Dark energy is real, say astronomers

Sep 12, 2012
A visual impression of the data used in the study. The relevant extra-galactic maps are represented as shells of increasing distance from Earth from left to right. The closest thing seen is our Milky Way galaxy, which is a potential source of noise for the analysis. After this are six shells containing maps of the millions of distant galaxies used in the study. These maps are produced using different telescopes in different wavelengths and are colour-coded to show denser clumps of galaxies as red and under-dense regions as blue. There are holes in the maps due to data quality cuts. The last, largest shell shows the temperature of the cosmic microwave background from the WMAP satellite (red is hot, blue is cold), which is the most distant image of the Universe seen, some 46 billion light-years away. The team have detected (at 99.996% significance) very small correlations between these foreground maps (on the left) and the cosmic microwave background (on the right). Image credits: Earth: NASA/BlueEarth; Milky Way: ESO/S. Brunier; CMB: NASA/WMAP. Click for a high resolution image.

(Phys.org)—Dark energy, a mysterious substance thought to be speeding up the expansion of the Universe is really there, according to a team of astronomers at the University of Portsmouth and LMU University Munich.

After a two-year study led by Tommaso Giannantonio and Robert Crittenden, the scientists conclude that the likelihood of its existence stands at 99.996 per cent. Their findings are published in the journal .

Professor Bob Nichol, a member of the Portsmouth team, said: " is one of the great scientific mysteries of our time, so it isn't surprising that so many researchers question its existence.

"But with our new work we're more confident than ever that this exotic component of the Universe is real – even if we still have no idea what it consists of."

Over a decade ago, astronomers observing the brightness of distant supernovae realised that the appeared to be accelerating. The acceleration is attributed to the repulsive force associated with dark energy now thought to make up 73 per cent of the content of the cosmos. The researchers who made this discovery received the Nobel Prize for Physics in 2011, but the existence of dark energy remains a topic of hot debate.

Many other techniques have been used to confirm the reality of dark energy but they are either indirect probes of the or susceptible to their own uncertainties. Clear evidence for dark energy comes from the Integrated Sachs Wolfe effect named after Rainer Sachs and Arthur Wolfe.

The Cosmic Microwave Background, the radiation of the residual heat of the Big Bang, is seen all over the sky. In 1967 Sachs and Wolfe proposed that light from this radiation would become slightly bluer as it passed through the gravitational fields of lumps of matter, an effect known as .

In 1996, Robert Crittenden and Neil Turok, now at the Perimeter Institute in Canada, took this idea to the next level, suggesting that astronomers could look for these small changes in the energy of the light, or photons, by comparing the temperature of the radiation with maps of galaxies in the local Universe.

In the absence of dark energy, or a large curvature in the Universe, there would be no correspondence between these two maps (the distant cosmic microwave background and relatively closer distribution of galaxies), but the existence of dark energy would lead to the strange, counter-intuitive effect where the cosmic microwave background photons would gain energy as they travelled through large lumps of mass.

The Integrated Sachs Wolfe effect was first detected in 2003 and was immediately seen as corroborative evidence for dark energy, featuring in the 'Discovery of the year' in Science magazine. But the signal is weak as the expected correlation between maps is small and so some scientists suggested it was caused by other sources such as the dust in our galaxy. Since the first Integrated Sachs Wolfe papers, several astronomers have questioned the original detections of the effect and thus called some of the strongest evidence yet for dark energy into question.

In the new paper, the product of nearly two years of work, the team have re-examined all the arguments against the Integrated Sachs Wolfe detection as well as improving the maps used in the original work. In their painstaking analysis, they conclude that there is a 99.996 per cent chance that dark energy is responsible for the hotter parts of the cosmic microwave background maps (or the same level of significance as the recent discovery of the Higgs boson).

"This work also tells us about possible modifications to Einstein's theory of General Relativity", notes Tommaso Giannantonio, lead author of the present study.

"The next generation of and galaxy surveys should provide the definitive measurement, either confirming general relativity, including dark energy, or even more intriguingly, demanding a completely new understanding of how gravity works."

