly with hot gas from the first moment.
Fleetfoot
not rated yet Dec 04, 2011
Another common mis-statement is that, because of the expansion, we cannot actually see out to 13.7 billion light years distance. We see the CMBR "light" that was emitted 13.7 billion years ago but, at that time, the material which emitted it was only about 41 million light years away. Even though it was always travelling at the speed of light through whatever patch of space it was in, it took so long to get here because the gap between it and us was always expanding while it was en route.
brodix
1 / 5 (2) Dec 04, 2011
lomed,
So am I to assume the space between galaxy clusters, as measured by lightspeed, isn't expanding, but there would simply be an increased amount of the lightspeed units, thus taking longer for light to travel between them?
Do you understand that increasing distance is not the same as expanding space?
A train moving away from you is increasing distance, not expanding space. The problem for cosmology is that if it is only increasing distance in stable space, then we would appear to be at the center of the universe. For Big Bang theory to work, it has to be expanding space, yet this overlooks the fact that: "The speed of light (in a vacuum) is a constant and equal to that measured near Earth over any region of space or time that is small compared to its curvature"
How is it that the "vacuum" is stable, if space expands?
brodix
3 / 5 (2) Dec 04, 2011
Vendicar,
Now we are looking in the infrared:
"Spitzer succeeded where Hubble failed because Spitzer is sensitive to infrared light - light so red that it lies beyond the visible part of the spectrum. The newfound galaxies are more than 60 times brighter in the infrared than they are at the reddest colors Hubble can detect."
So it will be interesting to see what comes of it.
Vendicar_Decarian
2.3 / 5 (3) Dec 04, 2011
"You're an Astronomer right?" - Benni

Part of my scientific training is astrophysics.. Yes.

" You're making it sound like a "creation" out of nothingness (God?)." - Benni

Creation requires a beginning and since there was none there is no creation.

"All the Astronomers on the Cience & History channels who are videoed outside the Griffith Observatory displaying all those marvelous "big bang animations" haven't a clue as to what they're talking about?" - Benni

They know. But they lack the ability to provide an animation that imparts the BB idea accurately.

I have provided you with a textual description that is precise in the way it captures the principle.

"And you're getting 5 star post ratings & I'm getting 1's?" - Benni

Because I have provided you with precise information, and you have not digested it.

Vendicar_Decarian
2.3 / 5 (3) Dec 04, 2011
"How is it that the "vacuum" is stable, if space expands?" - Brodix

The vacuum isn't stable. That is why space is expanding.

As to c. It's velocity is measured locally. We do not have the means of measuring c billions of light years away.

We can do it on special occasions at distances that are hundreds of perhaps thousands of light years away.

brodix
2 / 5 (4) Dec 05, 2011
Vendicar,
We have two yardsticks. With lightspeed, if those galaxies clusters are moving apart, we add more such units. That is increased distance. With the other yardstick, redshift, the same units just get stretched out to fill the extra distance. That's expanding space. This is not a problem?
Benni
1 / 5 (2) Dec 05, 2011
"You're an Astronomer right?" - Benni

Part of my scientific training is astrophysics.. Yes.

I have provided you with a textual description that is precise in the way it captures the principle.

Because I have provided you with precise information, and you have not digested it.

Then send us to your blogsite & share with us your expertise that is so far beyond our tiny little Astronomy club to "digest". Two members of our club are engineers, one a teacher, one a musician, one an auto mechanic, one an electronics technician. Our club knows about this site, now we would like to log on to yours.
brodix
1 / 5 (2) Dec 05, 2011
Vendicar,
I would note that obviously we can only measure lightspeed locally, given the Voyager spacecraft have barely reached the heliopause, let alone traveled to other galaxies, but the issue the is theories tying such measurements together and how it can be argued that the very fabric of space expands, in order to explain the observation of redshift of distant galaxies and then turn around and say it will take light longer to bridge these distances and not have to explain what dimension of space it is that maintains this comparatively stable measure.
Fleetfoot
not rated yet Dec 05, 2011
@Brodix:

"The problem for cosmology is that if it is only increasing distance in stable space, then we would appear to be at the center of the universe."

If the distribution is homogenous then there is no centre either way, the problem would be that if galaxies were moving through space and space were not expanding, they could not exceed the speed of light. In the big bang model, space is expanding as you say.

"The speed of light (in a vacuum) is a constant and equal to that measured near Earth over any region of space or time that is small compared to its curvature". How is it that the "vacuum" is stable, if space expands?

The speed of light is actually a geometric limit. If you think of the path of a distant galaxy which happens to be at rest in its local patch of space as a function of time, it appears to move away because the space between us and it is expanding. The speed of light is an angle of 45 degrees relative to the path of that galaxy.

Fleetfoot
not rated yet Dec 05, 2011
@Vendicar:

"As to c. It's velocity is measured locally. We do not have the means of measuring c billions of light years away. We can do it on special occasions at distances that are hundreds of perhaps thousands of light years away."

This paper is controversial as it claims a spatial gradient in the value of the fine structure constant which as you no doubt know is dependent on the speed of light. The claimed variation is about 10 ppm at a range of about 8 billion years lookback time:

http://arxiv.org/abs/1008.3907

It is notable that the gradient they claim is in the opposite sense from their previous paper.

Their value for the purely temporal change is 0.6 /- 1.6 ppm at 1 sigma out to z=1.8 which is entirely compatible with the null hypothesis, an unchanging speed of light.

You may have studied astrophysics but the views you are offering, while well disguised, are far from the conventional model.
brodix
1 / 5 (3) Dec 05, 2011
because the space between us and it is expanding. The speed of light is an angle of 45 degrees relative to the path of that galaxy.

Fleetfoot,
If that galaxy cluster is 2 billion lightyears away, the light could have quite a few turns in its path over time and space to get to us. My point is about the theory. You say "the space between us and it is expanding." The theory assumes it will consequently take light longer, ie, more time, to cross this expanded space. This means that while there is more distance between us and that other galaxy, the speed of light is not relative to that expanding space, but to some other dimension/vacuum. What is this stable vacuum between galaxies which is the basis for lightspeed?
lomed
5 / 5 (3) Dec 05, 2011
So am I to assume the space between galaxy clusters, as measured by lightspeed, isn't expanding, but there would simply be an increased amount of the lightspeed units, thus taking longer for light to travel between them?
Imagine a light beam travelling between two clusters. As measured over any small region along its path its speed will be the same and equal to that near Earth. The two clusters do not move very much within themselves, i.e., the change in distance is not due to the velocity of either cluster (as measured relative to the CMB). It is the space between the galaxies that is expanding.
What is this stable vacuum between galaxies which is the basis for lightspeed?
The vacuum does not need to have the same properties (in particular, geometry) everywhere for the speed of light to be a constant over small regions. Over small regions space follows the rules of special relativity, in which the speed of light is a constant by postulate (axiom).
brodix
1 / 5 (3) Dec 06, 2011
Lomed,
I understand the argument, but I'm still have trouble with the contradiction.
According to theory, the space is expanding, therefore it will take light longer to cross it. If these galaxies are moving away, such that the light takes longer to cross it, you are making a comparison between the space between the galaxies and the measure of space being crossed by light. A lightyear is about 10 trillion miles. So if it is taking more time for light to travel between to point, that means there are more miles between them. Obviously it wouldn't make sense if light did speed up as space increased, because we wouldn't be able to detect it.
brodix
1 / 5 (3) Dec 06, 2011
When we say gravity bends space, it doesn't actually move the source of that light, but bends the path it takes. According to measurements, space is as flat as can be measured, meaning the contraction of gravity and the expansion are in inverse proportion, balancing out their respective effects.
So since it only appears that gravity causes stars to move as their light passes through intermediate gravity fields, could it be that redshift is also a lensing effect? Such that while those other galaxies appear to be moving away from us, this is an optical effect and if we could observe the situation in a billion years, they would still be at the same general distances and still redshifted. That there is an outward curvature, similar to the inward curvature of gravity. This would explain a lot of things, such as why the rate of expansion is directly proportional to distance and resembles a cosmological constant, which was originially proposed to balance gravity.
brodix
1 / 5 (3) Dec 06, 2011
So that way, space can be described as expanding, without having to say it is doing so in terms of stable units of distance. Sort of like walking up the down escalator means you have to walk a greater distance than you travel and the ends are not actually moving away from each other.
lomed
1 / 5 (1) Dec 06, 2011
I understand the argument, but I'm still have trouble with the contradiction.
I do not understand what you think is contradictory.
could it be that redshift is also a lensing effect?
In general relativity (GR), there are three ways to produce a redshift: the doppler effect, kinematically, and gravitationally (covering cosmological and local gravitational effects). The doppler effect is purely classical, i.e., it does not require either of Einstein's theories. It is the only one of the three effects that might reasonably be called illusory. The other two effects are due to the properties of space-time. Since the expansion of space, the doppler effect, and kinematic redshift all require motion (measured, e.g., with respect to the CMB) the only way to produce redshift without motion is for it to be due to light escaping from a gravitational "well". However, if a system's gravitational well produces a redshift of more than 0.5 it is unstable to collapse into a black hole.
brodix
1 / 5 (2) Dec 06, 2011
lomed,
Because a stable speed of light would require a stable dimension of space. If there are simply more lightyears separating the two points, what is the frame on which this measure is based?
As with the doppler effect, the train is moving away in stable space, ie. it is putting space that was front of it, behind it, not that the space is being stretched. So if those galaxies are moving away and there are more lightyears between them, they are putting space, as measured in lightyears, that was outside the distance between them, in between them. This isn't stretching space, but increasing the amount of stable space.
Shinichi D_
1 / 5 (2) Dec 06, 2011
Because a stable speed of light would require a stable dimension of space.

Just an idea, I'm a total outsider:
"Stable space is only relevant, where the light is now" Sorry. It's called Planck lenght.(?) Immagine light traveling Planck lenght by Planck lenght for 13 billion years. The distance of these redshifted galaxies was streched from about 3 billion lightyears to about 25-30 billion in this timeframe. All along the light traveled at the same speed, and covered 13 billion lightyears-worth of planck lenghts.

lomed, correct me please if i'm disastrously wrong here. I'm curious too.
brodix
1 / 5 (2) Dec 06, 2011
Shinichi,
Whether your unit of distance is planck lengths, or lightyears, the same point holds. If the number of these lengths is increasing, that's an increased amount of stable space, as measured by that unit. If we use a stable unit to measure an expanding frame, what is the basis of that unit?
Fleetfoot
not rated yet Dec 07, 2011
@Brodix:
Fleetfoot
5 / 5 (1) Dec 07, 2011
Brodix: "If that galaxy cluster is 2 billion lightyears away, the light could have quite a few turns in its path over time and space to get to us."

That shows up as gravitational lensing which is a small effect at best.

"You say 'the space between us and it is expanding.' The theory assumes it will consequently take light longer, ie, more time, to cross this expanded space. This means that while there is more distance between us and that other galaxy, the speed of light is not relative to that expanding space, but to some other dimension/vacuum."

Light travels at c relative to any free-floating matter in the region of space through which it is passing, that is the basic rule of relativity. The light crosses the first one 300,000km of distance to us in one second, i.e. at the usual speed. During that time the space ahead of it (and behind it) expands by some amount so the distance remaining reduces by less than one light-second. It covers the next lightsecond at the same speed etc..
brodix
1 / 5 (2) Dec 07, 2011
Fleetfoot,
If I'm driving down a road at fifty mph and someone else passes me at ninety mph, the distance between us will increase, but that doesn't change the length of a mile.
So the space is expanding while the light is in transit. You are still using a stable unit to measure the distance. Even if the distance is increasing during this process, the size of the units are not affected by the change in distance, just more are required. If space is expanding, what determines the stability of this unit of measure?
Shinichi D_
1 / 5 (1) Dec 07, 2011
brodix:
"If space is expanding, what determines the stability of this unit of measure?"

Physical constants.

"Whether your unit of distance is planck lengths, or lightyears, the same point holds."

i didn't suggested to change the unit of measure. I tried to point out, that space expands in a different way in large and in small scale. In large scale, it seems to strech. But at the very small scale the stucture of vacuum becomes "grainy". You reach a point, where it's made up by "units" that can not be streched or devided. To strech it at large scale, you have to add more and more of these units.

lomed
5 / 5 (1) Dec 07, 2011
Because a stable speed of light would require a stable dimension of space. If there are simply more lightyears separating the two points, what is the frame on which this measure is based?
In fact a stable speed of light (over small regions) is more fundamental than either a constant measure of space or a constant measure of time. This concept is key to both the special and general theories of relativity.
Even if the distance is increasing during this process, the size of the units are not affected by the change in distance, just more are required. If space is expanding, what determines the stability of this unit of measure?
Most everyday measuring devices would (if put in deep space where the expansion is occurring) exhibit no expansion since they are bound together (by electromagnetic forces). Only systems of objects so tenuous as to not be bound systems (i.e., have more potential than kinetic energy relative to infinity) would expand.
lomed
5 / 5 (1) Dec 07, 2011
All along the light traveled at the same speed, and covered 13 billion lightyears-worth of planck lenghts.

lomed, correct me please if i'm disastrously wrong here. I'm curious too.
You reach a point, where it's made up by "units" that can not be streched or devided. To strech it at large scale, you have to add more and more of these units.
I am not aware of any way (off-hand) to support or refute your ideas. You seem to be referencing something related to quantum gravity. However, it is not length that is quantized in quantum gravity, rather it is areas and volumes that come in integer multiples of a small value in the general vicinity of the planck length squared and cubed, respectively. The planck length is special in that quantum phenomena involving gravity are thought become important over such sales, but I doubt the universe is considered entirely discrete in any mainstream version of the theory.

Without data we can't determine the correctness of your idea.
brodix
1 / 5 (3) Dec 07, 2011
lomed,
Most everyday measuring devices would (if put in deep space where the expansion is occurring) exhibit no expansion since they are bound together (by electromagnetic forces). Only systems of objects so tenuous as to not be bound systems (i.e., have more potential than kinetic energy relative to infinity) would expand.

In fact, gravitationally bound systems contract. Some so forcefully that light cannot escape and contracts as well. So it is only between these bound systems that space expands. According to measurements by COBE and WMAP, the expansion of space and its gravitational contraction are inversely proportional, resulting in flat space. So if space is falling into these bound systems at the same rate as it is expanding between them, where is the overall expansion coming from?
This might explain why the expansion resembles a cosmological constant, which was originally proposed to balance gravity.

lomed
5 / 5 (2) Dec 08, 2011
According to measurements by COBE and WMAP, the expansion of space and its gravitational contraction are inversely proportional, resulting in flat space. So if space is falling into these bound systems at the same rate as it is expanding between them, where is the overall expansion coming from?
The WMAP results do indicate that the universe is nearly flat on large scales. This flatness has nothing to do with the fact that space is expanding. The friedmann equations indicate that space can expand in a universe of positive, zero, or negative curvature. It is true that there are regions of space that are positively curved (where there are galaxies), but there are also vast regions of space that have practically no matter and seem to exert a negative pressure (due to the cosmological constant, note that the energy density is still positive in these regions but its gravity is overwhelmed by its pressure, so these regions are very flat), with the average being approximately flat.
lomed
5 / 5 (2) Dec 08, 2011
Perhaps "nothing to do with" was a little too strong. A more accurate phrase would be something like: "is logically independent of". The curvature of the universe indicates its fate. In general, the expansion of space will be greater in a negatively curved universe and less in a positively curved one as compared to a flat universe for the same initial and boundary conditions on the scale and density, respectively. However, with the appropriate initial and/or boundary conditions and equation of state one could have contraction in a negatively curved space, expansion in positively curved one, etc.
Vendicar_Decarian
1 / 5 (1) Dec 08, 2011
"We have two yardsticks. With lightspeed, if those galaxies clusters are moving apart, we add more such units. That is increased distance." - Brodix

Yes, but you aren't there to experience the speed of separation.

Two objects can separate at speeds > c to a third observer. It is only motion relative to the observer that is constrained to be < c.

c is measured locally, and is a measured constant.

Vendicar_Decarian
1 / 5 (2) Dec 08, 2011
Then send us to your blogsite & share with us your expertise that is so far beyond our tiny little Astronomy club to "digest"" - Benni

Sorry Benni, I neither have a web site, or a blog. So feel free to cut and paste what has been said here.
Vendicar_Decarian
1 / 5 (2) Dec 08, 2011
"in order to explain the observation of redshift of distant galaxies and then turn around and say it will take light longer to bridge these distances and not have to explain what dimension of space it is that maintains this comparatively stable measure." brodix

Sorry, I don't understand your complaint.

c is a local diffusion constant.

Electro-magnetism is such that the average rate of propagation - limited by the diffusion effect of the quantum vacuum - is c, and it is c everywhere since the diffusion constant is apparently c everywhere.

c, dl and dt are linked such that if c changes then we infer either a change in the local dl or dt.

On large scales we observe that the universe appears to be expanding. Yet in the limit as dt goes to zero, dl/dt goes to c.

As a practical matter we don't have an accurate enough standard for length to detect the expansion of the universe in the lab by measuring dl and dt.

Vendicar_Decarian
1 / 5 (2) Dec 08, 2011
"You may have studied astrophysics but the views you are offering, while well disguised, are far from the conventional model." - fleetfoot

Well, certainly they differ in terms of the animations provided to students, but the results are the same.
Vendicar_Decarian
2.3 / 5 (4) Dec 08, 2011
"You say "the space between us and it is expanding." The theory assumes it will consequently take light longer, ie, more time, to cross this expanded space. " - Brodix

Time is a pretty tricky thing as it means different things to different people.

For example, to the photon the time needed to travel from the big bang to your eye is Zero seconds.

What we do when we look at distant galaxies, is impose a linear relationship and assume that dt and dl for us is the same dt and dl for distant galaxies. For low recessional velocities, this practical assumption is a good one, but as apparent recessional velocities approach c, then that linear assumption begins to produce confusing results.

One such result is that the universe had an origin. But again to a photon that origin was 0 seconds ago.

In reality as you get closer to the "origin" of the universe there are various competing factors that confuse what time is, one of which is the energy density which tends to infinity Cont.
Vendicar_Decarian
1.8 / 5 (5) Dec 08, 2011
and thereby slows the passage of time by increasing the vacuum diffusion constant that limits c.

Higher spatial energy densities reduce the value of c. As energy density increases to infinity, c decreases to zero relative to a distant flat space coordinates that are projected toward the past. Yet locally it is thought that c remains constant so either local dl and local dt must decrease to produce the same value of c.

So we see lengths contracting and local time contracting as the universe approaches the singularity. The sum of the local time goes to infinity for the local observer, but since we project our time linearly into the past, we see an initial time.

So proper time since the origin is infinite, we see the time to the beginning as having a fixed origin and a photon sees the beginning as now.

It is all a matter of perspective.
Vendicar_Decarian
1 / 5 (3) Dec 08, 2011
"So the space is expanding while the light is in transit. You are still using a stable unit to measure the distance." - Brodix

Again. c is a local diffusion constant.

We do not have instrumentation accurate enough to measure the expansion of the universe by detecting variance in c. If we did then we would conclude that the variance in c was a result of the expansion of the universe.

c is "constant" only in small regions.

As a practical matter, if a variance of c was observed it would be attributed to something other than a variance in c in order to keep c constant.

If such an observation were made, there would be considerable debate of the merits of how to proceed and keep science consistant. But because physicists love their constants undoubtedly they would keep c, and manufacture new physical laws to explain how c is really not changing.

Such re-definitions of physical laws show how science is mutable and ultimately about prediction rather than explanation.

Benni
2.1 / 5 (7) Dec 08, 2011
"You may have studied astrophysics but the views you are offering, while well disguised, are far from the conventional model." - fleetfoot

Well, certainly they differ in terms of the animations provided to students, but the results are the same.


Every physicist I have ever known has written a paper on something, it's how they get name recognition within their profession, by their association in professional organizations. Send us to one of the organizations of which you are a member so we can evaluate abstracts & papers you have submitted.
brodix
1 / 5 (3) Dec 08, 2011
When we say gravity contracts space, we understand it is a relativistic effect of measurement, but when we say space expands, suddenly it's a classical measurement and those other galaxies have to be moving away in standard linear fashion. Galaxies are not simply large particles in space. They are dynamic systems which are pulling material for tens to hundreds of millions of lightyears around them, bending light passing anywhere close and radiating out light and other forms of energy for billions of lightyears. So if gravity curves space in, how do we know the opposing radiation of light isn't curving it out ever so gradually over those billions of lightyears? Such that it causes space to expand between galaxies, as it is collapsing into them.
brodix
1 / 5 (3) Dec 08, 2011
Everyone here keeps knowingly pointing out that we can't measure lightspeed over intergalactic distances, or even outside controlled conditions on earth, but I would like to point out that we haven't measured any effect of and on light over intergalactic distances. Insisting this expansion must be a classic effect resulting in increasing static distances seems to entirely overlook the nature of relativity and how it describes the potential of spacetime.
So we have these enormous theoretical patches, from inflation to dark energy, to make this ad-hoc explanation work, while observations supporting redshift being evidence of a cosmological constant, as originally proposed, to balance gravity, is overlooked, since groupthink insists on the Big Bang. As the article states, "We've had to go to extremes to get the models to match our observations,"
lomed
5 / 5 (1) Dec 08, 2011
When we say gravity contracts space, we understand it is a relativistic effect of measurement, but when we say space expands, suddenly it's a classical measurement and those other galaxies have to be moving away in standard linear fashion.
Both the contraction and the expansion of space are equally real effects no matter on what scales they occur (they are not defects in our ability to measure). That there should be expansion or contraction is a prediction of GR. Given some simplifying assumptions (that are borne out by observations), one obtains the friedmann model (which predicts the observed cosmological redshift is due to expansion) directly from GR. If there were a better supported theory to explain the observed redshift in a way usefully more accurate than GR scientists would use it, there isn't one as of yet. All of the other once plausible theories: light scattering, variable speed of light, changing laws of physics, etc. have been shown to disagree with observations.
lomed
3 / 5 (2) Dec 08, 2011
So if gravity curves space in, how do we know the opposing radiation of light isn't curving it out ever so gradually over those billions of lightyears?
The pressure of light does reduce the (spatial) curvature somewhat (compared to an equal density of matter), but its energy density more than makes up for the pressure leading to a net positive curvature of both time and space due to light alone.
Insisting this expansion must be a classic effect resulting in increasing static distances seems to entirely overlook the nature of relativity and how it describes the potential of spacetime.
There are certainly other ways to describe the motion in GR, but the net result (i.e., what can be physically measured) is the same. Explaining the redshift in other ways (in GR) requires one to take a different perspective, the one I have been talking about so far assumes the CMB to have all been emitted at approximately the same instant and time is taken to pass at a uniform rate (on average)
brodix
1 / 5 (2) Dec 08, 2011
lomed
5 / 5 (2) Dec 08, 2011
http://www.fqxi.o...kets.pdf
It's an interesting paper that indicates a mechanism that would produce a redshift in a wavepacket of light.

However, said mechanism would not be a good explanation for the cosmological redshift. Since it produces redshift via dispersion and attenuation it would change the shape of the spectra observed with respect to that emitted. For example, one would expect a hot gas to emit thermally like a blackbody, but with this sort of redshift one would not receive a blackbody spectrum. Rather, the observed spectrum would be broader and have the lower frequencies enchanced (in addition to having its peak shifted to a lower frequency). In particular, this would happen to the CMB contrary to observation. It would also lead to discrepancies between the observed absorption line of gases and the temperatures indicated by the overall shape of the (thermal) spectra.
brodix
1 / 5 (3) Dec 09, 2011
lomed,
The point isn't that it's an answer to everything, but that there are far too many angles to this issue for Big Bang theory to be more than speculative, rather than taken for granted by anyone who wishes to taken seriously. Additions such as inflation and dark energy really are nothing more than enormous gaps between theory and observation.
With all the various advanced telescopes coming on line, I suspect the problems will become more obvious.
lomed
5 / 5 (3) Dec 09, 2011
there are far too many angles to this issue for Big Bang theory to be more than speculative, rather than taken for granted by anyone who wishes to taken seriously.
The big bang theory is a direct result of the application of our best theory of gravity to (model a simplified version of) the data we have about the universe. To say it is incomplete is a reflection of the incompleteness of our knowledge (data) and understanding (theory) of the universe. I do not say that the big bang is the last word on the past history or beginning of the universe (if such a thing occurred), only that it is our best understanding given our current knowledge. As such, it makes sense that anyone who wishes to be taken seriously in cosmology should understand GR before attempting to improve upon it (How else would one know what needs improving?).
With all the various advanced telescopes coming on line, I suspect the problems will become more obvious.
And hopefully more amenable to solution.
brodix
1 / 5 (2) Dec 10, 2011
To be continued in the event of further observations.....
LarsKristensen
1 / 5 (3) Dec 23, 2011
The big question I suppose:

What can we can not observe 13 billion light years away.

Could we see the Milky Way 13 billion light years away, would the majority of the light we can see from the stars in the Milky Way to be gone. Most of the stars will disappear at a distance of 13 billion light years and the stars who has the strongest evidence of metals will be gone.

The scientific term for things science can not observe is that it does not exist.

Perhaps the reason that the most distant galaxies do not have stars with high metal display, may be because astronomers can not observe them, because their light is too weak.
rawa1
1 / 5 (2) Dec 23, 2011
The big bang theory is a direct result of the application of our best theory of gravity to the data we have about the universe.
The epicycle model was direct application of the geometry to the astronomical data as well. Only subtle qualitative deviations (order of Venus phases) indicated, something may be wrong with this model. But the formal math of epicycle theory provided the same results, like the Kepler's law (because it has been fitted to the experimental observations with many parameters) - so there was no formal reason to replace it with Copernician model. It's math was as reliable, as the Copernician model regarding various predictions of eclipses and conjunctions. Nevertheless, just these subtle inconsistencies has caused, the epicycle model was replaced later with more advanced theory. Actually, the formal math is only rarely the actual reason of switch of theories, because every formal theory can be "adjusted". The problems are inconsistencies at the logical level.
Seeker2
1 / 5 (2) Dec 24, 2011
I don't think we have to worry about the dl/dt problem if we take relativity seriously, as Einstein believed we should treat time and space on an equal footing. Problem being Einstein didn't realize important implications of his theory. That is if you consider the passage of time as expansion in the time dimension space should also be expanding at the same rate.
Seeker2
1 / 5 (1) Dec 24, 2011
Actually as Dirac and Feynman realized time passes in both the forward and backwards direction - forward for matter and backwards for antimatter - consistent with the Einstein equations. As Feynman explained positrons go backwards in a synchrotron relative to the electron but actually we're watching the positrons run in reverse time. If they do that in an electromagnetic field then I see no reason why they shouldn't also do that in a gravitational field. I wonder if Feynman ever thought about that. The current time which we view is actually the current time in both forward and backward directions.
Vendicar_Decarian
1.8 / 5 (4) Dec 25, 2011
"Both the contraction and the expansion of space are equally real effects no matter on what scales they occur" - Lomed

Really? You mean that the universe really does get 2.5 billion miles less wide as you accelerate in your car from 0 to 60 mph?

How does space know how to do this? And doesn't that rate of contraction exceed c?

How do you manage to send a message to the far side of the universe in the 6 seconds it takes you to accelerate to 60 Mph?

The contraction and expansion of space are real are they?
Vendicar_Decarian
1 / 5 (4) Dec 25, 2011
"Actually as Dirac and Feynman realized time passes in both the forward and backwards direction - forward for matter and backwards for antimatter" - Seeker2

The proposition is that two positrons are two electrons moving backward in time.

Place two positrons side by side and since both have positive charge they repel.

Reverse the arrow of time and you have two electrons sitting side by side and they attract.

Since that is not what is seen in the real world it follows that time reversal does not convert electrons into positrons or positrons into electrons.

Vendicar_Decarian
2 / 5 (4) Dec 25, 2011
"Most of the stars will disappear at a distance of 13 billion light years and the stars who has the strongest evidence of metals will be gone." - LarsK

Claptrap.

The proportion of light from metal abundant and metal free stars would be the same.

All dim at the same rate.
Callippo
1 / 5 (1) Dec 25, 2011
Reverse the arrow of time and you have two electrons sitting side by side and they attract.
They will attract from their own time arrow perspective, but still repel from out time arrow perspective. The same applies for two antimatter particles. Their sign of gravity will be reversed, but their time arrow too, so you will observer nothing particular. The things will change a bit when antiparticle will interact with particle at various distances.
Benni
2 / 5 (4) Dec 25, 2011
Their sign of gravity will be reversed,

Are you suggesting gravity has polarity?
Seeker2
1 / 5 (1) Dec 25, 2011
time reversal does not convert electrons into positrons or positrons into electrons.
Actually there would be two arrows of time pointing in opposite directions as long as the U is expanding (in space and time). Time reversal occurs only when the U starts to recollapse and the arrows of time point inward. You could call this the reheating phase. No matter or antimatter can form in this phase because no condensation is possible. Matter and antimatter coexist as time runs (expands) in opposite directions just as each spatial dimension.
Seeker2
1 / 5 (1) Dec 25, 2011
Actually the U is going nowhere in space or time. Only expanding and contracting like a living heart. So you could say the U is a living breathing being.
Seeker2
1 / 5 (1) Dec 25, 2011
Feynman illustrates the concept of a positron as an electron moving in the reverse direction in a synchrotron so as to appear as having opposite charge as that of the electron. He didn't push the idea of antimatter moving in the reverse direction in a gravitational field. I wonder if he ever thought about that.
Callippo
1 / 5 (1) Dec 25, 2011
Are you suggesting gravity has polarity?
In dense aether model the pressure of radiation is the force opposite to gravity.
Benni
1 / 5 (1) Dec 26, 2011
Are you suggesting gravity has polarity?
In dense aether model the pressure of radiation is the force opposite to gravity.


Does AWT presume "radiation" (electro-magnetic waves), counter oppose gravity with exactly the same "force"?
Callippo
1 / 5 (2) Dec 26, 2011
Does AWT presume "radiation" (electro-magnetic waves), counter oppose gravity with exactly the same "force"?
Yes, but not only electromagnetic waves. In AWT the gravity is generally considered a shielding of all possible forms of radiation, including the invisible flux of gravitons.

http://aetherwave...age1.gif

In massive stars and galaxies the pressure of EM radiation is really the main force, which defies their gravity. But this radiation is of long distance character and volatile and such stars evaporate in this way. When the density of star increases above certain limit, it crashes and the another, short dist. radiation must apply in form of radiation pressure of gluons and W/Z bosons. And the large galaxies are held apart with dark matter, which is the manifestation of graviton flux, i.e. the flux of gravitational waves. The shielding of all these waves contributes to the attractive forces too for the sake of symmetry of the whole model
LarsKristensen
1 / 5 (2) Dec 26, 2011
How far away will the matter we are made of, have moved? Calculated by the now accepted expansion of the universe?

The matter we are made of, can hardly have moved 13.5 billion light years over 13.5 billion years, just as light has done it?

There is something rotten in the state of the Universe. (Adapted from William Shakespeare's "Hamlet")

Big Bang is the evil uncle who try to defraud Hamlet, by using machinations and not acknowledged lies.
antialias_physorg
1 / 5 (1) Dec 26, 2011
How far away will the matter we are made of, have moved? Calculated by the now accepted expansion of the universe?

The matter we are made of, can hardly have moved 13.5 billion light years over 13.5 billion years, just as light has done it?

I think you need to revisit the idea of what 'expansion' actually means. That should clear up your confusion.
Seeker2
1 / 5 (1) Dec 26, 2011
And the large galaxies are held apart with dark matter,...
So dark matter is actually a form of anti-gravity.
Seeker2
1 / 5 (1) Dec 26, 2011
The matter we are made of, can hardly have moved 13.5 billion light years over 13.5 billion years, just as light has done it?

Matter hitches a ride on spacetime.

There is something rotten in the state of the Universe.
The current state of the U is unknown and unknowable. The only thing we can observe is what happened in the past. As for the present we just have to use our imagination.
Seeker2
1 / 5 (1) Dec 26, 2011
comment deleted
Seeker2
1 / 5 (1) Dec 26, 2011
I think you need to revisit the idea of what 'expansion' actually means. That should clear up your confusion.

Well maybe maybe not. I've been seeing something about spacetime expanding only between elements of matter. So molecules, for example, would hold together no matter how much spacetime expanded. I'd think not. In which case molecules would dissociate as matter expanded. Maybe even atoms would fall apart. Interesting.
Benni
1 / 5 (1) Dec 27, 2011
Does AWT presume "radiation" (electro-magnetic waves), counter oppose gravity with exactly the same "force"?
Yes, but not only electromagnetic waves. In AWT the gravity is generally considered a shielding of all possible forms of radiation, including the invisible flux of gravitons.

In massive stars and galaxies the pressure of EM radiation is really the main force, which defies their gravity. But this radiation is of long distance character and volatile and such stars evaporate in this way. When the density of star increases above certain limit, it crashes and the another, short dist. radiation must apply in form of radiation pressure of gluons and W/Z bosons. And the large galaxies are held apart with dark matter, which is the manifestation of graviton flux, i.e. the flux of gravitational waves.


I'm curious, does AWT consider "gravity flux" as having an electro-magnetic component?
antialias_physorg
1 / 5 (1) Dec 27, 2011
I've been seeing something about spacetime expanding only between elements of matter. So molecules, for example, would hold together no matter how much spacetime expanded.

Atomic/electromagnetic forces do not get weaker because of the expansion of space - so the distance of atoms to one another will stay the same (i.e. any expansion within an atom/molecule will immediately be 'rectified' by the (sub)atomic particles moving back to the equilibrium positions of all the forces acting on them).
Callippo
1 / 5 (2) Dec 27, 2011
I'm curious, does AWT consider "gravity flux" as having an electro-magnetic component?
The gravity is static field, it would require some rotating or moving body. From sufficiently hyperdimensional perspective the space-time drag effects would appear similarly.

http://www.aether...hism.gif

In linearized, EinsteinMaxwell theory on flat spacetime, an oscillating electric dipole is the source of a spin-2 field, i.e. gravitational waves or graviton flux

http://rspa.royal...987.full

So I presume, in hyperdimensional Einstein's field theory the rotating massive body would generate the spin-1 field, i.e. the flux of photons. Maybe the Hawking radiation of black holes is such a field actually, if we imagine, beneath the event horizon there are many wildly moving singularities (which would appear like galaxies in our generation of Universe).
Callippo
1 / 5 (2) Dec 27, 2011
Atomic/electromagnetic forces do not get weaker because of the expansion of space - so the distance of atoms to one another will stay the same
I do understand it, but it still effectively invalidates the Big Bang theory, in which space-time would expand at all levels. What's worse, we are observing the remote galaxies collapsing instead of expanding.

http://arxiv.org/abs/1011.4956

The AWT explains it with dispersive nature of Hubble red shift - only waves/objects smaller than CMBR field appear expanding, the waves/objects larger than CMBR field appear collapsing instead. After all, the ripples at the water surface are doing the very same.

http://www.aether...ples.jpg

The trick is in the point, we are observing the expansion of Universe from inside above CMBR wavelength scale, so it appears like contraction instead. The entropic time arrow does the very same and it switches its sign around CMBR wavelength scale.
antialias_physorg
1 / 5 (1) Dec 27, 2011
in which space-time would expand at all levels.

What does that even mean? Are you making things up again?

What's worse, we are observing the remote galaxies collapsing instead of expanding.

So? There is a thing called gravity. Ever heard of it?

Remember: Stuff coalesced into matter some time after the big bang.
That elecrtromagentism is very strong dos not mean it is stronger than anything at all. Given enough energy it can be overcome (and at the big bang enough energy was to be had in abundance)
Callippo
1 / 5 (2) Dec 27, 2011
The simplest way, how to imagine such a strange geometry is an assumption, we are huge foamy object embedded into another foam. The whole complexity of observable reality emerges as a moire effect of both foams, which are overlapping mutually like two pieces of fabric. After the Universe at the space-time scale smaller, than the wavelength of this moire (CMBR or human observer scale, ~ 2 cm) would appear expanding and the remaining side of it would appear collapsing.

The similar effect we can observe inside of dark Alexander band between primary and secondary rainbows during heavy rain, where the dense rain droplets become similar to foam with both positive, both negative curvature in similar way, like the density fluctuations of vacuum (CMBR noise). The dark band corresponds the empty cosmic space after then, the rainbows correspond the objects smaller and larger than rain droplets.
Callippo
1 / 5 (2) Dec 27, 2011
What does that even mean? Are you making things up again?
This means, the Big Bang theory considered the expansion of Universe as a whole before inflation, after inflation only the space-time between massive particles is considered expanding for the sake of consistency with observable reality. It's inconsistency of this model - it's fitted to observable reality in this point, instead of predicting it. Whole the Big Bang theory is constructed from such ad-hoced assumptions like the epicycle model of solar system of Galileo era. It doesn't mean, such model cannot work at the quantitative level - on the contrary - but it's broken at the logical level and it generates postdictions and interpolations, rather than extrapolations, because it's merely the regression of observable reality, rather than the theory. In AWT the formal logics is dual to quantitative rigor and the formal theories must be broken at logical level at least a bit for to be able to predict at least something.
antialias_physorg
3 / 5 (2) Dec 27, 2011
The simplest way, how to imagine such a strange geometry is an assumption, we are huge foamy object embedded into another foam.


This means, the Big Bang theory considered the expansion of Universe as a whole before inflation,

Ah. So you're just making stuff up. Thought so.
Callippo
1 / 5 (2) Dec 27, 2011
So you're just making stuff up. Thought so.
Nope. The Big Bang theory considers omnidirectional expansion of space-time at all levels. The space-time between particles of atoms doesn't differ conceptually from cosmic space, so it should expand in similar way. The Big Bang theory cannot account into it by itself, as it doesn't provide the theory for electromagnetic and nuclear forces, which prohibit such an expansion. If it suddenly says, the space-time cannot expand omnidirectionally bellow CMBR wavelength scale, it just adjusts its general concept to local observational reality, i.e. it introduces new ad-hoced postulate into its formal logic. It just requires a bit of consequential thinking to realize it.

It's just Big Bang theory, which is forced to making stuffs up - not me.
Callippo
1 / 5 (2) Dec 27, 2011
Try to imagine, we could observe the Universe in radiowaves only. In these long wavelength waves only very large surface details of objects would be observable. The appearance of Universe would change significantly after then. The more distant objects would appear larger, more luminous and blue shifted, than the more close ones. The independent observer would say, whole the Universe is falling to us.