Explore further: Quest for extraterrestrial life not over, experts say

More information: The new work appears in "The significance of the integrated Sachs-Wolfe effect revisited", T. Ginnantonio, R. Crittenden, R. Nichol, A. Ross, Monthly Notices of the Royal Astronomical Society, in press. A preprint of the paper is available from arxiv.org/abs/1209.2125

Related Stories

Dark energy -- 10 years on

Nov 30, 2007

Three quarters of our universe is made up of some weird, gravitationally repulsive substance that was only discovered ten years ago – dark energy. This month in Physics World, Eric Linder and Saul Perlmutter, both at the ...

Durham astronomers' doubts about the 'dark side'

Jun 14, 2010

(PhysOrg.com) -- New research by astronomers in the Physics Department at Durham University suggests that the conventional wisdom about the content of the Universe may be wrong. Graduate student Utane Sawangwit ...

Galaxy Evolution Explorer finds dark energy repulsive

May 20, 2011

(PhysOrg.com) -- A five-year survey of 200,000 galaxies, stretching back seven billion years in cosmic time, has led to one of the best independent confirmations that dark energy is driving our universe apart at a ...

Light from galaxy clusters confirms theory of relativity

Sep 28, 2011

All observations in astronomy are based on light emitted from stars and galaxies and, according to the general theory of relativity, the light will be affected by gravity. At the same time all interpretations ...

Recommended for you

Quest for extraterrestrial life not over, experts say

Apr 18, 2014

The discovery of an Earth-sized planet in the "habitable" zone of a distant star, though exciting, is still a long way from pointing to the existence of extraterrestrial life, experts said Friday. ...

Continents may be a key feature of Super-Earths

Apr 18, 2014

Huge Earth-like planets that have both continents and oceans may be better at harboring extraterrestrial life than those that are water-only worlds. A new study gives hope for the possibility that many super-Earth ...

Exoplanets soon to gleam in the eye of NESSI

Apr 18, 2014

(Phys.org) —The New Mexico Exoplanet Spectroscopic Survey Instrument (NESSI) will soon get its first "taste" of exoplanets, helping astronomers decipher their chemical composition. Exoplanets are planets ...

User comments : 144

Adjust slider to filter visible comments by rank

Display comments: newest first

kochevnik
1.3 / 5 (28) Sep 12, 2012
The logarithmic spiral structure of spiral galaxies precludes dark matter.
Anda
3.8 / 5 (10) Sep 12, 2012
Ok kochevnik whatever u say, and this applies to this article??? :(
kochevnik
1.3 / 5 (25) Sep 12, 2012
If dark matter is real why do logarithmic spiral galaxies do fine without it? Occam's razor
evolution3
not rated yet Sep 12, 2012
Maybe because the data suggests taht the universe expands accelerated?
AWaB
2.2 / 5 (21) Sep 12, 2012
We have observed an anomaly, i.e. the accelerating expansion of the universe. By saying dark energy over and over again, that won't make it any more right or wrong of a theory. What is dark energy? Until we know what it is, we don't know anything. This is a very poor attempt by these astronomers to prove anything. Slapping a statistical significance on it just makes it laughable.
Benni
1.2 / 5 (21) Sep 12, 2012
I'll make an attempt at some very complex math here. If "dark energy" makes up "73% of the content of the cosmos", this means 73% of all gravity in the universe finds its' source within this energy field.

Always curious too as to what wavelengths these investigators are talking about when they refer to "dark energy". All energy is composed of electro-magnetic lines of flux, it doesn't matter if you put "dark", "visible light", "infrared" or whatever other portion of the electro-magnetic spectrum in front of the word "energy".

For once I'd like to hear someone tell us what end of the EM spectrum they've been looking at to find "dark energy". We know it must be below the lowest range of frequency which are magnetic lines of flux & above the highest range of frequency which is gamma ray. Anybody posting here ever seen a credible paper or abstract for a paper such an investigation? And you AWT cranks, don't bother with your suggestions.......
Deathclock
4.1 / 5 (28) Sep 12, 2012
Almost all cosmologists/astronomers/physicists think it's real, almost all cranks that spend all their time commenting on an obscure science republishing site think it is phony... I know who I am siding with.
Deathclock
4.2 / 5 (23) Sep 12, 2012
Always curious too as to what wavelengths these investigators are talking about when they refer to "dark energy". All energy is composed of electro-magnetic lines of flux, it doesn't matter if you put "dark", "visible light", "infrared" or whatever other portion of the electro-magnetic spectrum in front of the word "energy".