You may believe it or not - but this is exactly the prediction of dense aether model, which still waits for its confirmation. For example, in the last year the US astronomers announced surprising results from a high-altitude balloon experiment called ARCADE-2, which had made careful measurements of the sky at radio wavelengths. The background radio emission, which is the component smoothly distributed across the whole sky, was six times brighter than anyone was expecting.
Callippo
1 / 5 (2) Dec 27, 2011
With respect to quantum mechanics theory it appears quite natural, the elementary particles radiating energy of gamma rays of higher frequency, the the atom nuclei as a whole and the atom nuclei are emanating X-rays rather than visible photons, like the atoms do as a whole. In AWT it's simply manifestation of strong blue shift, which is dual to the Hubble red shift above the CMBR wavelength scale. The Universe appears collapsing wildly bellow this wavelength scale - but surprisingly nobody considers it as an evidence of future space crush at the Planck scale - why not? IMO such conclusion would use the very same logics, like the mainstream cosmologists are using in their interpretation of Hubble red shift. But this logics appears nonsensical at the first look bellow CMBR scale - so why to use it above this scale?
Callippo
1 / 5 (2) Dec 27, 2011
The Big Bang cosmology is questioned more and more often and new alternative models of it are proposed
http://arxivblog.com/?p=335 http://arxiv.org/abs/1007.1750 http://arxiv.org/abs/1009.0953

Is the universe really expanding? http://www.aether...ette.pdf

Did the Universe Have a Beginning?
http://www.metare...ning.asp

Callippo
1 / 5 (2) Dec 27, 2011
Public voting suffers with its apparent limit at the case of discussions about boundary phenomena or interpretations http://www.aether...rac1.gif
Whereas the mild proponents of new ideas face mild negativism of many people, the strong proponents of new ideas are coupled with strongest opponent in 1:1 ratio similar to pairing of particles and antiparticles inside of boson condensate.
Seeker2
not rated yet Dec 27, 2011
In AWT it's simply manifestation of strong blue shift, which is dual to the Hubble red shift above the CMBR wavelength scale.
What is the CMBR wavelength scale?
Benni
1.8 / 5 (5) Dec 27, 2011
I'm curious, does AWT consider "gravity flux" as having an electro-magnetic component?
The gravity is static field, it would require some rotating or moving body. From sufficiently hyperdimensional perspective the space-time drag effects would appear similarly.


Again same question: Does AWT assign an electro-magnetic component to gravity? YES or NO. Forget all this other stuff for the moment, we can get into that later.
LarsKristensen
1 / 5 (2) Dec 27, 2011
I think you need to revisit the idea of what 'expansion' actually means. That should clear up your confusion.


The objects will not move in space, it is the space that is expanding. That's the truth.

But is it the truth about the universe or is it just a theory? A theory there only tells us that we humans know nothing about, but so very like to want to believe.

One is what science people think and say, but something quite different is how the universe manifests itself.

The universe does exactly what it wants and does not ask us humans permission to do what it is doing.

Do not science people to gods who think they know the truth about the universe. For do you so, you will do science to a religion and science is not a religion.

Remember, science people say they only know of less than 5% of all the universe is composed.

If you know less than 5% of something, you know almost nothing about it.

And that is truth. Believe it or not.
Callippo
1 / 5 (1) Dec 28, 2011
Does AWT assign an electro-magnetic component to gravity? YES or NO.
In AWT the gravity is statical shielding force, electromagnetism is dynamic effect of moving charges. Without motion of massive body you cannot have any electromagnetism.
What is the CMBR wavelength scale?
It's distance scale around 2 cm, in AWT it corresponds the middle of the distance scale of the observable Universe. Above this size we are observing the Universe from inside of it, bellow it from outside. It's the dimensional scale of highest complexity of the observable Universe.
Callippo
1 / 5 (1) Dec 28, 2011
The objects will not move in space, it is the space that is expanding. That's the truth.
Nope - the truth is, the remote objects appear reddish with distance. Everything else is speculation. There are two main possible explanation: the Doppler shift of the light wavelength due the omnidirectional expansion of space (which we don't know, if exists as it's the only evidence of it) and the Stokes dispersion of light with density fluctuations (which are known to exist, as it has many other manifestations in experiment and observations).
Benni
1.7 / 5 (6) Dec 28, 2011
Does AWT assign an electro-magnetic component to gravity? YES or NO.
In AWT the gravity is statical shielding force, electromagnetism is dynamic effect of moving charges. Without motion of massive body you cannot have any electromagnetism.


For some reason I can't get YES or NO from you no matter how many times I ask the same question. So maybe if I ask the question a slightly different way: "Do the same laws that govern electro-magnetism also apply to gravity in AWT"?
Callippo
1 / 5 (2) Dec 28, 2011
Do the same laws that govern electro-magnetism also apply to gravity in AWT"
AWT doesn't use any formal laws, but it should be able to demonstrate, the fluid behavior of dense particle gas around massive objects is driven with the similar equations, like the elastic fluid between charged bodies, described with Maxwell's equations.
http://www.aether...hism.gif
So that the answer is: "YES, but in limited extent". For example, gravitational waves, if exists apply to higher number of dimensions, than the electromagnetic waves. So that the gravity laws can describe gravitomagnetism with vortex field in 4D, but I'm not sure about gravity waves. There is definitely certain similarity, but every theory which will use this similarity too literally will be wrong. You'll need substantially higher number of dimensions to reconcile the gravity theory and EM theory, then the number of dimensions in which these theories operate by now.
Callippo
1 / 5 (2) Dec 28, 2011
Actually the same problem exists for general relativity and quantum mechanics. There are some common points, which these theories share, but in general these theories differ so much, you'll need to introduce high number of extradimensions to reconcile them. From our low-dimensional perspective every such generalized theory will appear pretty fuzzy and noisy, so we will actually fit two noisy objects each other. Everyone can feel, this principle is essentially feasible, but its reliability and testability will not be very high, because the same additional information, which we will use for reconciliation of these theories will be lost for low dimensional observers. I'm not convinced about practical usefulness of such mathematical games at all - no matter whether they're feasible or not, because the modified theories will be very complex, heavily parametrized and poorly conditioned (i.e. difficult to enumerate and full of unphysical singularities and/or falsely smooth solutions instead).
Benni
2.3 / 5 (6) Dec 28, 2011
Do the same laws that govern electro-magnetism also apply to gravity in AWT"
AWT doesn't use any formal laws, but it should be able to demonstrate, the fluid behavior of dense particle gas around massive objects is driven with the similar equations,


All those math courses I took to get my Engineering degree, and now I find out once I get beyond Earth's orbit they no longer mean anything. Okay GR & QM, move over, the mathlessness of a new "wave" proposes to engulf astro-physics to placate the mathematically challenged.
Callippo
1 / 5 (2) Dec 28, 2011
once I get beyond Earth's orbit they no longer mean anything. Okay GR & QM, move over..

It's not so bad. We are random fluctuation of it and we can observe it in transverse waves at two zones corresponding the energy density / distance scale of atom nuclei and the stars composed of atom nuclei.

http://www.aether...cale.gif

It means, the application scope of general relativity and quantum mechanics is limited to two zones of dimensional scale and the rest of Universe must be described with less or more ad-hoced extrapolations of these two theories. Outside of these limits the Universe is indeterministic and random and the low dimensional deterministic models become poorly conditioned there.

This problem may be solved conceptually easily with introduction of additional dimensions into existing theories, and the string theory is the another step in this direction (actually Heim's theory was really first hyperdimensional theory).
Seeker2
1 / 5 (1) Jan 01, 2012
AWT doesn't use any formal laws,


Previous posts indicate its primary purpose is to irritate the mainstream physics community.

You'll need substantially higher number of dimensions to reconcile the gravity theory and EM theory,
My view is that all matter and (force) fields are the result of some particular configuration (curvature) of spacetime, either at the macro or quantum scale. At the quantum scale only certain configurations are allowed. I don't buy the idea about two zones of dimensional scale at about 2cm as if the CMBR has some particular wavelength. I'm also having problems with the idea of a dimensional scale. I should hope dimensions would be scalar invariant.
Seeker2
1 / 5 (1) Jan 02, 2012
Outside of these limits the Universe is indeterministic and random and the low dimensional deterministic models become poorly conditioned there.
I think this means 4D spacetime is a low dimensional deterministic model. Determinism might exist at the macro level except for the human brain where nobody knows what it's going to come up with.
Seeker2
1 / 5 (1) Jan 02, 2012
The objects will not move in space, it is the space that is expanding. That's the truth.
Nope - the truth is, the remote objects appear reddish with distance. Everything else is speculation. There are two main possible explanation: the Doppler shift of the light wavelength due the omnidirectional expansion of space...
I looks like we're first saying space is not expanding (Nope) but then the Doppler shift is due to expansion of space. Which is it?
Seeker2
1 / 5 (1) Jan 02, 2012
Also the event was the beginning of what we call spacetime. So you can't really look further back because there is no 'further back' in time.
I think the beginning of spacetime occurred when the laws of nature were first enacted.
Seeker2
1 / 5 (2) Jan 02, 2012
So it is only between these bound systems that space expands.
I'd think space is expanding everywhere. Within bound systems objects (galaxies) are falling into and being recycled back to radiation by black holes, which I assume will bring spacetime back to a lower energy level and make it flatter. I assume flatter means more uniform. Actually as space expands the curvature of spacetime decreases resulting in less gravity, but as long as there still is gravity the bound systems will contract (since that's what gravity does) and I don't believe expansion will overcome this contraction. Expansion is another means for spacetime to cool down until it reaches near absolute zero, at which time I think electrostatic attraction between surviving electrons and positrons at the outer edges of spacetime takes over and spacetime begins contraction. So go ahead and call me crazy if you want.

Callippo
1 / 5 (1) Jan 02, 2012
but as long as there still is gravity the bound systems will contract and I don't believe expansion will overcome this contraction
What you believe in is irrelevant. What's worse, your hypothesis doesn't explain, why space-time expansion accelerates - on the contrary: by your model the space-time should slow down already. Whereas in existing L-CDM model the Universe expanded first in inflation, then it's expansion suddenly slowed down and now its speed increases again. IMO your level of thinking cannot provide explanation even for this complicated past, not to say about some predictions of its further evolution. You should learn a bit about AWT instead...;-)
Seeker2
1 / 5 (2) Jan 02, 2012
cont...
Actually I think surviving electrons aggregate in an inner shell in the denser parts of spacetime where their gravitational attraction is balanced by their electrostatic repulsion. Positrons are similarly configured in an outer shell where their gravitational attraction balances their mutual repulsion. Note positrons are not attracted by gravity until spacetime expands so much that its energy density is less than that of the positron's. Well I can get into more cyclic U theory but I think that should be enough conjecture for right now. Except for one thing: If expansion reduces the curvature of spacetime and gravity I should think it would reduce all other forces so if any molecules should escape the black holes they would fall apart. But I still have some more thinking to do on that one.
Seeker2
1 / 5 (1) Jan 02, 2012
What you believe in is irrelevant.
Then don't worry about it.

What's worse, your hypothesis doesn't explain, why space-time expansion accelerates - on the contrary: by your model the space-time should slow down already.
Well how could I do that? According to Newton's second law as long as there is a force acting on something it will accelerate. So if the U is expanding because of some force then it will continue to accelerate. I assume there is some force out there (the quintessential 5th force) causing expansion - the internal energy of spacetime. This force acting over a distance performs work. Work requires energy - the dark energy I presume. If this energy is finite then accelerated expansion will stop when the energy runs out. At this point the temperature of the U will probably be near zero and the attractive electrostatic forces which I discussed in the previous post will take over.
Callippo
1 / 5 (2) Jan 02, 2012
But I still have some more thinking to do on that one..
The expansion of space-time is not redistribution of some particles in it.
If expansion reduces the curvature of spacetime and gravity I should think it would reduce all other forces
It apparently doesn't, because the space-time expands, but the size of galaxies not. Actually, the galaxies are shrinking instead, which would indicate, the forces between particles increase instead. http://arxiv.org/abs/1011.4956 Actually you've no chance to solve it with concept of space-time expansion.
Callippo
1 / 5 (1) Jan 02, 2012
Then don't worry about it.
Then don't care about my worrying. The belief doesn't require some agreement or feedback, being self assuring.
So if the U is expanding because of some force then it will continue to accelerate...If this energy is finite then accelerated expansion will stop when the energy runs out.
Once again, L-CDM model is about expansion of space-time, not about bouncing of some particles inside of static space-time. And once again, this model doesn't explain, why Universe expanded fast, then slowly, then faster again, as we experience by now. Your model just implies bouncing back and forth.
Callippo
1 / 5 (2) Jan 02, 2012
Positrons are similarly configured in an outer shell where their gravitational attraction balances their mutual repulsion.
Which outer shell? There is no outer shell of Universe expansion in Big Bang or cyclic cosmology.
Seeker2
1 / 5 (1) Jan 02, 2012
Positrons are similarly configured in an outer shell where their gravitational attraction balances their mutual repulsion.
Which outer shell? There is no outer shell of Universe expansion in Big Bang or cyclic cosmology.
I'm referring to the circular patterns found by Penrose and company in the CMBR. There seems to be some debate about this among cosmologists. I'm just putting my spin on it. Hope you don't find it offensive.
Seeker2
1 / 5 (1) Jan 02, 2012
And once again, this model doesn't explain, why Universe expanded fast, then slowly, then faster again,...
If you're smart enough to ask this question I'd think you'd also know the answer. So as I suspect you know the early expansion was slowed down by gravitational forces experienced by the creation of matter. This force was eventually overcome and expansion resumed its previous rate. I don't think this rate will continue though as the dark energy is depleted. I wouldn't expect to be around when this happens though.
Seeker2
1 / 5 (1) Jan 02, 2012
Then don't worry about it.
Then don't care about my worrying.
Hey no problem. I wonder if they award PHDs in rhetoric nowadays.

The belief doesn't require some agreement or feedback, being self assuring.
So we should believe whatever gives us self-assurance and don't ask questions. Sounds sort of like feel-good religion.

Once again, L-CDM model is about expansion of space-time,
Wow. You're way ahead of me on that one. I'll have to check it out. It does seem a bit off-topic though.

not about bouncing of some particles inside of static space-time.
Did I say something about that? Sorry. BTW are you promoting the idea of static spacetime?
Seeker2
1.5 / 5 (2) Jan 02, 2012
The expansion of space-time is not redistribution of some particles in it.
Certainly not.

Actually, the galaxies are shrinking instead, which would indicate, the forces between particles increase instead. http://arxiv.org/abs/1011.4956 Actually you've no chance to solve it with concept of space-time expansion
Certainly not. The closer particles come the greater the force of gravity between them. If the expansion force of spacetime was greater than gravity I'd be flying off my chair right now.
Fleetfoot
not rated yet Jan 02, 2012
How far away will the matter we are made of, have moved? Calculated by the now accepted expansion of the universe?

The matter we are made of, can hardly have moved 13.5 billion light years over 13.5 billion years, just as light has done it?


The matter here was formed here, it hasn't moved (other than some minor local proper motion). The matter "over there" which emitted the light from the most distant galaxies we can see was formed "over there", it hasn't moved either. The gap between "there" and "here" has increased during the time the light was travelling.

There is something rotten in the state of the Universe. (Adapted from William Shakespeare's "Hamlet")


No, only in your understanding of it. ;-)

Have a Happy New Year.
Fleetfoot
not rated yet Jan 02, 2012
And once again, this model doesn't explain, why Universe expanded fast, then slowly, then faster again,...
If you're smart enough to ask this question I'd think you'd also know the answer. So as I suspect you know the early expansion was slowed down by gravitational forces experienced by the creation of matter.


I think Calippo was referring to the early inflationary period suggested to explain the uniformity of the CMBR. The details of that are not yet understood.

This force was eventually overcome and expansion resumed its previous rate.

That is correct for the subsequent expansion.

I don't think this rate will continue though as the dark energy is depleted. I wouldn't expect to be around when this happens though.


If it is actually a cosmological constant as measurement seems to be confirming, it also acts as a negative pressure which means the total energy is conserved so the expansion becomes exponential with time.
Callippo
1 / 5 (2) Jan 02, 2012
I suspect you know the early expansion was slowed down by gravitational forces experienced by the creation of matter.
You're basically saying, the mixture of photons which are materializing mutually has different mass, than the mass of matter, formed with such materialization. You're apparently considering space-time fixed and the only visible matter undergoes in it the cyclic evolution (a bouncing). Such a model would lead into inhomogeneous universe - some matter in distant areas of Universe would appear more dense in this direction, i.e. the Universe wouldn't be isotropic in this model anymore. And we should ask, why the Universe should keep the synchronization of phases of bouncing and collapsing of matter across different areas. If you can admit it, then you're essentially describing the AWT cosmology.
Callippo
1 / 5 (2) Jan 02, 2012
The expansion of space-time is not redistribution of some particles in it. Certainly not.
Such an answer can be interpreted in both ways...;-) Do you agree with it or not?
LarsKristensen
1 / 5 (1) Jan 02, 2012
The matter here was formed here, it hasn't moved (other than some minor local proper motion). The matter "over there" which emitted the light from the most distant galaxies we can see was formed "over there", it hasn't moved either. The gap between "there" and "here" has increased during the time the light was travelling.


I know the explanation, but the problem is. The space where our matter is located, has expanded at a lower speed than light has traveled by. The light can probably not come rushing after the expanding space.

We can hardly be in an expansion by a speed greater than the speed of light. Are we that, we would not be able to see the young universe.
Seeker2
1 / 5 (2) Jan 02, 2012
The expansion of space-time is not redistribution of some particles in it. Certainly not.
Such an answer can be interpreted in both ways...;-) Do you agree with it or not?
Yes I agree particles are not being redistributed with spacetime expansion.
Seeker2
1 / 5 (1) Jan 02, 2012
The light can probably not come rushing after the expanding space.
Certainly not. Light travels right along with expanding space.

We can hardly be in an expansion by a speed greater than the speed of light. Are we that, we would not be able to see the young universe.
I think we would if we were traveling right along with the expanding U. Anyway I did my homework tonight and found per http://en.wikiped...universe the current radius of the U is 14 mpc which would represent an expansion speed for the farthest reaches of the U of about 1/3 the speed of light assuming the Hubble constant is 71km/sec/mpc. But I don't provide any assurance of getting correct results for freebie consultation services.
Seeker2
1 / 5 (2) Jan 02, 2012
You're apparently considering space-time fixed and the only visible matter undergoes in it the cyclic evolution (a bouncing).
Yes I think matter comes and goes, except maybe the leptons. Spacetime certainly is fixed in space and time as far as its center of mass and time is concerned, but the expansion and contraction would be cyclical (bouncing, as you say. Actually probably more like the beating of a living heart. This would make the U actually a living being.)
Seeker2
1 / 5 (2) Jan 03, 2012
The expansion of space-time is not redistribution of some particles in it. Certainly not.
Such an answer can be interpreted in both ways...;-) Do you agree with it or not?
Yes I agree particles are not being redistributed with spacetime expansion.
So a photon's wavelength is not re-distributed in spacetime expansion, only stretched. An interesting logical consequence is that any molecules existing billions of years ago will also be stretched. But we don't observe any such molecules so I presume they have been ripped apart. Similarly the molecules we observe now will eventually be ripped apart. This doesn't mean there won't be any molecules in the distant future, they will just have to be reformulated.
rawa1
1 / 5 (2) Jan 03, 2012
Spacetime certainly is fixed in space and time as far as its center of mass and time is concerned, but the expansion and contraction would be cyclical So a photon's wavelength is not re-distributed in spacetime expansion, only stretched.
It's still not clear, what are you talking about. Is in your model the space-time FIXED and particles of matter are moving in it from place to place - or do you consider the space-time expansion (and/or contraction) during Universe evolution in the same way, like mainstream L-CDM model?
Seeker2
1 / 5 (2) Jan 03, 2012
It's still not clear, what are you talking about. Is in your model the space-time FIXED and particles of matter are moving in it from place to place - or do you consider the space-time expansion (and/or contraction) during Universe evolution in the same way, like mainstream L-CDM model?
Actually no the center of mass of spacetime is not fixed, only not being accelerated. If it were there would have to be an external force which should also be considered part of the U. I used to think the universe was in free fall but I think objects in free fall are being accelerated. I don't think the natural laws of the universe evolve, if that's what you mean by evolution. I guess some people do though, based on the very good point that how else would the natural laws come about. But I don't see how evolution could occur in the Darwinian sense. Due to the uncertainty principle there is an infinite number of possible scenarios for each cycle. But some people say there is an infinite number...
Seeker2
1 / 5 (1) Jan 03, 2012
cont
of universes, so exact similar scenarios must occur multiple times, in fact, an infinite number of times. So we have an indeterminate fraction of this possiblity - infinite/infinite. In this case I'd have to pull out Occam's razor and say why would nature want to repeat the same scenario? So no I don't think there are exactly repeating scenarios, if that's what you mean by evolution.
Fleetfoot
not rated yet Jan 03, 2012
... the problem is. The space where our matter is located, has expanded at a lower speed than light has traveled by.


You cannot meanignfully describe expansion by a speed without reference to the distance, think of it as a fractional change, for example Hubble distances have increased by about 1% in the last 200 million years.

The light can probably not come rushing after the expanding space.


That is exactly what it does. From the point of view of the galaxy from which the light was emitted, we are moving away and the light is chasing after us. If you imagine the space between filled with specks of dust,the light passes each at speed c.

We can hardly be in an expansion by a speed greater than the speed of light. Are we that, we would not be able to see the young universe.


What you mean is not clear to me but we can see out to a redshift of about 7 and the distance between us and a galaxy at a redshift of about 1 is increasing at one light year per year.
Fleetfoot
not rated yet Jan 03, 2012
Anyway I did my homework tonight and found per http://en.wikiped...universe the current radius of the U is 14 mpc


That should be 14 GPc, not MPc.

which would represent an expansion speed for the farthest reaches of the U of about 1/3 the speed of light assuming the Hubble constant is 71km/sec/mpc. But I don't provide any assurance of getting correct results for freebie consultation services.


It isn't that easy because the Hubble constant was much higher in the past (it is only constant over space, not time) and the source galaxy was much closer.
Seeker2
1 / 5 (2) Jan 03, 2012
If it is actually a cosmological constant as measurement seems to be confirming, it also acts as a negative pressure which means the total energy is conserved so the expansion becomes exponential with time.
Yes this would support the one-shot big bang theory, not the cyclic theory. Perhaps there is a sleeper in there, however. I think in the creation of matter/antimatter the antimatter has less energy density than spacetime so it bubbles up to the fringes of space. Because of its mutual electrostatic repulsion it begins to form a symmetrical shell around the expanding space. When spacetime expands enough so that its energy density becomes less dense than that of antimatter, antimatter becomes gravitationally attractive. That is its shell begins to contract and space becomes gravitationally bound. In the meantime electrons have collected in a symmetrical inner shell. The electrostatic force of attraction between the inner and outer shells then begins the collapsing phase.
Seeker2
1 / 5 (1) Jan 03, 2012
cont...
Actually the shells idea comes from my take on the images seen by Penrose and company in the CMBR.
Fleetfoot
not rated yet Jan 03, 2012
Cyclic theories are severely constrained by observation, dark energy will cause the expansion to become exponential (the Hubble constant actually becomes constant over time) so the density falls asymptotically towards zero.

I think in the creation of matter/antimatter the antimatter has less energy density than spacetime ..


Density is energy divided by volume so "less density than spacetime" is not a phrase that means anything to me.

the fringes of space.


The distribution of matter and antimatter would always have been uniform everywhere, there are no "fringes of space". Many tests have confirmed the Cosmological Principle.

Because of its mutual electrostatic repulsion


Again that makes no sense, positrons and protons are positive while electrons and anti-protons are negative so why would they repel?

The rings reported in the CMBR are not shells, they would be like ripples in a pool but recent checks have pretty much ruled them out as statistical artefacts.
Fleetfoot
not rated yet Jan 03, 2012
Regarding energy density, you might find this interesting:

http://www.univer...ventory/

Bedtime for me now...
Seeker2
1 / 5 (1) Jan 03, 2012
...they would be like ripples in a pool...
More AWT theory? Like Genesis 1 updated?
Seeker2
1 / 5 (2) Jan 03, 2012
Density is energy divided by volume so "less density than spacetime" is not a phrase that means anything to me.
Think of spacetime as a pool (of dark energy). Denser objects sink. Lighter objects rise. Quark matter/antimatter is created in pairs, one having a higher energy density and one a lower density so that the total particle energy plus dark energy is conserved. It's like you rob Peter (antimatter) to pay Paul (matter). Ultimately quark matter sinks into black holes and antimatter rises to the less dense regions of spacetime. So pair production is simply the reconfiguration of dark energy in some region of spacetime.
Seeker2
1 / 5 (2) Jan 03, 2012
Again that makes no sense, positrons and protons are positive while electrons and anti-protons are negative so why would they repel?
Positrons repel positrons in the outer shell. They populate regions of similar density in spacetime but their electrostatic repulsion forces them into a symmetrical configuration (shell). Electrons repel electrons in the inner shell, also forcing them into a symmetrical configuration. They inhabit the denser inner regions of spacetime. Now the attractive electrostatic forces come into play as the two shells attract each other with spacetime trapped inbetween. This pressure increases until the shells break and spacetime is released (inflation). Now the oppositely charged particles are free to annihilate, releasing all the stored energy of positrons and electrons in the U. End of contraction, resume the expansion phase.
Seeker2
1 / 5 (1) Jan 03, 2012
The rings reported in the CMBR are not shells, they would be like ripples in a pool but recent checks have pretty much ruled them out as as statistical artefacts.
The rings are projections of shells as they appear in 2 dimensions to the observer. They are statistical anomalies in the CMBR variance. That is the probability of occurrence of this anomaly as a random effect is basically nil.
Seeker2
1 / 5 (1) Jan 04, 2012
...dark energy will cause the expansion to become exponential (the Hubble constant actually becomes constant over time) so the density falls asymptotically towards zero.
True until its energy density becomes less than that of antimatter inhabiting the less dense regions of spacetime, in which case antimatter becomes gravitationally attractive, spacetime becomes gravitationally bounded, and the collapsing phase begins. The more space expands the heavier antimatter becomes and the stronger the gravitational forces of collapse become. The longer the collapse continues the stronger the attractive electrostatic forces become, accelerating the collapse even faster. Yes beddie bye time sounds good to me too.

Seeker2
1 / 5 (1) Jan 04, 2012
...dark energy will cause the expansion to become exponential (the Hubble constant actually becomes constant over time) so the density falls asymptotically towards zero.
Brings up a good point. Since the expansion becomes exponential in time I would think it would also become exponential in space. That is, there are no walls out there.

Seeker2
1 / 5 (2) Jan 04, 2012
The rings are projections of shells as they appear in 2 dimensions to the observer.
The amazing thing is that they appear as rings from whatever direction you view the CMBR. So they would also appear as rings to every observer in the universe. So if you add up all these 2 dimensional views from every direction you must get a shell.
So nature shares her secrets with all observers in the U. It's amazing what you can see by just looking.

Seeker2
1 / 5 (2) Jan 04, 2012
...dark energy will cause the expansion to become exponential (the Hubble constant actually becomes constant over time) so the density falls asymptotically towards zero.
True until...
Actually not true. Dark energy causes the acceleration of the expansion rate to decrease exponentially. When the dark energy runs out expansion continues at a constant rate until a counterforce comes into play. That happens when the energy density in the far reaches of spacetime becomes less than that of the antimatter collected in the outer shell. This shell begins to contract as antimatter becomes gravitationally attractive and spacetime becomes gravitationally bounded.
Seeker2
1 / 5 (1) Jan 04, 2012
Brings up a good point. Since the expansion becomes exponential in time I would think it would also become exponential in space. That is, there are no walls out there.
Probably true about the walls. I don't think the expansion becomes exponential in time or space. It continues at a constant rate after the dark energy runs out. Do you find this exponential stuff in textbooks? Maybe time for a rewrite.
Seeker2
1 / 5 (2) Jan 04, 2012
The rings are projections of shells as they appear in 2 dimensions to the observer. They are statistical anomalies in the CMBR variance.
Actually they are regions of statistically significant lower CMBR variance. This means to me a more uniform distribution of the source emitters, as in the inner and outer shells.
Seeker2
1 / 5 (1) Jan 04, 2012
Anyway I did my homework tonight and found per http://en.wikiped...universe the current radius of the U is 14 mpc
That should be 14 GPc, not MPc. Correct. To make things worse as I remember I actually used 14 bpc. So the correct answer would be over 300 times the speed of light at the present time. That would be moving right along. So I guess if you want to get it right see a professional.

It isn't that easy because the Hubble constant was much higher in the past (it is only constant over space, not time)
but... I thought the expansion rate was increasing at an accelerating rate? I was only intending to calculate the expansion rate at the present time.

and the source galaxy was much closer
Not sure what that means.
Seeker2
1 / 5 (2) Jan 04, 2012
Brings up a good point. Since the expansion becomes exponential in time I would think it would also become exponential in space. That is, there are no walls out there.
Probably true about the walls. I don't think the expansion becomes exponential in time or space. It continues at a constant rate after the dark energy runs out.
Well I guess technically it doesn't run out, it only decreases exponentially so that expansion continues at an increasingly more constant rate. Sorry about the wisecracks.

Fleetfoot
not rated yet Jan 04, 2012
With 11 post to reply to,I may not have time tonight!

...they would be like ripples in a pool...
More AWT theory? Like Genesis 1 updated?


Google came up with "Aether Wave theory" for AWT so I guess that's what you mean. I hadn't heard of it before and I've been studying cosmology for more than a decade (just as a layman though). From what I've read today, it's just crank nonsense.

I was talking of simple compression waves in the hydrogen/helium plasma that radiated what we see as the CMBR. If Penrose's observations had been correct, that is what they would represent.
Fleetfoot
not rated yet Jan 04, 2012
...dark energy will cause the expansion to become exponential (the Hubble constant actually becomes constant over time) so the density falls asymptotically towards zero.
True until...
Actually not true. Dark energy causes the acceleration of the expansion rate to decrease exponentially. When the dark energy runs out expansion continues at a constant rate ...

I don't think the expansion becomes exponential in time or space. It continues at a constant rate after the dark energy runs out. Do you find this exponential stuff in textbooks? Maybe time for a rewrite.


Expansion has been known about since the late 1920's and Hubble's observations and it was assumed that it would be decreasing due to gravity as you say. At the end of the 1990's new telescopes allowed Perlmutter to measure supernovae at much greater distances and to everyone's surprise he found the expansion was speeding up. Textbooks give us maths which can describe that depending on the cause:
Fleetfoot
not rated yet Jan 04, 2012
The maths is simplest to handle as the "equation of state" which relates pressure to energy density:
http://en.wikiped...smology)
If the cause was some form of energy distributed throughout space which became less dense as space expands, w would have the value -1/3 and the acceleration would slow but would have been higher in the past. If on the other hand it comes from an intrinsic property of the vacuum, then as space expands, each cubic metre always generates the same effect. In that case w=-1 and the expansion increases exponentially.
The data from the WMAP probe combined with other measurements has tied down the value fairly accurately in the last few years:
http://en.wikiped...d_models
w = -0.980 /- 0.053
It looks very strongly as though w=-1 is right.
Perhaps it will help if I point out it is the same as the energy behind the Casimir Effect which has been measured in the lab:
http://en.wikiped...r_Effect
Fleetfoot
not rated yet Jan 04, 2012
w = -0.980 /- 0.053


That should read w = -0.980 plus/minus 0.053

so between -1.033 and -0.927 with 68% confidence (1 sigma).

It seems to be impossible to get the plus sign into the page!
Fleetfoot
not rated yet Jan 04, 2012
That should be 14 GPc, not MPc.
Correct. To make things worse as I remember I actually used 14 bpc. So the correct answer would be over 300 times the speed of light at the present time.

The light was emitted a long time ago.
It isn't that easy because the Hubble constant was much higher in the past
I thought the expansion rate was increasing at an accelerating rate?

It is, but the Hubble constant is the ratio of speed to distance.
I was only intending to calculate the expansion rate at the present time.

The rate of expansion is currently about 1% per 200 million years, but you can't express that as a speed without selecting a distance and the light wasn't emitted here so what does your 300c mean?
and the source galaxy was much closer
Not sure what that means.

To get the speed of the source, you need to multiply the distance to the source when the light was emitted by the Hubble Constantat that time, not now. Both are varying.
Seeker2
1 / 5 (2) Jan 04, 2012
It seems to be impossible to get the plus sign into the page!
I'll second that.
Fleetfoot
5 / 5 (1) Jan 04, 2012
The rings reported in the CMBR are not shells, they would be like ripples in a pool but recent checks have pretty much ruled them out as as statistical artefacts.
The rings are projections of shells as they appear in 2 dimensions to the observer. They are statistical anomalies in the CMBR variance. That is the probability of occurrence of this anomaly as a random effect is basically nil.


Actually, the probability is about 100%, that's the problem with their claim. For example see this summary of the criticisms:

http://www.nature...665.html

or here

http://telescoper...niverse/

There will be a lot of traffic but basically, they misunderstood the statitics of the CMBR, the circles are entirely expected in the randomness and mean nothing.
Seeker2
1 / 5 (2) Jan 04, 2012
To get the speed of the source, you need to multiply the distance to the source when the light was emitted by the Hubble Constantat that time, not now.
I was only trying to find the expansion rate for whatever might be out there at 14mpc which should have been 14gpc as you noted.
Seeker2
1 / 5 (2) Jan 04, 2012
With 11 post to reply to...
Welcome to our site. Did you volunteer for this assignment?

I've been studying cosmology for more than a decade
Sounds like if somebody gave you this assignment they made an excellent selection.

From what I've read today, it's just crank nonsense. Google came up with "Aether Wave theory" for AWT so I guess that's what you mean.
Yes we have some (or maybe a) proponent at this site.
LarsKristensen
1 / 5 (2) Jan 04, 2012
The light can probably not come rushing after the expanding space.


That is exactly what it does. From the point of view of the galaxy from which the light was emitted, we are moving away and the light is chasing after us. If you imagine the space between filled with specks of dust,the light passes each at speed c.


The light there was sent out at the dawn of time, just after the Big Bang, that light, we will never ever come to see, because that was sent out at a time when our particulate matter were very close to all the other particulate matter, who sent the light. The light has long since left us and would never ever come back again. There is a limit to how far back after the Big Bang we can see light coming from. This limit is hundreds of millions of years and therefore also light-years.

Therefore the universe can not be a big bang created universe and expands. We see precisely the light coming much too far away.
Seeker2
1 / 5 (2) Jan 04, 2012
I was talking of simple compression waves in the hydrogen/helium plasma that radiated what we see as the CMBR. If Penrose's observations had been correct, that is what they would represent
Simple compression waves would emanate from spacetime compressed between the two shells which he observes. His idea about colliding black holes seems unlikely because of the unique concentricity of these circles. The black holes would have to be aligned perfectly with the observer to make these concentric circles. Not very likely I would think. I like my take on this much better.

As to the question of whether these circles are statistically significant I'd like to see any other similar or other unique patterns existing in the CMBR. But even if they're not statistically meaningful they apparently do exist and fit my ideas about their purpose.
Seeker2
1 / 5 (2) Jan 04, 2012
cont...
If the circles actually don't exist we would have a case of fraud and I don't think Her Majesty would be very happy about that. She has another more serious problem on her hands right now. BTW thanks for the links.
Seeker2
1 / 5 (2) Jan 04, 2012
Per http://arxiv.org/abs/1012.1486 " the low variance circles occur in concentric families, and this key fact cannot be explained as a purely random effect."
My point exactly. But I still don't see the colliding black hole idea as being very plausible.
"It is, however a clear prediction of conformal cyclic cosmology." I like this idea on fermions but not about infinite expansion.
Fleetfoot
not rated yet Jan 04, 2012
To get the speed of the source, you need to multiply the distance to the source when the light was emitted by the Hubble Constantat that time, not now.
I was only trying to find the expansion rate for whatever might be out there at 14mpc which should have been 14gpc as you noted.


OK,but why not calculate 140 GPC or 1400 GPC, it's just an arbitrary number. Just because that material happened to emit some light a long time ago which we can see now doesn't make it special other than for us.
cont...
If the circles actually don't exist we would have a case of fraud and I don't think Her Majesty would be very happy about that. She has another more serious problem on her hands right now. BTW thanks for the links.

Fleetfoot
not rated yet Jan 04, 2012
With 11 post to reply to...
Welcome to our site. Did you volunteer for this assignment?

I've been studying cosmology for more than a decade
Sounds like if somebody gave you this assignment they made an excellent selection.


No, somebody posted a link to the article in a cosmology forum on Facebook and I just thought I'd respond to some of the misunderstandings

http://www.facebo...7490267/
Fleetfoot
not rated yet Jan 04, 2012
The light there was sent out at the dawn of time, just after the Big Bang, that light, we will never ever come to see, because that was sent out at a time when our particulate matter were very close to all the other particulate matter, who sent the light. ... There is a limit to how far back after the Big Bang we can see light coming from. This limit is hundreds of millions of years and therefore also light-years.


The farthest we can see using EM (light) is the CMBR. Using mean figures, that has a redshift of 1090. It was emitted 378,000 years after the start at a distance of some 41 million light years from us. It was at a maximum distance of about 6 billion light years from us about 9 billion years ago because the space between us and it was expanding faster than it was moving towards us. After that though, as the Hubble Constant reduced, it was able to catch up to us. You can work it out on a simple spreadsheet.
Fleetfoot
not rated yet Jan 04, 2012
As to the question of whether these circles are statistically significant I'd like to see any other similar or other unique patterns existing in the CMBR. But even if they're not statistically meaningful they apparently do exist and fit my ideas about their purpose.


One of the subsequent papers searched for perfect equilateral tringles and found several. Pick a shape and it's probably there. That's the problem, the statistical nature of the CMBR means false detections are highly likely. I'll try to find a reference tomorrow to another paper I know of which is much more professional and virtually rules out such signals.
yyz
4 / 5 (1) Jan 04, 2012
"One of the subsequent papers searched for perfect equilateral tringles and found several."

You're previous link to the article in Nature has a link to this paper by Moss et al: http://arxiv.org/...05v3.pdf

Two additional critiques of the original Gurzadyan and Penrose paper ( http://arxiv.org/...3706.pdf ) are also noted:

http://arxiv.org/...56v1.pdf

http://arxiv.org/...68v1.pdf

A response to these critiques has also been posted: http://arxiv.org/...1486.pdf

For myself I'm still not convinced of the significance of G & P's "discovery" and, as the Nature article points out, even Gurzadyan admits "....he is not prepared to state that the circles constitute evidence of Penrose's model. "We have found some signatures that carry properties predicted by the model"".
Seeker2
1.5 / 5 (4) Jan 05, 2012
Great references. But nobody explicitly tests the hypothesis about a family of circles as far as I see right now, but maybe I missed something. For there to be a family of concentric circles the key statistic would be the variance of the region between the individual circles compared to that of the bordering circles. So we need to know exactly what pixels are included in the concentric rings and the pixels between the two rings, and the variance values for all these pixels. This would be the easist way to disprove the hypothesis. It looks like some of these analyses didn't group all the data and did separate analyses for each band or instrument. This seriously reduces the sensitivity of the tests. It seems like a simple F test could be applied before doing all these fancy simulations without grouping all the data.
Seeker2
1 / 5 (2) Jan 05, 2012
The distribution of matter and antimatter would always have been uniform everywhere,
Assuming homogeneity on the global scale at the present time perhaps.

there are no "fringes of space".
I misused the term, but note Fleetfoot points out the exponential distribution of space expansion. So perhaps spacetime and its energy density is also exponentially distributed.