No... what is the wavelength of potential energy? Kinetic energy? Chemical energy?

How about mass? Mass is energy, what wavelength range would you search to find mass?

Electromagnetic energy is only one of many forms of energy... Energy is the measure of a systems ability to do work, not all work is done in the form of EM radiation.
210
1.7 / 5 (6) Sep 12, 2012
Dark energy....dark matter...I would like to know, where it came from. What point in the expansion of the Universe did dark matter and energy begin? Did dark matter and energy have more to do with the expansion of the Universe than the big bang itself??

word-
adrianv
3.8 / 5 (5) Sep 12, 2012
I'm clearly a neophyte, but... " which is the most distant image of the Universe seen, some 46 billion light-years away" I thought the observable universe limit was only ~15 billion years?
cantdrive85
2.3 / 5 (19) Sep 12, 2012
Almost all cosmologists/astronomers/physicists think it's real, almost all cranks that spend all their time commenting on an obscure science republishing site think it is phony... I know who I am siding with.


A quote from the deity you bow down to;
"Unthinking respect for authority is the greatest enemy of truth." Albert Einstein
Pyle
4.2 / 5 (9) Sep 12, 2012
The 15 number is the age of the universe. The 46 size number reflects the expansion of the distance traveled. i.e. When the light left its source it was some distance less than 15 bln light years from where we are now. In the intervening time that space between where the light came from and here has expanded to 46 blyr.
To further confuse, light leaving Earth now would never reach the cmbr's source given acc expansion.
Deathclock
4.1 / 5 (22) Sep 12, 2012
A quote from the deity you bow down to;
"Unthinking respect for authority is the greatest enemy of truth." Albert Einstein


Appeal to authority fallacy is only a fallacy when the appeal is made to a person who's authority is not in a relevant field or topic. Authorities are brought to the witness stand to testify all the time and the strength of their testimony lies with their authority in a field relevant to the case and to the testimony that they are providing.

An example of appeal to authority fallacy: "Richard Dawkins thinks that dark energy exists and he is a respected scientist."

The problem here is that Richard Dawkins is an evolutionary biologist... he is not an authority in the field of cosmology.

NOT an example of appeal to authority fallacy: "Lawrence Krauss thinks that dark energy exists and he is a respected scientist."

Lawrence Krauss is a theoretical physicist... dark energy falls within his area of expertise.

Get it?
HannesAlfven
2.1 / 5 (19) Sep 12, 2012
Re: "Almost all cosmologists/astronomers/physicists think it's real, almost all cranks that spend all their time commenting on an obscure science republishing site think it is phony... I know who I am siding with."

It's difficult to take dark energy seriously for a couple of reasons -- foremost, (1) Because they refuse to dedicate any serious human or telescope resources to Halton Arp's work, which provided us with ample reason to investigate an additional -- possibly age-related -- inference for redshift. Age-related redshifts would be very easy to confuse for velocity-related redshifts. The notion that redshift can only occur due to one physical cause is extremely sloppy work, considering that we also observe redshifts with critical ionization velocities.

We see bridges connecting objects of vastly different redshifts. For instance, even though NASA routinely crops their images of Stephan's Quintet to exclude the area where this tail would be seen, it has been captured.

[contd]
HannesAlfven
1.8 / 5 (16) Sep 12, 2012
[contd]

The connecting bridges of Stephan's Quintent can be observed halfway down Don Scott's page on Halton Arp ...

http://electric-c.../arp.htm

But also, (2) There remain a lot of questions about the Type 1a supernovae. From "Surveys of Exploding Stars Show One Size Does Not Fit All" ...

"Type Ia supernovae are regular enough that astronomers can use them to measure the universe. But some of the "standard candles" are breaking the theoretical mold. When astronomers wish upon a star, they wish they knew more about how stars explode. In particular, experts on the stellar explosions known as supernovae wonder whether textbook accounts tell the true story."

... and ...