I think in the creation of matter/antimatter the antimatter has less energy density than spacetime so it bubbles up to the fringes of space.
Yes I think antimatter has less energy density than matter but all objects in spacetime seek regions of space having a similar energy density, meaning antimatter in less dense regions and matter in more dense regions. Like a submarine diving or surfacing. Or so it would seem.
Seeker2
1 / 5 (2) Jan 05, 2012
It seems like a simple F test could be applied before doing all these fancy simulations without grouping all the data.
Make that a chi-squared test. It's been a while.
Fleetfoot
not rated yet Jan 06, 2012
Make that a chi-squared test. It's been a while.


That might work if the noise spectrum were flat but it is far from it:

http://map.gsfc.n...dex.html

The peaks mean there are intrinsic resonances which will create patterns. Since there may be non-linearities involved, it is possible that peaks of a fundamental could coincide with those of its harmonics which would approximate conentric "families". The analysis needs to take that into account and so tests will be much more complex. For example considering whether the commonality of the centres of circles with harmonically related radii is more than would be expected given the power spectrum.
Fleetfoot
not rated yet Jan 06, 2012
The distribution of matter and antimatter would always have been uniform everywhere,
Assuming homogeneity on the global scale at the present time perhaps.


Yes, it assumes the CosmologicalPrinciple:

http://en.wikiped...rinciple

It is hard to test homogeneity radially but many tests have confirmed that the universe is isotropic from our location so that reduces the assumption to the Copernican Principle:

http://en.wikiped...rinciple

If the principle applies now then expansion is also isotropic so it would apply at all times, past and future of course.
Fleetfoot
not rated yet Jan 06, 2012
Fleetfoot points out the exponential distribution of space expansion.


No, I said the rate becomes exponential as the matter becomes very dilute, the distribution is isotropic.

I think antimatter has less energy density than matter ..


Equivalent matter and antimatter particles have the same mass.

Neither has an energy density on its own. Mass is one form of energy and energy density is just the total mass divided by the volume in which it is found. Just add up all the mass you find in one cubic metre of space, multiply by c^2, and you have the energy density. You need to average over many clusters of galaxies in cosmology of course.

but all objects in spacetime seek regions of space having a similar energy density, meaning antimatter in less dense regions and matter in more dense regions. Like a submarine diving or surfacing. Or so it would seem.


Sorry but that's nonsense, energy density is an average over a large volume.
Seeker2
1 / 5 (2) Jan 06, 2012
Sorry but that's nonsense, energy density is an average over a large volume
Energy density is the total energy per unit volume, large, small, or otherwise.
Seeker2
1 / 5 (2) Jan 06, 2012
I think antimatter has less energy density than matter ..
Equivalent matter and antimatter particles have the same mass.
Ergo, the same energy.

Neither has an energy density on its own.
Alas, as I see it each element of spacetime has a nominal energy (call it E) and a nominal energy density, but quantum fluctuations move the borders around between adjacent elements. You can get off at this STOP if you never heard of quantized spacetime. Hence quantum fluctuations are fluctuaions of energy density. If these fluctuations form one of the configurations allowed by QM or string theory or whatever they become locked in by gluons (think of them as elements of a template) to form a particle-antiparticle pair.
Seeker2
1 / 5 (2) Jan 06, 2012
cont...
So the uncertainty principal robs Peter to pay Paul in the sense that it moves the borders so initially if Peter and Paul each occupied a volume of 2, say, the quantum fluctuations move the border between them so now Peter occupies a volume of 1 and Paul a volume of 3. Same total energy (2E), same total volume (4), just a bit of energy density redistribution you might say. So now Peter has an energy density of E/1 (E) and Paul E/3. Voila. Paul gets the short end of the stick. He will have to move into a neighborhood with lower energy density and Peter will get promoted to the higher density neighborhoods (like a black hole, the poor sucker).
Seeker2
1 / 5 (2) Jan 07, 2012

http://map.gsfc.nasa.gov/resources/camb_tool/index.html

Neat site. I got the red line covered except for a little red uptick on the far right end.

The peaks mean there are intrinsic resonances which will create patterns. Since there may be non-linearities involved, it is possible that peaks of a fundamental could coincide with those of its harmonics which would approximate conentric "families". The analysis needs to take that into account and so tests will be much more complex. For example considering whether the commonality of the centres of circles with harmonically related radii is more than would be expected given the power spectrum
Good points. You would need to know the expected value at each pixel and calculate a variance around those expected values.
Seeker2
1 / 5 (2) Jan 07, 2012
cont...
So the uncertainty principal
Sorry, maybe principle, guess I just wasn't certain.
Fleetfoot
not rated yet Jan 07, 2012
I think antimatter has less energy density than matter ..
Equivalent matter and antimatter particles have the same mass.
Ergo, the same energy.

Neither has an energy density on its own.
Alas, as I see it each element of spacetime has a nominal energy (call it E) and a nominal energy density, but quantum fluctuations move the borders around between adjacent elements. You can get off at this STOP if you never heard of quantized spacetime.


I have but I think the Integral observations last year make it very unlikely.
Fleetfoot
not rated yet Jan 07, 2012
cont...
so now Peter occupies a volume of 1 and Paul a volume of 3. Same total energy (2E), same total volume (4), just a bit of energy density redistribution you might say. So now Peter has an energy density of E/1 (E) and Paul E/3. Voila. Paul gets the short end of the stick.


Fine but Peter might be a proton or anti-proton while Paul is the electron or positron, it still wouldn't differentiate matter from antimatter, only families of particles.

He will have to move into a neighborhood with lower energy density and Peter will get promoted to the higher density neighborhoods (like a black hole, the poor sucker).


No, the nearest low-density region is Paul so they would just revert to the original configuration, winking back out of existence as QM says.
Fleetfoot
not rated yet Jan 07, 2012

http://map.gsfc.n...dex.html

Neat site. I got the red line covered except for a little red uptick on the far right end.


There's a button to force the concordance values so you can see what you missed.

Good points. You would need to know the expected value at each pixel and calculate a variance around those expected values.


Using known pixel values assumes the result so instead they
use a Monte Carlo technique to create random maps with the same angular power spectrum and then see how many circle patterns their analysis gives. If the real data shows more than is statistically predicted, then they might have a significant result. Others have done that and the circles seem to be noise.
Fleetfoot
not rated yet Jan 07, 2012
Sorry but that's nonsense, energy density is an average over a large volume
Energy density is the total energy per unit volume, large, small, or otherwise.


Sure but to separate antimatter galaxies from matter galaxies, you've got to move them over astronomical distances. We know there is virtually no antimatter within our Hubble sphere.
Callippo
1 / 5 (2) Jan 07, 2012
We know there is virtually no antimatter within our Hubble sphere
Because "we" don't consider the dark matter, the neutrinos in particular as an antimatter - I mean, not yet.

http://aetherwave...ter.html
Seeker2
1 / 5 (1) Jan 07, 2012
Fine but Peter might be a proton or anti-proton while Paul is the electron or positron, it still wouldn't differentiate matter from antimatter, only families of particles.
Peter and Paul must have the same amount of energy as does each particle and its anti-particle. Different families of particles borrow different amounts of energy from spacetime, but the amount borrowed is the same as the amount lent, or you don't conserve energy.

Seeker2
1 / 5 (2) Jan 07, 2012
We know there is virtually no antimatter within our Hubble sphere
Whatever that is. Anyway there are antiprotons trapped in the inner Van Allen belts. Normally they would be pushed out of higher energy density neighborhoods like around our earth and forced to seek less energy dense neighborhoods. That might take them a long long way away.
Because "we" don't consider the dark matter, the neutrinos in particular as an antimatter - I mean, not yet.
Don't bet the farm on it.

Seeker2
1 / 5 (2) Jan 07, 2012
Sure but to separate antimatter galaxies from matter galaxies, you've got to move them over astronomical distances. We know there is virtually no antimatter within our Hubble sphere
BTW I would say antimatter is mutually repulsive in the visible U. That is it doesn't aggregate. Except when the energy density of the visible U expands to less than the energy density of the lightest antiparticles which are not electrostatically repulsive. Then they begin to aggregate. But I don't think we'll be around to debate the point by that time. Also I don't think space will ever expand to the point where gravity will overcome the electrostatic repulsion of like charges. Ergo charged particle are ejected from around black holes.
Callippo
1 / 5 (1) Jan 07, 2012
I don't think space will ever expand to the point where gravity will overcome the electrostatic repulsion of like charge
Why it should ever overcome it? With expansion of space the strength of gravity just decreases.
Seeker2
1 / 5 (2) Jan 07, 2012
With expansion of space the strength of gravity just decreases.
But the differential energy density increases. The total weight or energy of the U remains the same, just more diluted. Effectively you're at the bottom of a deeper but less dense pool. Oddly it may be that gravity increases because of the greater differential energy density. Something to ponder I guess.
Callippo
1 / 5 (2) Jan 07, 2012
But the differential energy density increases. The total weight or energy of the U remains the same, just more diluted.
So that the "differential energy density" should decrease as well...
Seeker2
1 / 5 (2) Jan 07, 2012
Oddly it may be that gravity increases
Leading, of course, to the big collapse. Forgot about that.
Seeker2
1 / 5 (2) Jan 07, 2012
But the differential energy density increases. The total weight or energy of the U remains the same, just more diluted.
So that the "differential energy density" should decrease as well...
The differential energy density is the difference between the energy density of spacetime and that of whatever you're comparing it with. As the U expands its energy density decreases and as long as it was less than whatever you're comparing it with to start out with it will be even lesser after the expansion. So in this case the differential energy density will increase. If however you're talking about antimatter at the present time the energy differential is decreasing because right now the energy density of antimatter is less than that of spacetime. I remember Penrose saying something about the U becoming confused in the latter times. I think we can see why.
Callippo
1 / 5 (2) Jan 07, 2012
Oddly it may be that gravity increases because of the greater differential energy density.
I still don't see the chain of logics which implies the increase of gravity with spacetime or Universe expansion. It just violates the general relativity, not to say about common sense.
Seeker2
1 / 5 (2) Jan 07, 2012
I still don't see the chain of logics which implies the increase of gravity with spacetime or Universe expansion. It just violates the general relativity,
How so?
not to say about common sense.
Been swimming lately? How far down can you dive?
Callippo
1 / 5 (2) Jan 07, 2012
Well, if space-time expands, the distance between massive objects is increasing and their gravity decreases. How simple - try to disprove it. What has it to do with my alleged swimming?
Seeker2
1 / 5 (2) Jan 07, 2012
Or, have you ever been on an aircraft and felt your ears pop as you gained altitude? That's because of a pressure density gradient between what's in your ears at takeoff and cabin pressure.
Seeker2
1 / 5 (2) Jan 07, 2012
Well, if space-time expands, the distance between massive objects is increasing and their gravity decreases.
Good point but the force of gravity is greater than the force of expansion so gravitational collapse for gravitationally bound objects will continue and the effect of expansion will be miniscule.

How simple - try to disprove it.
Yes it does seem simple but you have to read the fine print.

What has it to do with my alleged swimming?
Actually I meant diving. Another situation where your ears might pop.
Callippo
1 / 5 (2) Jan 07, 2012
but the force of gravity is greater than the force of expansion
Force of expansion? What do you mean with it?
but you have to read the fine print
Which fine print do you mean? I'm not swimming, neither diving, neither see some fine print. What's the actual purpose of your sixty four posts in this thread? IMO you're just daydreaming loudly.
Seeker2
1 / 5 (2) Jan 07, 2012
Force of expansion? What do you mean with it?
I mean the force which causes the acceleration of expansion. I've already expounded on this twice as I remember.

Which fine print do you mean?
The post about the force of gravity being greater than the force of expansion.

What's the actual purpose of your sixty four posts in this thread?
If we didn't have to re-hash the same arguments over and over there wouldn't be so many posts.
Callippo
1 / 5 (2) Jan 07, 2012
Arguments for what?
Seeker2
1 / 5 (2) Jan 07, 2012
Using known pixel values assumes the result...
By "known" you could mean the observed values or you could mean the expected (somebody's best fit) values from the formulas used at http://map.gsfc.n...dex.html. The relevant variance, as I see it, is the difference between these two. If they see circles or any other subsets of pixels with lower than expected variance they should say exactly what these pixels are and what are their expected and observed values. Otherwise we just don't know where they're coming from.
Seeker2
1 / 5 (2) Jan 07, 2012
Arguments for what?
Like your last question about expansion.
Seeker2
1 / 5 (2) Jan 07, 2012
http://map.gsfc.n...dex.html
Neat site. I got the red line covered except for a little red uptick on the far right end.

There's a button to force the concordance values so you can see what you missed.
Got it. Still see that little red uptick at the end of the graph. I wonder if there could be some missing antimatter in this model.
Seeker2
1 / 5 (2) Jan 07, 2012
Also I wonder if the CMBR image can be related to the large scale structure of the U. If so maybe we could find where we came from in the image.
Fleetfoot
not rated yet Jan 09, 2012
We know there is virtually no antimatter within our Hubble sphere
Because "we" don't consider the dark matter, the neutrinos in particular as an antimatter - I mean, not yet.


Because we don't see a huge gamma flux which would result from any significant amount of antimatter.

I don't understand the rest of your comment, anti-neutrinos are commonly produced in particle accelerator experiments and "we" certainly consider them to be antimatter.

Dark matter cannot be neutrinos because they don't have enough rest mass though something like a heavy neutrino is a candidate. Dark matter forms clumps and structures whereas neutrinos with negligible energy move close to the speed of light.
Fleetfoot
not rated yet Jan 09, 2012
Peter and Paul must have the same amount of energy as does each particle and its anti-particle. Different families of particles borrow different amounts of energy from spacetime, but the amount borrowed is the same as the amount lent, or you don't conserve energy.


A box one cubic metre containing Peter and Paul would have the same energy content as the same box empty. Put an electron or positron in it and the energy is increased by 511kEv. I'm not sure what your are suggesting but if I take what you say literally, it doesn't work.

I've realised there has been some confusion because we are using "energy density" in two different ways. In this argument, you seem to use the term to mean the vacuum energy whereas on cosmological scales it refers to the contents of space which create gravitational effects, the two are not the same. That has probably caused some miscommunication previously.
Fleetfoot
not rated yet Jan 09, 2012
We know there is virtually no antimatter within our Hubble sphere
Whatever that is.


My mistake, I meant the observable universe.

Anyway there are antiprotons trapped in the inner Van Allen belts.


The quantity is completely negligible in comparison to the mass of the Solar System and that is typical. Cosmic rays produce small quantities but it is not a significant fraction of the mass of the universe in terms of gravitational effects.
Fleetfoot
not rated yet Jan 09, 2012
BTW I would say antimatter is mutually repulsive in the visible U. That is it doesn't aggregate.


In some accelerators, protons are collided with anti-protons to double the energy available. If the energy of the antiproton was negative, it would reduce the total instead of increasing it. Positive energy means positive curvature so antimatter is identical to matter gravitationally. It's not been confirmed experimentally yet but the success of the group who stored anti-hydrogen for over 1000 seconds last year means it should soon be possible.
Fleetfoot
not rated yet Jan 09, 2012
Also I don't think space will ever expand to the point where gravity will overcome the electrostatic repulsion of like charges. Ergo charged particle are ejected from around black holes.


A positively charged black hole would attract electrons and repel protons and vice versa for a negatively charged BH. Either way, the charge tends to get neutralised. The radiation pressure is far more significant (and not affected by charge) so accretion disc dynamics is a very complex subject.
Fleetfoot
not rated yet Jan 09, 2012
With expansion of space the strength of gravity just decreases.
But the differential energy density increases. The total weight or energy of the U remains the same, just more diluted.


This is where you are confusing energy densities. The total mass of matter (including dark matter but not dark energy) in the observable universe is constant so as it expands, the density falls as you say. That density generates the curvature called gravity so that too falls.

On the other hand, the vacuum energy in any given volume of space is not dependent on scale factor, it appears as an intrinsic property of space, so it is constant (this is what you described with "Peter and Paul"). Since it acts like a repulsive component of gravity, as the universe expands to the point where they effects are equal, the expansion stops slowing and then starts to accelerate. that happened about 7 or 8 billion years ago.
Fleetfoot
not rated yet Jan 09, 2012
Got it. Still see that little red uptick at the end of the graph. I wonder if there could be some missing antimatter in this model.


Matter and antimatter contribute identically, both produce the same gravitational effects. The red tick is at the upper frequency limit or equivalently at the limit of resolution of the sensors. The Planck spacecraft is intended to improve that end of the graph:

http://en.wikiped...cecraft)
Fleetfoot
5 / 5 (1) Jan 09, 2012
Also I wonder if the CMBR image can be related to the large scale structure of the U. If so maybe we could find where we came from in the image.


The usual WMAP image is a Mollweide Projection of the CMBR. The pattern certainly relates to the large scale struture "out there" but it is a surface which is a sphere centered on where we are and always have been.

On the other hand, blobs in the image will have formed into galaxies now 45 billion light years away and scientists in those galaxies will see their CMBR coming from the plasma that later cooled and formed into our galaxy.

As Edwin Harrison said:

Hydrogen is a light, odourless gas, which, given enough time, turns into people."
Seeker2
1 / 5 (2) Jan 10, 2012
A box one cubic metre containing Peter and Paul would have the same energy content as the same box empty. Put an electron or positron in it and the energy is increased by 511kEv.
Ok. So now put them both in it. What do you get then?
Seeker2
1 / 5 (2) Jan 10, 2012
With expansion of space the strength of gravity just decreases.
But the differential energy density increases. The total weight or energy of the U remains the same, just more diluted.


This is where you are confusing energy densities. The total mass of matter (including dark matter but not dark energy) in the observable universe is constant so as it expands, the density falls as you say. That density generates the curvature called gravity so that too falls.
Curvature or gravity inside a gravitationally bound object, such as a galaxy, doesn't change with expansion (supposing the galaxy was not collapsing). To an observer outside the galaxy the galaxy appears to be getting smaller so he thinks its curvature is increasing.
Seeker2
1 / 5 (2) Jan 10, 2012
Also I wonder if the CMBR image can be related to the large scale structure of the U. If so maybe we could find where we came from in the image.


The usual WMAP image is a Mollweide Projection of the CMBR. The pattern certainly relates to the large scale struture "out there" but it is a surface which is a sphere centered on where we are and always have been.
How convenient. We can look out from the center and see the energy patterns all around us, or at least energy patterns of the large scale structures.
Seeker2
1 / 5 (2) Jan 10, 2012
With expansion of space the strength of gravity just decreases.
But the differential energy density increases. The total weight or energy of the U remains the same, just more diluted


This is where you are confusing energy densities. The total mass of matter (including dark matter but not dark energy) in the observable universe is constant so as it expands, the density falls as you say. That density generates the curvature called gravity so that too falls.
"it expands" I guess meaning everything, then in this case our rulers also expand, so it's a wash.
Seeker2
1 / 5 (2) Jan 10, 2012
On the other hand, the vacuum energy in any given volume of space is not dependent on scale factor,...
Ergo the only force involved is when you have a difference in energy density.
Seeker2
1 / 5 (2) Jan 10, 2012
A positively charged black hole would attract electrons and repel protons and vice versa for a negatively charged BH. Either way, the charge tends to get neutralised. The radiation pressure is far more significant (and not affected by charge) so accretion disc dynamics is a very complex subject
Yes well not really that complex. Per http://en.wikiped...ack_hole "it is not expected that black holes with a significant electric charge will be formed in nature."