""We put the theory in the textbooks because it sounds right. But we don't really know it's right, and I think people are beginning to worry," says Robert Kirshner, a supernova researcher at the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Massachusetts"

[contd]
cantdrive85
2.2 / 5 (17) Sep 12, 2012
I stopped watching 'Family Feud' when Richard Dawkins died.

And Ptolemy was a respected astronomer and insisted that the Earth was the center of the Universe.
I get it, sometimes the emperor is nude.
HannesAlfven
1.9 / 5 (13) Sep 12, 2012
[contd]

"Kirshner was among more than 100 experts on stars and their explosions who gathered to discuss their worries last month at the Kavli Institute for Theoretical Physics at the University of California, Santa Barbara. General agreement emerged that the textbook story "is a little bit of 'the emperor has no clothes,' " as Lars Bildsten, an astrophysicist at the Kavli Institute, put it.

"There's a lot of holes in the story." "I wouldn't say it's a crisis," [Kirschner] said. "But if you ask, 'Are the pieces falling into place?' I'd say the answer is no." Understanding type Ia supernovae has become an urgent issue in cosmology, as they provide the most compelling evidence that the universe is expanding at an accelerating rate."

--

That these contradictory pieces of data have to appear in the comments posted by non-scientists -- rather than by science journalists within the article itself -- is arguably part of the problem which people should be discussing here ...
Tuxford
1.4 / 5 (17) Sep 12, 2012
The very slight blue shift in the presence of matter is exactly the prediction of LaViolette's SubQuantum Kinectics. In intergalactic space, the red shift is observed, as photons loose energy directly to another dimension, essentially escaping our universe. In this model, our detectable universe is a subset of a larger thermodynamic realm. In this way, First Law is upheld. Physics is simply blinded by a lack of imagination, resulting is wild mis-interpretations, such as the Big Bang Fantasy. I prefer Disneyland.

The slight discrepancy in summing the sources of the Pioneer anomaly is likely attributable to this slight gain in photon energy within our solar system. Further data will be needed to confirm.
Deathclock
3.6 / 5 (17) Sep 12, 2012
And Ptolemy was a respected astronomer and insisted that the Earth was the center of the Universe.


Cool, nice strawman... I never said experts can't be wrong. I said when given the opinion of a bunch of experts vs. a bunch of nobodies only the fool would bet on the nobodies because statistically the experts will be correct and the nobodies will be wrong the vast majority of the time.
HannesAlfven
2.4 / 5 (17) Sep 12, 2012
Re: "In intergalactic space, the red shift is observed, as photons loose energy directly to another dimension"

I'm all in favor of investigating against-the-mainstream theories, but has it occurred to you that alternative dimensions are extremely useful for theorists who are struggling to get their math to work? If Arp is right, then we can explain redshift without the need for metaphysical inferences.

It's interesting what people decide to reject, when they turn on mainstream theory. Mainstream theory is forced to look to invisible entities like alternative dimensions, dark matter, dark energy, black holes and magnetic fields in order to make a holistic presentation for how the universe works. But, they do so out of need, because their theories are not working. People who distrust mainstream science oftentimes make the apparent mistake of rejecting mainstream theory, but keeping the fudge factors as tools. In truth, the fudge factors should be rejected *with* mainstream theory
Shootist
2.5 / 5 (15) Sep 12, 2012
Until we know what it is, we don't know anything. This is a very poor attempt by these astronomers to prove anything.


You're wrong. There is no other way to say it.

We don't know what magnetism is.
We don't know what inertia is.
You don't know where your butt is and you're looking for it with both hands.
cantdrive85
1.8 / 5 (19) Sep 12, 2012
And Ptolemy was a respected astronomer and insisted that the Earth was the center of the Universe.


Cool, nice strawman... I never said experts can't be wrong. I said when given the opinion of a bunch of experts vs. a bunch of nobodies only the fool would bet on the nobodies because statistically the experts will be correct and the nobodies will be wrong the vast majority of the time.

That's fine, but how in the world can someone be an expert in something that is not there?
Deathclock
3.1 / 5 (16) Sep 12, 2012
That's fine, but how in the world can someone be an expert in something that is not there?