Seeker2
1 / 5 (2) Jan 10, 2012
Positive energy means positive curvature so antimatter is identical to matter gravitationally.
Antimatter is identical to matter in energy content. But gravitation is caused by a difference in energy density. The energy density of antimatter is less than that of matter as I see it (conservation of spacetime volume at the time of creation). That is pair production doesn't change the total volume of spacetime. Nature is smarter than that. The energy density of antimatter is less than that of spacetime so it floats. Matter sinks, like into black holes. Spacetime acts to mediate the force of gravity. That is without spacetime there is no force of gravity between matter and antimatter. That's why particle pairs normally merge and their energy is returned to the vacuum.
Seeker2
1 / 5 (2) Jan 10, 2012
cont...
Unless the vacuum produces enough of a quantum fluctuation so that spacetime can intervene and separate the particle pair to become real particles, they will remain as virtual particles and merge back into the vacuum. So if matter and antimatter didn't react opposite to each other in the presence of spacetime, there would be no pair production.
Seeker2
1 / 5 (2) Jan 10, 2012
Anyway there are antiprotons trapped in the inner Van Allen belts.

The quantity is completely negligible in comparison to the mass of the Solar System and that is typical. Cosmic rays produce small quantities but it is not a significant fraction of the mass of the universe in terms of gravitational effects.
Not in our neighborhood anyway. Actually I'd say there is nearly an identical amount of antimatter and matter in the U. Antimatter knows its place and it isn't around here in denser energy spacetime. It's out there where the energy density of spacetime is maybe 1/3 to 1/2 the density in our neighborhood. But not to worry, In the end times after all matter has been consumed by the black holes it will eventually become more dense than spacetime and begin to aggregate. I doubt if their energy density will ever be high enough for the sun to ever shine again. But they may form antimatter black holes so their ultimate fate is only delayed.
Seeker2
1 / 5 (2) Jan 10, 2012
In the end times after all matter has been consumed by the black holes it will eventually become more dense than spacetime and begin to aggregate.
"it" intended to refer to antimatter.
Fleetfoot
not rated yet Jan 10, 2012
A box one cubic metre containing Peter and Paul would have the same energy content as the same box empty. Put an electron or positron in it and the energy is increased by 511kEv.
Ok. So now put them both in it. What do you get then?


That's what I said. As you described your idea, the energy in each region doesn't change, only the size, so put a box round both of them and it contains the same total energy as the empty box. Either that or I misunderstood your explanation.
Fleetfoot
not rated yet Jan 10, 2012
With expansion of space the strength of gravity just decreases.
But the differential energy density increases. The total weight or energy of the U remains the same, just more diluted.


This is where you are confusing energy densities. The total mass of matter (including dark matter but not dark energy) in the observable universe is constant so as it expands, the density falls as you say. That density generates the curvature called gravity so that too falls.
Curvature or gravity inside a gravitationally bound object, such as a galaxy, doesn't change with expansion (supposing the galaxy was not collapsing).


Correct, other than normal dynamic processes, it remains unchanged.

To an observer outside the galaxy the galaxy appears to be getting smaller so he thinks its curvature is increasing.


No, an observer far from the galaxy sees it getting farther away but remaining the same size.
Fleetfoot
not rated yet Jan 10, 2012
Also I wonder if the CMBR image can be related to the large scale structure of the U. If so maybe we could find where we came from in the image.


The usual WMAP image is a Mollweide Projection of the CMBR. The pattern certainly relates to the large scale struture "out there" but it is a surface which is a sphere centered on where we are and always have been.
How convenient.


It is hardly surprising, stand in a field on a foggy day when visibility is 100m and the region you can see is a circle of 100m radius centered on you. Move 50m away and the region can see is still a circle of 100m radius centered on your new location. The CMBR works the same way, everyone in the universe can see light that has been travelling for no more than the age of the universe no matter where they are.
Fleetfoot
not rated yet Jan 10, 2012
With expansion of space the strength of gravity just decreases.
But the differential energy density increases. The total weight or energy of the U remains the same, just more diluted


This is where you are confusing energy densities. The total mass of matter (including dark matter but not dark energy) in the observable universe is constant so as it expands, the density falls as you say. That density generates the curvature called gravity so that too falls.
"it expands" I guess meaning everything, then in this case our rulers also expand, so it's a wash.


"it expands" in the context of the quotes means space. This was covered some time ago in thread, rulers are bound by EM forces so don't change.
rawa1
1 / 5 (2) Jan 10, 2012
The CMBR works the same way, everyone in the universe can see light that has been travelling for no more than the age of the universe no matter where they are.
It's AWT model and it implies, Universe can be infinite. Big Bang cosmology says instead, we cannot see farther, because of dark ages period of Universe. In this model you cannot travel along Universe into infinite distance.
Fleetfoot
1 / 5 (1) Jan 10, 2012
On the other hand, the vacuum energy in any given volume of space is not dependent on scale factor,...
Ergo the only force involved is when you have a difference in energy density.


No, what it means is that the contribution from vacuum energy stays the same over time, hence it is a "Cosmological Constant". That doesn't mean it produces no effect, it produces a constant effect.
Fleetfoot
not rated yet Jan 10, 2012
Positive energy means positive curvature so antimatter is identical to matter gravitationally.
Antimatter is identical to matter in energy content.


Exactly.

But gravitation is caused by a difference in energy density.


No, it is caused by the energy density itself, not a difference.

The energy density of antimatter is less than that of matter as I see it


You just agreed that "antimatter is identical to matter in energy content" so put each in a 1 cubic metre box and the energy density is the same too, trivially. For example, whether you put an electron or a positron in a 1m^3 box, the energy density is 511kEv / m^3.
Fleetfoot
not rated yet Jan 10, 2012
Anyway there are antiprotons trapped in the inner Van Allen belts.

The quantity is completely negligible in comparison to the mass of the Solar System and that is typical. Cosmic rays produce small quantities but it is not a significant fraction of the mass of the universe in terms of gravitational effects.
Not in our neighborhood anyway. Actually I'd say there is nearly an identical amount of antimatter and matter in the U.


There is no significant amount this side of the CMBR which means virtually nonw within a sphere of 45 billion light years radius from our location.

It's out there where the energy density of spacetime is maybe 1/3 to 1/2 the density in our neighborhood.


The variation in the CMBR which you see in the maps is a few parts per million. That means the energy density doesn't vary by much more than that anywhere within 45 billion light years of here. Your speculation doesn't match reality in the slightest.
Fleetfoot
not rated yet Jan 10, 2012
The CMBR works the same way, everyone in the universe can see light that has been travelling for no more than the age of the universe no matter where they are.
It's AWT model and it implies, Universe can be infinite.


I understood Aether theory didn't have a model, what is it's replacement for the Friedmann Equation?

Big Bang cosmology says instead, we cannot see farther, because of dark ages period of Universe.


The hydrogen absorbtion lines, mostly Lyman-alpha and beta, from the neutral gas during the dark ages produce the Gunn-Peterson trough:

http://en.wikiped...n_trough

We can still see through the universe at other wavelengths.

In this model you cannot travel along Universe into infinite distance.


In the big bang model, the universe can be either finite or infinite. We can't say which applies as yet (and may never be able to), but certainly it is much bigger than the region we can observe.
Callippo
1 / 5 (2) Jan 10, 2012
I understood Aether theory didn't have a model, what is it's replacement for the Friedmann Equation?
Friedmann equation is OK, it describes the expansion of Universe as well, as the Ptolemy's epicycles described the motion of planets on the sky. The only problem is, this motion is only apparent so it doesn't fit some observations.
The hydrogen absorbtion lines, mostly Lyman-alpha and beta, from the neutral gas during the dark ages produce the Gunn-Peterson trough..
What does it imply? The same effect could be observed with dense aether model, which leads to the red shift too. In quantitative parameters Big Bang cosmology works well, it just doesn't fit qualitative logics.
Callippo
1 / 5 (2) Jan 10, 2012
For example Einstein expansion paradox: space expands globally although it nowhere expands locally. http://www.scienc...ox-85942 But we have even deeper problems here. For example, For example, both Andromeda, both Milky Way galaxies are nearly 14 billion years old.
http://en.wikiped..._Way#Age
http://wiki.answe...a_galaxy

If the Universe emerged from singularity, then these galaxies should be nearly as distant, as the oldest galaxies inside of Hubble deep field. Which they indeed aren't and they even moving toward each other, so they're expected to collide in next few billions of years. One must be very strong supporter in Lambda-CDM/Big Bang model for to believe such a situation would be possible in it.
Callippo
1 / 5 (2) Jan 10, 2012
Just a few links: the Top 30 Problems with the Big Bang http://www.metare...p-30.asp
Questioning the Big Bang http://arxivblog.com/?p=335
Evidence Against the Expanding Universe Hypothesis http://www.etheri...ift.html
Fleetfoot
not rated yet Jan 10, 2012
I understood Aether theory didn't have a model, what is it's replacement for the Friedmann Equation?
Friedmann equation is OK, it describes the expansion of Universe ...


Exactly, as you say it deescribes the expansion of the universe, so if you don't have a big bang model, the question remains, what is your aether-based alternative?

The hydrogen absorbtion lines, mostly Lyman-alpha and beta, from the neutral gas during the dark ages produce the Gunn-Peterson trough.
What does it imply?


It means that a significant part of the hydrogen was neutral before a redshift of roughly z=6 after which it was almost entirely ionised. The first stars switching on just prior to that is the conventional explanation of course.

The same effect could be observed with dense aether model,


Go ahead then, explain your alternative.
Fleetfoot
not rated yet Jan 10, 2012
For example Einstein expansion paradox: space expands globally although it nowhere expands locally.

http://www.scienc...ox-85942


The article is wrong. In fact I did some work on the Pioneer anomaly and just out of curiosity considered the effect of expansion. The sign was wrong of course, it would produce a redshift instead of the observed blue, but the effect is only about an order of magnitude less than the "anomaly" so could be measured locally with a carefully designed mission of the type that Turyshev was suggesting.
Fleetfoot
not rated yet Jan 10, 2012
But we have even deeper problems here. For example, For example, both Andromeda, both Milky Way galaxies are nearly 14 billion years old.
http://en.wikiped..._Way#Age
http://wiki.answe...a_galaxy


Why are you misquoting? The first says the best fit is 12.6 for the Milky Way and the second 13.2 for Andromeda, perfectly normal values. They give one star as 14.0 but with an uncertainty of 2.4.

If the Universe emerged from singularity, then these galaxies should be nearly as distant, as the oldest galaxies inside of Hubble deep field.


Where did you get that nonsense?

Which they indeed aren't and they even moving toward each other, so they're expected to collide in next few billions of years.


So? Most galaxies everywhere are probably around 10 to 12 billion years old, they all started forming around the same time because conditions were the same everywhere. You seem to have a bizarre understanding of the model.
Fleetfoot
not rated yet Jan 10, 2012
Just a few links: the Top 30 Problems with the Big Bang
http://www.metare...p-30.asp
http://arxivblog.com/?p=335


Oh dear. Q2 from your first link:

"The microwave 'background' makes more sense as the limiting temperature of space heated by starlight than as the remnant of a fireball."

Wrong. The CMBR is a nearly perfect fit to a black body while a distributed source would give a near flat (or exponentially decaying) tail, the integral of a black body over here to infinity.

From your second link:

"The main problem with the Big Bang theory is that the cosmic background radiation does not have the characteristics youd expect ... the radiation curve has the distinct whiff of a black body about it, ... Most theorist do not imagine the Big Bang like this."

ROFL, the source was hydrogen/helium plasma at 2790K and a redshift of 1090, a black body is exactly what we expect.
Seeker2
1 / 5 (2) Jan 10, 2012
It's out there where the energy density of spacetime is maybe 1/3 to 1/2 the density in our neighborhood.
The variation in the CMBR which you see in the maps is a few parts per million. That means the energy density doesn't vary by much more than that anywhere within 45 billion light years of here. Your speculation doesn't match reality in the slightest.
I think that variation was on the surface of last scattering. I'm talking about the expansion of this surface itself, not any variation on the surface.
Seeker2
1 / 5 (2) Jan 10, 2012
But gravitation is caused by a difference in energy density.
No, it is caused by the energy density itself, not a difference.
No difference, no curvature, no gravity.

The energy density of antimatter is less than that of matter as I see it
You just agreed that "antimatter is identical to matter in energy content" so put each in a 1 cubic metre box and the energy density is the same too, trivially. For example, whether you put an electron or a positron in a 1m^3 box, the energy density is 511kEv / m^3
True, but I claim they don't come in same size boxes. Remember when I was talking about Peter and Paul they both have the same energy but quantum fluctuations caused a difference in volume between them (during pair production) with the total volume remaining the same, Peter getting the short end of the stick, or less volume. Same energy but different energy/unit volume.
Callippo
1 / 5 (2) Jan 10, 2012
Most galaxies everywhere are probably around 10 to 12 billion years old
Just because of it it's a problem of Big Bang model. Because remote galaxies are as mature as the Milky Way. They should be all younger in early stages of their formation. http://www.spacer...id=14524
Seeker2
1 / 5 (2) Jan 10, 2012
He will have to move into a neighborhood with lower energy density and Peter will get promoted to the higher density neighborhoods (like a black hole, the poor sucker).
No, the nearest low-density region is Paul so they would just revert to the original configuration, winking back out of existence as QM says.
Paul is a high density region. They will wink out of existence if there isn't enough energy in the quantum fluctuations to move them apart and allow spacetime to intervene and mediate the force of gravitational interaction. Intervening spacetime pushs Peter away and Paul pushs away on intervening spacetime so they go their separate ways and Peter and Paul become real particles. Now Peter is evicted from the neighborhood and must relocate to a lower density region. Paul of course moves along to higher and higher density regions until he gets his comeuppance in a black hole.
Seeker2
1 / 5 (2) Jan 10, 2012
BTW the excess energy between the quantum fluctuations and the energy required to produce the real particle pair is generally radiated away. Quantum fluctuations come in random sizes, as determined by the uncertainty principle. Sorry if I'm preaching to the choir.
Seeker2
1 / 5 (2) Jan 10, 2012
cont...
so now Peter occupies a volume of 1 and Paul a volume of 3. Same total energy (2E), same total volume (4), just a bit of energy density redistribution you might say. So now Peter has an energy density of E/1 (E) and Paul E/3. Voila. Paul gets the short end of the stick.
Fine but Peter might be a proton or anti-proton while Paul is the electron or positron, it still wouldn't differentiate matter from antimatter, only families of particles.
Whatever "it" is, Peter and Paul are twins, like matter/antimatter pairs - electrons/positrons or protons/anti-protons.
Seeker2
1 / 5 (2) Jan 10, 2012
as I see it each element of spacetime has a nominal energy (call it E) and a nominal energy density, but quantum fluctuations move the borders around between adjacent elements. You can get off at this STOP if you never heard of quantized spacetime.
I have but I think the Integral observations last year make it very unlikely.
These guys think spacetime or those grainy things should have a preferred direction in spacetime in order to affect GRB polarizations. Maybe I should get off at this STOP.
Seeker2
1 / 5 (2) Jan 10, 2012
I was only trying to find the expansion rate for whatever might be out there at 14mpc which should have been 14gpc as you noted.
OK, but why not calculate 140 GPC or 1400 GPC, it's just an arbitrary number. Just because that material happened to emit some light a long time ago which we can see now doesn't make it special other than for us.
Just out of curiosity, might that material still be around even though it's probably finished emitting?

Seeker2
1 / 5 (2) Jan 11, 2012
Hence quantum fluctuations are fluctuaions of energy density. If these fluctuations form one of the configurations allowed by QM or string theory or whatever they become locked in by gluons (think of them as elements of a template) to form a particle-antiparticle pair.
Hey Fleetfoot you may have missed one here. Electrons and positrons are not quark matter. There must be some other binding mechanism here. Maybe Dirac figured that one out.
Seeker2
1 / 5 (2) Jan 11, 2012
No, what it means is that the contribution from vacuum energy stays the same over time, hence it is a "Cosmological Constant". That doesn't mean it produces no effect, it produces a constant effect.
Einstein would like that. However it now appears we have an accelerating expansion, which requires energy. I assume that energy comes from the vacuum energy, unless there is some infinite source of energy out there. So the cosmological constant depends (decreases I suppose) with time. Unfortunate. Another one of those inconvenient truths.
Seeker2
1 / 5 (2) Jan 11, 2012
the energy in each region doesn't change, only the size, so put a box round both of them and it contains the same total energy as the empty box. Either that or I misunderstood your explanation.
Must be a bad explanation. Try this: Initially the empty box contains no energy. Now attach a divider so we have two compartments. No energy. Now push the divider from the inside so it stretches. The force of the push times the distance stretched does work resulting in one compressed compartment and one stretched compartment. The compartments now share energy, namely the work performed by the pusher (a quantum fluctuation). Now lock that divider in place with a gluon and an antigluon and you have two compartments with equal stored energy. Actually I've never heard of a gluon for positrons and electrons, but the same general idea holds.
Fleetfoot
not rated yet Jan 11, 2012
The variation in the CMBR which you see in the maps is a few parts per million. That means the energy density doesn't vary by much more than that anywhere within 45 billion light years of here. Your speculation doesn't match reality in the slightest.
I think that variation was on the surface of last scattering. I'm talking about the expansion of this surface itself, not any variation on the surface.


Right but that variation is representative of the variation of density on that spherical surface and an observer say 5 billion light years away would see the same which means it is also representative of the variation of the density throughout the volume bounded by that sphere.
Fleetfoot
not rated yet Jan 11, 2012
For example, whether you put an electron or a positron in a 1m^3 box, the energy density is 511kEv / m^3
True, but I claim they don't come in same size boxes.


I can calculate how much energy is is any sized box and for any given size, the densities are identical.

You miss the point though, in your description, the total energy is the same as a vacuum while we know real matter particles have non-zero mass. Your visualisation doesn't reflect that at all.

Remember when I was talking about Peter and Paul they both have the same energy but quantum fluctuations caused a difference in volume between them (during pair production) with the total volume remaining the same, Peter getting the short end of the stick, or less volume. Same energy but different energy/unit volume.


I remember that well, but a few posts farther on you now say that was wrong and the energy in each region is zero!
Fleetfoot
not rated yet Jan 11, 2012
Most galaxies everywhere are probably around 10 to 12 billion years old
Just because of it it's a problem of Big Bang model. Because remote galaxies are as mature as the Milky Way. They should be all younger in early stages of their formation.


ROFL, you forgot what this article is about even though you are responding to it.

Here's another:

http://www.physor...ies.html

The paper you quote is seven years old, the technology and our knowledge have moved on a very long way in that time.
Fleetfoot
not rated yet Jan 11, 2012
cont...
so now Peter occupies a volume of 1 and Paul a volume of 3. Same total energy (2E), same total volume (4), just a bit of energy density redistribution you might say. So now Peter has an energy density of E/1 (E) and Paul E/3. Voila. Paul gets the short end of the stick.
Fine but Peter might be a proton or anti-proton while Paul is the electron or positron, it still wouldn't differentiate matter from antimatter, only families of particles.
Whatever "it" is, Peter and Paul are twins, like matter/antimatter pairs - electrons/positrons or protons/anti-protons.


"It" means your idea. Note in the original post you quote here, you said each volume had an energy of 2E in contrast to your more recent post.

The bottom line though again is that you need 511keV of extra energy compared to the vacuum for an electron or a positron. If Peter and Paul and an electron and a positron then you need 511keV for each, a total of 1022keV, not zero.
Fleetfoot
not rated yet Jan 11, 2012
You can get off at this STOP if you never heard of quantized spacetime.
I have but I think the Integral observations last year make it very unlikely.
These guys think spacetime or those grainy things should have a preferred direction in spacetime in order to affect GRB polarizations. Maybe I should get off at this STOP.


There might still be a graininess but according to a professional in the field, after the Integral result was announced, there was the sound of many papers on string theory being shredded. To put it in context, the maximum grain size is probably contrained to be 13 orders of magnitude less than the Planck size.

Anyway, the way you are thinking about it doesn't work as I mentioned earlier. You might be interested in this though:

http://www.newsci...ime.html
Fleetfoot
not rated yet Jan 11, 2012
I was only trying to find the expansion rate for whatever might be out there at 14mpc which should have been 14gpc as you noted.
OK, but why not calculate 140 GPC or 1400 GPC, it's just an arbitrary number. Just because that material happened to emit some light a long time ago which we can see now doesn't make it special other than for us.
Just out of curiosity, might that material still be around even though it's probably finished emitting?


Sure, and it is no doubt still emitting, it'll just be a long time until that light gets here (if ever).

The Andromeda Galaxy is 3 million light years away so we see it as it was 3 million years ago but of course it is still there and still shining. The same is true of the matter which emitted the CMBR but it has now become galaxies and they are about 45 billion light years away. Scientists there will have a view little different from ours.
Fleetfoot
not rated yet Jan 11, 2012
Hey Fleetfoot you may have missed one here. Electrons and positrons are not quark matter. There must be some other binding mechanism here. Maybe Dirac figured that one out.


I didn't miss it, they are fundamental particles so have no internal parts needing to be bound together :-)
Fleetfoot
not rated yet Jan 11, 2012
Must be a bad explanation. Try this: Initially the empty box contains no energy.


That's different, they had 2E last time ;-)

Now attach a divider so we have two compartments. No energy. Now push the divider from the inside so it stretches. The force of the push times the distance stretched does work resulting in one compressed compartment and one stretched compartment. The compartments now share energy ..


No, the mechanical distortion of the divder holds the energy, not the empty spaces.

Actually I've never heard of a gluon for positrons and electrons, ...


That's because they aren't made from a group of quarks :-)

http://en.wikiped...particle
Fleetfoot
not rated yet Jan 11, 2012
No, what it means is that the contribution from vacuum energy stays the same over time, hence it is a "Cosmological Constant".
Einstein would like that.


He called it his "biggest blunder" but ironically the latest measurements of expansion suggest it is a perfect match for the acceleration.

However it now appears we have an accelerating expansion, which requires energy. I assume that energy comes from the vacuum energy, unless there is some infinite source of energy out there. So the cosmological constant depends (decreases I suppose) with time. Unfortunate. Another one of those inconvenient truths.


You are half right. It looks very likely that it is vacuum energy (as tested in the lab by the Casimir Effect) but because it acts like a negative pressure and force times distance is work done, that negative work cancels the additional kinetic energy of the matter so overall it conserves energy.
Seeker2
1 / 5 (2) Jan 13, 2012
Reverse the arrow of time and you have two electrons sitting side by side and they attract.
It seems to me attraction/repulsion are instantaneous - they don't depend on time passage.

Seeker2
1 / 5 (2) Jan 14, 2012
negative work cancels the additional kinetic energy of the matter so overall it conserves energy
Adding kinetic energy to matter requires positive work. I believe this is what happens during accelerated expansion.
Fleetfoot
not rated yet Jan 14, 2012
Reverse the arrow of time and you have two electrons sitting side by side and they attract.
It seems to me attraction/repulsion are instantaneous - they don't depend on time passage.


Throw an object in the air and it first rises, then stops, then falls back to Earth. If you plot a graph, the curve is quadratic. Reverse the time axis and the curve is the same shape, the object still accelerates towards Earth so gravity is still attractive. The same argument applies to the repulsion of two electrons.
Fleetfoot
not rated yet Jan 14, 2012
negative work cancels the additional kinetic energy of the matter so overall it conserves energy
Adding kinetic energy to matter requires positive work. I believe this is what happens during accelerated expansion.


That is part of it but gravity results from the "stress-energy tensor" which includes pressure as well as energy. The negative pressure part does negative work so overall the result is that no energy is needed if the effect is as given by Einstein's Cosmological Constant" (CC). If the effect varies with time (called "quintessence") then that may not be true.

As I said some time ago, the equation of state for the CC is w = -1 and the current best measurement is -0.980 give or take 0.053 so it's looking very much as though a CC is right.

http://en.wikiped...d_models
Seeker2
1 / 5 (2) Jan 14, 2012
Throw an object in the air and it first rises, then stops, then falls back to Earth. If you plot a graph, the curve is quadratic. Reverse the time axis and the curve is the same shape, the object still accelerates towards Earth so gravity is still attractive. The same argument applies to the repulsion of two electrons.
Yes gravity is attractive in forward and backwards time. Also anti-gravity is repulsive in forward and backwards time. However anti-gravity is experienced by anti-matter in forward and reverse times for reasons I discussed somewhere about pair creation. That was an epic battle which just seems to go on and on.
Seeker2
1 / 5 (2) Jan 14, 2012
gravity results from the "stress-energy tensor" which includes pressure as well as energy. The negative pressure part does negative work so overall the result is that no energy is needed if the effect is as given by Einstein's Cosmological Constant" (CC). If the effect varies with time (called "quintessence") then that may not be true.
Quintessence is what? Check out http://en.wikiped...physics) and then we can have a more meaningful discussion.

Seeker2
1 / 5 (2) Jan 14, 2012
Must be a bad explanation. Try this: Initially the empty box contains no energy.
That's different, they had 2E last time
Bad me. After the quantum fluctuation they still have the same energy, only different boundary position and volumes, resulting in different energy densities. Keeping me honest. I was thinking it took energy to move the boundary, but apparently it's only a random fluctuation. Now you have me thinking do those random fluctuations require energy? Apparently not. If fluctuations require energy then e/m waves would not propagate for billions of years.

force times distance is work done, that negative work...
Work done is certainly energy lost by the worker but gained by the visible U.
Seeker2
1 / 5 (2) Jan 14, 2012
gravity results from the "stress-energy tensor" which includes pressure as well as energy. The negative pressure part does negative work so overall the result is that no energy is needed if the effect is as given by Einstein's Cosmological Constant" (CC). If the effect varies with time (called "quintessence") then that may not be true.
Quintessence is what? Check out http://en.wikiped...physics) and then we can have a more meaningful discussion.
I see what you meant now. The time variation is an effect of quintessence, not quintessence itself.

Seeker2
1 / 5 (2) Jan 14, 2012
gravity results from the "stress-energy tensor"
Speaking of which I would like to expound on measuring the speed of gravity, as I think pair production is the only way of measuring this speed. Once the pair become real particles the antimatter floats away, but not matter. Its discontinuity in energy density spreads spherically thoughout spacetime, just like a light wave, or to be precise more like the amplitude of a light wave since the graviton has no periodicity. As the graviton or gravitational field spreads throughout spacetime it comes into contact with other gravitational fields and we can say they come into gravitational communication. Now as long as particles don't accelerate their field travels right along with them and their communication becomes instantaneous. Under acceleration however their fields will be updated (at the speed of light).
Seeker2
1 / 5 (2) Jan 14, 2012
con't...
The trick is during inflation the distance from particles was very small so all matter created during inflation almost instantly came into gravitational communication with each other. And they remain in instantaneous communication unless they are accelerated. Point being if we expect to find gravitational waves from distant objects which we can see these objects and their gravitational fields have long since departed their positions where we now see them. But we can pick up gravitational waves from objects that we are now in communication with and we will know their presence long before we can see them. An amazing new possibility for astronomy - know the universe as it is now, not billions of years in the past.
Seeker2
1 / 5 (2) Jan 14, 2012
con't...
As for the antimatter floating away - it propagates an anti-gravitational field. These neutralize normal matter gravitational fields so matter doesn't interact with antimatter as long as there are intervening elements of spacetime between them. Matter pulls on elements of spacetime and antimatter pushes on elements of spacetime, and without this intervening spacetime the particle-antiparticle pair annihilates. So much for quantum gravity.
Fleetfoot
1 / 5 (1) Jan 15, 2012
However anti-gravity is experienced by anti-matter in forward and reverse times for reasons I discussed somewhere about pair creation. That was an epic battle which just seems to go on and on.


We covered this before, anti-matter still provides positive energy in accelerator collisions therefore it creates the same positive curvature as normal matter, it is attractive.
Fleetfoot
not rated yet Jan 15, 2012
gravity results from the "stress-energy tensor" which includes pressure as well as energy. The negative pressure part does negative work so overall the result is that no energy is needed if the effect is as given by Einstein's Cosmological Constant" (CC). If the effect varies with time (called "quintessence") then that may not be true.
Quintessence is what? Check out http://en.wikiped...physics) and then we can have a more meaningful discussion.
I see what you meant now. The time variation is an effect of quintessence, not quintessence itself.


Yes, a simple example would be if quintessence was substance, its density would fall with time and so would its effect.
Fleetfoot
not rated yet Jan 15, 2012
gravity results from the "stress-energy tensor"
Speaking of which I would like to expound on measuring the speed of gravity, as I think pair production is the only way of measuring this speed. Once the pair become real particles the antimatter floats away, but not matter.


If the pair is an electron/positron for example, they wouldn't "float away", their charges mean they are strongly attracted.

This might help:

http://en.wikiped...oduction

"These pairs exist for an extremely short time, and mutually annihilate in short order. In some cases, however, it is possible to boost the pair apart using external energy so that they avoid annihilation and become real particles."

The pair themselves have only energy "borrowed" from the vacuum and cannot exist with momentum and duration more than that given by the uncertainty principle

http://en.wikiped...rinciple
Fleetfoot
5 / 5 (1) Jan 15, 2012


The pair themselves have only energy "borrowed" from the vacuum and cannot exist with momentum and duration more than that given by the uncertainty principle.


Sorry, that should have read ".. exist with energy and duration .."
Seeker2
1 / 5 (2) Jan 16, 2012
anti-matter still provides positive energy in accelerator collisions therefore it creates the same positive curvature as normal matter, it is attractive.
Positive energy does not mean positive curvature unless its energy density is greater than that of spacetime.
Seeker2
1 / 5 (2) Jan 16, 2012
If the pair is an electron/positron for example, they wouldn't "float away", their charges mean they are strongly attracted.
They have to have enough energy to overcome their attraction if they become real particles.

Seeker2
1 / 5 (2) Jan 16, 2012
if quintessence was substance, its density would fall with time and so would its effect.
I think the energy density of any substance remains constant until it decays or evaporates because as I understand gravitationally bound matter doesn't expand. Maybe they contract inside a black hole but they probably get ripped apart first. As for quintessence I was thinking it was like the dark force, the force of dark energy causing expansion (plus probably inflation and the creation of matter/antimatter).
Seeker2
1 / 5 (2) Jan 16, 2012
We might do a little conjecture about a QM scenario for pair production here. Elements of spacetime would begin to pair off with say compressed elements (matter) in an inner shell of spacetime elements and antimatter in an outer shell. As long as the shells are configured symmetrically there are no net force fields - spacetime in the outer world isn't effected in any way. If there is enough energy to force the concentric shells to separate then their fields no longer cancel and as they go their separate ways the fields become stronger and stronger. So the required force of separation increases as the pair separates. And if the force is sufficient the pair separates and become real particles. Something for the QM guys to kick around maybe.
Seeker2
1 / 5 (2) Jan 16, 2012
cont...
Note the idea of an outer shell being say anti-matter and the inner shell matter would be consistent with the idea of anti-matter occuping more volume than matter and thus having less energy density.
Seeker2
1 / 5 (2) Jan 16, 2012
You can get off at this STOP if you never heard of quantized spacetime.
I have but I think the Integral observations last year make it very unlikely.
These guys think spacetime or those grainy things should have a preferred direction in spacetime in order to affect GRB polarizations. Maybe I should get off at this STOP.


There might still be a graininess but according to a professional in the field, after the Integral result was announced, there was the sound of many papers on string theory being shredded. To put it in context, the maximum grain size is probably contrained to be 13 orders of magnitude less than the Planck size.

Anyway, the way you are thinking about it doesn't work as I mentioned earlier.
Maybe I should think like this: e/m waves are propagated on the surface of the grains. These surfaces normally vibrate as white noise with frequencies up to those of GRBs. e/m waves harness that energy and make them into coherent waves.
Fleetfoot
not rated yet Jan 17, 2012
anti-matter still provides positive energy in accelerator collisions therefore it creates the same positive curvature as normal matter, it is attractive.
Positive energy does not mean positive curvature unless its energy density is greater than that of spacetime.


Positive mean density for the matter in space means positive curvature regardless. If the vacuum also has a mean density then that contributes too. In GR, all forms of energy and pressure (and the cosmological constant) contribute so it is possible to get a flat universe even with positive matter and radiation densities. A good analogy is the skin of an orange, galaxies create dimples but they don't define the overall shape.
Fleetfoot
not rated yet Jan 17, 2012
If the pair is an electron/positron for example, they wouldn't "float away", their charges mean they are strongly attracted.
They have to have enough energy to overcome their attraction if they become real particles.


If they can get energy from some other source, then there is usually enough to separate them, but you can't say the amtimatter "drifts", both particles must move off with equal and opposite velocities to conserve momentum.
Fleetfoot
not rated yet Jan 17, 2012
if quintessence was substance, its density would fall with time and so would its effect.
I think the energy density of any substance remains constant until it decays or evaporates because as I understand gravitationally bound matter doesn't expand.


That seems to make no sense. Put your finger over the end of a bicycle pump. Push the handle down half way and you double the density of the air in the cylinder. Since e=mc^2, you have also double the energy density, it certainly isn't constant and I can't see what that has to to do with gravitationally bound groups of objects.
Seeker2
1 / 5 (2) Jan 18, 2012
There might still be a graininess but according to a professional in the field, after the Integral result was announced, there was the sound of many papers on string theory being shredded
Hold that shredder. Check out http://www.physor...ime.html
Seeker2
1 / 5 (2) Jan 18, 2012
gravitationally bound matter doesn't expand
I can't see what that has to to do with gravitationally bound groups of objects.
Gravity is much stronger than the force of spatial expansion (the 5th force or quintessence)
Fleetfoot
not rated yet Jan 18, 2012
There might still be a graininess but according to a professional in the field, after the Integral result was announced, there was the sound of many papers on string theory being shredded
Hold that shredder. Check out http://www.physor...ime.html


If it is an even tighter limit then there will be more fodder for the shredders :-)

I haven't had a chance to read the paper yet and the limits are in different units so I can't say if this cites and supersedes the Integral result.
Fleetfoot
not rated yet Jan 18, 2012
I think the energy density of any substance remains constant until it decays or evaporates because as I understand gravitationally bound matter doesn't expand

That seems to make no sense. Put your finger over the end of a bicycle pump. Push the handle down half way and you double the density of the air in the cylinder. Since e=mc^2, you have also double the energy density, it certainly isn't constant and I can't see what that has to to do with gravitationally bound groups of objects.
Gravity is much stronger than the force of spatial expansion (the 5th force or quintessence)


I mean I can't see why you think gravity has any relevance to the energy density of a substance, for example that of air in a bicycle pump.

We can talk about short range gravity versus the cosmological constant separately but you seem hung up on densities so I'm trying to understand what you are thinking in that regard.
Seeker2
1 / 5 (2) Jan 18, 2012
I can't see why you think gravity has any relevance to the energy density of a substance, for example that of air in a bicycle pump.
Thanks for your interest. In a bicycle pump you have to suck in air (pull up on the handle) and then compress the air (push down on the handle. Think of the compressed air as being matter put into your tire. To get that matter you have to suck in air. Think of that suction as being gravity. Actually as you pump more air you have to suck in more air, so gravity is directly related to the amount of matter created. So you have basically reconfigured the atmosphere. But that reconfiguration isn't going to last forever because it's a lower state of entropy than before you did the pumping. IMO all particles/forces are basically a result of spacetime being reconfigured and attempting to return to its original state of higher entropy.
Seeker2
1 / 5 (2) Jan 19, 2012
IMO all particles/forces are basically a result of spacetime being reconfigured and attempting to return to its original state of higher entropy.
Ergo spacetime has memory. Never thought about that.
Fleetfoot
not rated yet Jan 21, 2012
In a bicycle pump you have to suck in air (pull up on the handle) and then compress the air (push down on the handle. Think of the compressed air as being matter put into your tire. To get that matter you have to suck in air. Think of that suction as being gravity.


That doesn't really work. First, gravity exists within the universe, it's more like the Van der Waals forces between the air molecules in the pump. Second there is no outside from which the contents can be drawn.

.. that reconfiguration isn't going to last forever because it's a lower state of entropy than before you did the pumping.


Good point, the question of entropy in cosmology is quite complex and still a puzzle.

Going back to the previous posts though, there is no link between the fact that the Milky Way galaxy is a gravitationally bound collection of stars doesn't affect the density of the air in my bicycle tyres so I still think you are conflating unrelated concepts.
Seeker2
1 / 5 (2) Jan 21, 2012
That doesn't really work. First, gravity exists within the universe,
Yes, air exists in the atmosphere.

it's more like the Van der Waals forces between the air molecules in the pump.
Compressed air is intended to represent matter, which I model as some form of compressed spacetime. Else where does matter come from? It's only one possible configuration of spacetime.
Second there is no outside from which the contents can be drawn.
I see spacetime as being outside matter similar to atmosphere outside the airpump. Spacetime and matter are made of the same stuff, just like air in the pump and the atmosphere are made of the same stuff.

Callippo
1 / 5 (1) Jan 21, 2012
Spacetime and matter are made of the same stuff, just like air in the pump and the atmosphere are made in the same stuff.
This is not very illustrative, as the material of pump and atmosphere differ in their qualities. Why not to simply compare the particles of matter inside of vacuum to the droplets of water inside of water vapor?
Seeker2
1 / 5 (2) Jan 21, 2012
Good point, the question of entropy in cosmology is quite complex and still a puzzle.

Going back to the previous posts though, there is no link between the fact that the Milky Way galaxy is a gravitationally bound collection of stars doesn't affect the density of the air in my bicycle tyres so I still think you are conflating unrelated concepts.

Sorry I stole your stuff. Can't seem to get it into high gear tonight. Must be all that snow shoveling. I agree your idea about galaxies and air in the tires seems to be a bit quixotic. Wow I never used that word before. Wonder how it will work.
Seeker2
1 / 5 (2) Jan 21, 2012
Spacetime and matter are made of the same stuff, just like air in the pump and the atmosphere are made in the same stuff.
This is not very illustrative, as the material of pump and atmosphere differ in their qualities.
Forget about the material of pump and concentrate on what's inside the pump.

Why not to simply compare the particles of matter inside of vacuum to the droplets of water inside of water vapor?
Sounds too much like AWT to me. Don't take it personally though.
Callippo
1 / 5 (1) Jan 21, 2012
Sounds too much like AWT to me. Don't take it personally though.
You see, if laymans like you refute the best analogies just because they sound too aetherically - what else we could expect from mainstream physicists? Their maneuvering space is quite limited here. Whole world know, I'm right - you know it and I know you know it too - but everyone will pretend, such explanation doesn't exist - or the whole game will be over. This is how every hypocrisy ends.

http://www.aether...memo.gif
Seeker2
1 / 5 (2) Jan 21, 2012
If I know it then don't bother telling me about it.
Callippo
1 / 5 (2) Jan 22, 2012
It's hyperdimensional information. I'm telling you just for you to know, I know what you know.
Seeker2
1 / 5 (2) Jan 22, 2012
a gravitationally bound collection of stars doesn't affect the density of the air in my bicycle tyres so I still think you are conflating unrelated concepts.
Sounds sort of like you're trying to set up a strawman here. But I did miss an important point. Air is a form of matter ergo has structure and gravity. Your tire actually weighs more after pumping it up.
Fleetfoot
not rated yet Jan 22, 2012
Compressed air is intended to represent matter, which I model as some form of compressed spacetime. Else where does matter come from? It's only one possible configuration of spacetime.


"Matter" is one classification of energy.

Second there is no outside from which the contents can be drawn.
I see spacetime as being outside matter similar to atmosphere outside the airpump. Spacetime and matter are made of the same stuff, just like air in the pump and the atmosphere are made of the same stuff.


OK, I had read your post to mean that the contents of the universe had been pumped in from somewhere else, my mistake.

If that's how you look at it, there isn't a problem. Whether particles are compressed spacetime or not, they have energy and momentum and that's all we need to consider. The term energy density is the amount of energy per unit volume averaged over any arbitrary region of space. It includes all forms of energy so the nature of the particles is irrelevant.
Fleetfoot
not rated yet Jan 22, 2012
Spacetime and matter are made of the same stuff, just like air in the pump and the atmosphere are made in the same stuff.
This is not very illustrative, as the material of pump and atmosphere differ in their qualities. Why not to simply compare the particles of matter inside of vacuum to the droplets of water inside of water vapor?


Yes, that would have been clearer. You then have one value for the density of the vapour which should be the same everywher. The water density in the form of drops however can vary from region to region as they may clump together or forms voids between clumps due to their random motion.
Fleetfoot
not rated yet Jan 22, 2012
a gravitationally bound collection of stars doesn't affect the density of the air in my bicycle tyres so I still think you are conflating unrelated concepts.
Sounds sort of like you're trying to set up a strawman here.


No, just trying to remove the confusion over the meaning of "energy density", it was getting in the way of the dicussion.

But I did miss an important point. Air is a form of matter ergo has structure and gravity. Your tire actually weighs more after pumping it up.


True but I didn't think that was relevant for the analogy. Laying aside your model, pumping up the tyre also heats the gas:

E=mc^2

The mass is also greater when the compressed air is still hot and reduces as heat is lost through the walls of the tyre. It both weighs more and creates more gravity when hot. Not only that, the pressure itself also creates gravity. The source is the stress-energy tensor and the "stress" part is the pressure.
Callippo
1 / 5 (2) Jan 22, 2012
As usually in AWT, all these particular models are observational perspective dependent. For example in description of cosmology the so-called "block model" of universe works better. This model is oriented to dispersive mechanism of light spreading in vacuum and the existence of event horizons of Universe is the result of dispersion of energy inside of environment of roughly constant density. It means, the most distant areas of Universe behave like surface of singularity not because they're too dense (as Big Bang model implies), but simply because they're too distant, so they're dispersed like the scope of view inside of fog. The AWT itself it essentially orthogonal to all these particular views - it just predicts, at sufficiently distant / global perspective they all will converge together and they will become indistinguishable each other.
Fleetfoot
5 / 5 (1) Jan 22, 2012
The AWT itself it essentially orthogonal to all these particular views - it just predicts, at sufficiently distant / global perspective they all will converge together and they will become indistinguishable each other.


Where are the calculations showing that? I have seen many people make claims for their aether models but not one of them has ever actually had a theory when pushed, it has always been just talk and wishful thinking.
Callippo
1 / 5 (2) Jan 22, 2012
Where are the calculations showing that?
"Calculations" aren't miracle of heavens, which can prove whatever BS thinkable (although authors of many theories are pretending, they do so). So you cannot understand/derive calculations, if you don't understand/defined the underlying logic. It's like the solving the homework with equations, without understanding of its assignation. You should understand the model first at its physical level before starting to think about its mathematical formulation.

The underlying idea of AWT is, the Universe is random material stuff and the people are one of its fluctuations which interacts with the another ones through transverse and longitudinal waves in similar way, like the soliton at the water surface. Despite you're believing in this model or not, it's evident, too large or too small objects will appear for such fluctuation like the indeterministic noise. If you cannot realize it, then you cannot deduce anything from AWT, derive the less.
Callippo
1 / 5 (1) Jan 22, 2012
Yes, that would have been clearer. You then have one value for the density of the vapor which should be the same everywhere. The water density in the form of drops however can vary from region to region as they may clump together or forms voids between clumps due to their random motion.
Thanks - but the effectiveness of physical models doesn't depend on how well they can interpret the well known phenomena, but which testable predictions they can provide.
Seeker2
1 / 5 (2) Jan 22, 2012
the pressure itself also creates gravity. The source is the stress-energy tensor and the "stress" part is the pressure.
Good point. Thanks. Pressure you could say squeezes matter into a smaller volume, causing an increase in the differential energy density between spacetime outside the volume containing the matter and the volume containing the matter. Spacetime becomes more stressed, less entropy, more effect of the stress-energy tensor. So the stress in the stress-energy tensor is actually a differential energy density.
Seeker2
1 / 5 (2) Jan 22, 2012
Laying aside your model, pumping up the tyre also heats the gas:

E=mc^2
plus mv^2/2. Heat goes into kinetic energy as I understand it, not into the internal energy of the matter.
Fleetfoot
not rated yet Jan 22, 2012
Where are the calculations showing that?
"Calculations" aren't miracle of heavens, which can prove whatever BS thinkable ...


The underlying idea of AWT is ...

Thanks - but the effectiveness of physical models doesn't depend on how well they can interpret the well known phenomena, but which testable predictions they can provide.


Analogies are only useful for communication and discussion which and for that yours was better.

In science though a theory must make quantitative predictions and that is where the aether concept failed. The basic luminiferous aether was indistinguishable from SR in that it resulted in the same Lorentz Transforms but was entirely phenomenological and couldn't explain gravity. The claims you are making are completely baseless.

This is rather strange because I an arguing for gravitational substantivalism in another forum which is probably closer to an aether theory than anything you can offer.
Fleetfoot
not rated yet Jan 22, 2012
the pressure itself also creates gravity. The source is the stress-energy tensor and the "stress" part is the pressure.
Good point. Thanks. Pressure you could say squeezes matter into a smaller volume, causing an increase in the differential energy density between spacetime outside the volume containing the matter and the volume containing the matter. Spacetime becomes more stressed ...


No. The energy density of the spacetime (i.e. the vacuum energy) outside and inside is the same, only the matter is being compressed. This is where you are confusing the terms.

Pressure is force per unit area and force is rate of change of momentum. Flow of momentum is a surce of gravity and it is the change of momentum of the particles that generates the gravity. The spacetime has nothing to do with it.
Fleetfoot
not rated yet Jan 22, 2012
Laying aside your model, pumping up the tyre also heats the gas:

E=mc^2
plus mv^2/2. Heat goes into kinetic energy as I understand it, not into the internal energy of the matter.


Right, they are the microscopic and macroscopic views of the same thing. The masses of the particles don't change of course.
Seeker2
1 / 5 (2) Jan 22, 2012
only the matter is being compressed. This is where you are confusing the terms.
Matter requires spacetime. Matter and spacetime are not separate entities.
rawa1
1 / 5 (2) Jan 23, 2012
This is rather strange because I an arguing for gravitational substantivalism in another forum which is probably closer to an aether theory than anything you can offer.
I'm just saying, it's essentially OK to consider the gravity field as a density gradient of vacuum around massive bodies, but the opposite perspective is equally valid: the space-time is flat and the energy is dispersing and shielded around massive bodies, which produces the gravity. I don't know, what the "gravitational substantivalism" is supposed to be, but the shielding model of gravity enables to derive the gravitational law a way easier (compare the LeSage theory). IMO it's the similar duality, like the duality of relativity and quantum mechanics, just at the aether level. It just depends on the choice of reference frame, which model will be considered more relevant.
rawa1
1 / 5 (2) Jan 23, 2012
IMO the model of gravity field as the massive lens is working better for transverse waves of vacuum, like the light and the shielding model of gravity works better for longitudinal waves of vacuum. Both these models are equally correct at their corresponding range of energy density scale - but at its boundaries they should be both handled with caution due the mutual violations of both models. AWT is about flexibility in thinking and consideration of observational perspectives during promotion of particular models. We should always take on mind, what we are getting and losing with consideration of particular model. It's not religious model based on belief in some fixed configuration of Universe.
rawa1
1 / 5 (2) Jan 23, 2012
Please note, that the model of gravity field as a density profile of vacuum doesn't work too well, when the path of light becomes curved into itself, i.e. at the case of hyperdimensional behaviour of black holes. We cannot apply laws of simple Hamiltonian optics in such case. In such cases the dispersive model of space-time works better again due its intrinsic hyperdimensional nature.
Fleetfoot
not rated yet Jan 23, 2012
Matter requires spacetime. Matter and spacetime are not separate entities.


Time is what stops everything happening at once, space is what stops everything being in one place. Matter needs spacetime to keep it apart. Similarly, it is very difficult to define the metric of spacetime without having a sprinkling of matter in it which can be measured. They are distinct but interdependent so I wouldn't disagree with what you say above.

Where you are getting it wrong though is trying to use the difference in densities. Relative to the critical level needed for the universe, dark energy contributes 72%, dark matter 23% and visible stuff about 4%. The total is the sum of those parts, not the difference.
Fleetfoot
not rated yet Jan 23, 2012
I don't know, what the "gravitational substantivalism" is supposed to be, ..


This is probably the mostly widely referenced page on the concept and the "Hole Argument" against it:

http://plato.stan...holearg/

There is a much shorter blog post introduction here:

http://www.andrew...ism.html

... the shielding model of gravity enables to derive the gravitational law a way easier (compare the LeSage theory).


Le Sage's gravity was grossly flawed, it would produce drag on planets unless the particle speed was far higher than the speed of light, and the heating effect would vaporise a planet in a fraction of a second unless the speed was very low. The model could only approximately reproduce Newtonian gravity and we now know that is wrong anyway.

It just depends on the choice of reference frame, which model will be considered more relevant.


I'm afraid not, Le Sage was always unworkable.
Fleetfoot
not rated yet Jan 23, 2012
... the shielding model of gravity works better for longitudinal waves of vacuum. Both these models are equally correct ...


Newtonian gravity is only a good approximation for weak fields, Le Sage shares its limitations but also fails for reasons I gave before. GR has never been found to be wrong at any scale above QM. If you want an alternative, try TeVeS:

http://en.wikiped..._gravity

AWT is about flexibility in thinking ...


Actually, as far as I can gather, there is no such thing as "AWT", just a lot of talk about ideas but no maths that could be tested by making quantitative predictions so no "theory" in the scientific sense.
Seeker2
1 / 5 (2) Jan 23, 2012
Where you are getting it wrong though is trying to use the difference in densities. Relative to the critical level needed for the universe, dark energy contributes 72%, dark matter 23% and visible stuff about 4%. The total is the sum of those parts, not the difference.
You're only off by 100%. The total difference in densities is 0. Areas of higher density have to be matched with those of lower densities. Just one of those unfortunate laws of nature. Mixing apples and oranges might work great in some rhetoric classes but not in physics. It seems you also checked out the courses in setting up strawmen and obfuscation.
Callippo
1 / 5 (3) Jan 23, 2012
..Le Sage's gravity was grossly flawed, it would produce drag on planets unless the particle speed was far higher than the speed of light..
Well, let consider the speed of these particle is sufficiently high. I've no problem with superluminal speed of gravitational waves. But this model predicts even the behaviour of dark matter, so it should be handled with caution. Anyway, you have no better explanation of gravity and inverse square law, so we can leave it as it is, until you provide some alternative.
Fleetfoot
5 / 5 (1) Jan 24, 2012
..Le Sage's gravity was grossly flawed, it would produce drag on planets unless the particle speed was far higher than the speed of light..
Well, let consider the speed of these particle is sufficiently high.


The higher the speed, the greater the problem of heating.

I've no problem with superluminal speed of gravitational waves.


Gravitational waves travel at the speed of light in GR but wouldn't exist in Le Sage's gravity (same as Newton).

But this model predicts even the behaviour of dark matter


Le Sage's gravity is the same as Newton's, it was just an attempt to find a mechanism for his "action at a distance".

Anyway, you have no better explanation of gravity and inverse square law ..


Of course we have, General Relativity replaced Newtonian gravity almost a century ago. The inverse square law is wrong, you have to use tensors to get it right.
Fleetfoot
5 / 5 (1) Jan 24, 2012
Where you are getting it wrong though is trying to use the difference in densities. Relative to the critical level needed for the universe, dark energy contributes 72%, dark matter 23% and visible stuff about 4%. The total is the sum of those parts, not the difference.
You're only off by 100%. The total difference in densities is 0. ...


What I have said is all textbook stuff and complies with all the laws of physics. Your misunderstanding comes from your bizarre idea about "compressed spacetime".

Our best measurements say the universe seems to be flat which means the total energy should be zero (or very close to it). The gravitational potential is negative so you need positive energy from the contents to have a total of zero. The inventory I quoted is from this article:

http://www.univer...ventory/

It's worth reading the "technical note" at the bottom which explain why they are percentages.

Seeker2
1 / 5 (2) Jan 24, 2012
dark energy contributes 72%, dark matter 23% and visible stuff about 4%. The total is the sum of those parts, not the difference.
Our best measurements say the universe seems to be flat which means the total energy should be zero (or very close to it).
That's interesting. Assuming dark energy is positive the matter stuff must be negative. Something seems strange here. Certainly the total energy of the U is zero but apparently we're missing something. I've speculated about that elsewhere but it gets rather involved. The flat stuff refers to the overall configuration of spacetime. It's really a no-brainer. All the compressed spacetime (matter, dark matter) is balanced by the expanded spacetime (antimatter, antidarkmatter). So overall it's a wash.
Seeker2
1 / 5 (2) Jan 24, 2012
cont...
The difference refers to the reconfiguration of spacetime. This requires compression, expansion, twisting, or whatever else happens to change it. It might even mean severing elements of spacetime and trapping them in some otherwise empty volume. Anyway apparently the total volume of spacetime is conserved (ergo "flat").

Here's a theory: The existence of fields is because spacetime has memory. That memory makes it possible to set up vibrations or static fields. Your music instrument strings wouldn't vibrate unless they remembered where they were before you plucked the string. Actually mostly this is just theory until I find something more plausible either in the textbooks or in the imagination[;)
Seeker2
1 / 5 (2) Jan 24, 2012
I know what you know.
Wow. Now that's spooky.
Fleetfoot
not rated yet Jan 24, 2012
Our best measurements say the universe seems to be flat which means the total energy should be zero (or very close to it).
That's interesting. Assuming dark energy is positive the matter stuff must be negative. Something seems strange here. Certainly the total energy of the U is zero but apparently we're missing something.


What you are missing is that gravitational potential energy is negative:

http://en.wikiped...l_energy

All the stuff in the universe started close together so the potential was very negative. Making the gravitational potential might seem arbitrary because it is a gauge but consider the virial theorem:

http://en.wikiped..._theorem

A good example of its use is in globular clusters. If the total kinetic energy of the stars is E, the total gravitational potential energy is -2E and the system is bound because the total is less than zero. The same rule works for individual planets too.
Fleetfoot
not rated yet Jan 24, 2012
cont...

You might also like to check the Physics FAQ:

http://www.phys.n..._gr.html

In particular, note near the bottom:

"We will not delve into definitions of energy in general relativity such as the Hamiltonian (amusingly, the energy of a closed universe always works out to zero according to this definition), .."


A flat universe has exactly the critical density, one electron more and it is closed. As the article says, it is hard to prove the total energy is zero but it is asymptotically close to it.

Here's a theory: ...


Nah, that's only an idea. If you had a theory, you could write down its equations and show they match all current observations ;-)
Seeker2
1 / 5 (2) Jan 24, 2012
What you are missing is that gravitational potential energy is negative:

http://en.wikiped...l_energy
Very good. You're onto something. Gravitational potential energy balances the internal energy of matter. When matter is or was formed spacetime is or was compressed into the particle and stretched outside of the particle. This stretching force is what they call gravity. Plus dark matter may be higher density areas of intergalactive space balanced by lower density areas. So ok now all you have to account for is the positive energy of dark matter. You brag about your equations but you can't even add up all the components or even figure out what they should be.

All the stuff in the universe started close together
Note including spacetime.
Seeker2
1 / 5 (2) Jan 24, 2012
A good example of its use is in globular clusters. If the total kinetic energy of the stars is E, the total gravitational potential energy is -2E and the system is bound because the total is less than zero.
Interesting. If the negative potential energy of the gravitational field is balanced by the internal energy of the matter, as I (or is it we?) claim, then the kinetic energy of the cluster is one half its internal matter energy. Also since the gravitational potential energy of the cluster cancels the internal energy of its matter, the 4% figure must be for that of its kinetic energy. The 2E would then be the internal matter energy of the cluster. Aren't we smart.
Seeker2
1 / 5 (2) Jan 24, 2012
Maybe clusters. Sorry 'bout that.
Seeker2
1 / 5 (1) Jan 25, 2012
Here's a theory: ...

Nah, that's only an idea.

Uh-oh. Sounds like a guy I used to jaw with about gravity, I think it was.

I know what you know.

Wow. Now that makes 2 guys who know where I live. Double scary.
Fleetfoot
5 / 5 (1) Jan 25, 2012
What you are missing is that gravitational potential energy is negative:

http://en.wikiped...l_energy
Very good. You're onto something.


No credit to me, as I said, it's all basic textbook stuff.

Gravitational potential energy balances the internal energy of matter.
It balances all the forms of energy, see the detailed inventory I cited before.

This stretching force is what they call gravity.


No, gravity is what we call the effect of the resulting distortion of the geometry of spacetime.

So ok now all you have to account for is the positive energy of dark matter. You brag about your equations but you can't even add up all the components or even figure out what they should be.


Again, see the detailed inventory I have cited several times. It's a UniverseToday article with links to the original documents.
Fleetfoot
not rated yet Jan 25, 2012
A good example of its use is in globular clusters. If the total kinetic energy of the stars is E, the total gravitational potential energy is -2E and the system is bound because the total is less than zero.
Interesting. If the negative potential energy of the gravitational field is balanced by the internal energy of the matter, as I (or is it we?) claim, then the kinetic energy of the cluster is one half its internal matter energy.


I used that as an example explaining why gravitational potential energy is taken as negative. In that case, it only relates to the kinetic energy of the stars, not the E=mc^2 internal energy.

For the universe overall though, the total negative energy does balance the total positive energy. Here's the link again:

http://www.univer...ventory/
Seeker2
1 / 5 (1) Jan 25, 2012
the total negative energy does balance the total positive energy. Here's the link again:

http://www.univer...ventory/
I see nothing here to balance out the dark energy. Did I miss something?
Fleetfoot
not rated yet Jan 26, 2012
I see nothing here to balance out the dark energy. Did I miss something?


All you missed is that dark energy is on the same side of the balance as all the other contributions.

We know how much energy there needs to be overall to make the universe spatially flat. Of that amount, dark energy is 72%, dark matter is 23%, intergalactic plasma is 4% and all the rest constitute less than 1%. What suggests we are on the right track is that the total is 100% to within the accuracy of the measurements.
Seeker2
1 / 5 (1) Jan 26, 2012
I see nothing here to balance out the dark energy. Did I miss something?


All you missed is that dark energy is on the same side of the balance as all the other contributions.
So everything is on the same side of the balance? How could that be balanced?

Fleetfoot
not rated yet Jan 29, 2012
I see nothing here to balance out the dark energy. Did I miss something?


All you missed is that dark energy is on the same side of the balance as all the other contributions.
So everything is on the same side of the balance? How could that be balanced?



As I said before, it balances the overall negative gravitational potential energy AIUI. For a closed universe, the Hamiltonian is zero and the flat universe is asymptotically close to closed. Here's the FAQ article again:

http://math.ucr.e..._gr.html