Oh are you going to resort to being ridiculous when backed into a corner too? Are you sure you're not a sock puppet of VD?

dark matter/energy falls within the realm of physics and cosmology. Experts in the fields of physics and cosmology claim it exists... you, a nobody on an obscure science news site, claim it does not exist, because you probably don't even understand what the experts claim to know about it.

The term "dark" was given to these things to signify that we cannot directly detect them, they are inferred from their effects. The experts KNOW THIS and accept this, but this is true of many things, including gravity, magnetism, and EM radiation (actually, if you want to get into epistemology, everything is "only" inferred by effect).
HannesAlfven
2.3 / 5 (12) Sep 12, 2012
Re: "I said when given the opinion of a bunch of experts vs. a bunch of nobodies only the fool would bet on the nobodies because statistically the experts will be correct and the nobodies will be wrong the vast majority of the time."

Actually, as a philosophy, this approach would have precluded Einstein from having any say. Have you considered that you're advocating for taking a survey of experts for the simple reason that we are all trained as specialists, and science has become so overwhelmingly large that specialization leaves us *dependent* upon these experts?

Rather than culture our dependency upon experts, why don't we go to the root of the problem? Physics education research has offered a variety of solutions to this problem already. See the work of Eric Mazur and Joseph Novak. It seems to me that the forum format is especially incapable of handling discussions of complex topics. If that wasn't the case, then you wouldn't be suggesting that we poll scientists.
HannesAlfven
2.1 / 5 (11) Sep 12, 2012
Also, re:polling the experts, you might want to check out the YouTube documentary, "The Trouble with Experts" ...

http://www.youtub...wQdo3sg4

There are no easy fixes to information overload. Critical thinking is unavoidable if accuracy of knowledge is valued, and a central component of critical thinking involves listening to critics. If our entire country decides to only culture an interest and knowledge of popular notions in science, then all that we can truly be sure of is that innovation will suffer in the long-term -- because psychologists will tell you that change is very hard, and as a result, it oftentimes is forced upon insiders by outsiders. One need only look to Einstein's story to see that it's true.
adrianv
3.5 / 5 (2) Sep 12, 2012
The 15 number is the age of the universe. The 46 size number reflects the expansion of the distance traveled. i.e. When the light left its source it was some distance less than 15 bln light years from where we are now. In the intervening time that space between where the light came from and here has expanded to 46 blyr.
To further confuse, light leaving Earth now would never reach the cmbr's source given acc expansion.


I'm still not quite sure how that works. If the age of the universe is 15Byrs, then at most the total lightspeed-diameter is 30Byrs, and our horizon off to one side is woefully reduced. How do they get to 46Byrs? Sorry, stupid question, I know, but please help!
antialias_physorg
4.6 / 5 (5) Sep 12, 2012
I'm still not quite sure how that works. If the age of the universe is 15Byrs, then at most the total lightspeed-diameter is 30Byrs,

The universe is not static. It expands.
indio007
1.4 / 5 (9) Sep 12, 2012


Appeal to authority fallacy is only a fallacy when the appeal is made to a person who's authority is not in a relevant field or topic. Authorities are brought to the witness stand to testify all the time and the strength of their testimony lies with their authority in a field relevant to the case and to the testimony that they are providing.


Appeals to authority are fallacies in ALL cases.
cantdrive85
1 / 5 (10) Sep 12, 2012
That's fine, but how in the world can someone be an expert in something that is not there?


Oh are you going to resort to being ridiculous when backed into a corner too? Are you sure you're not a sock puppet of VD?

dark matter/energy falls within the realm of physics and cosmology. Experts in the fields of physics and cosmology claim it exists... you, a nobody on an obscure science news site, claim it does not exist, because you probably don't even understand what the experts claim to know about it.

The term "dark" was given to these things to signify that we cannot directly detect them, they are inferred from their effects. The experts KNOW THIS and accept this, but this is true of many things, including gravity, magnetism, and EM radiation (actually, if you want to get into epistemology, everything is "only" inferred by effect).

At least you acknowledge his "expertise" is based on inferences and assumptions, that's how I became an expert too.
antialias_physorg
5 / 5 (12) Sep 12, 2012
Appeals to authority are fallacies in ALL cases.

I think what he's saying is that when you have to bet on whether someone with a proven track record of getting stuff right and having in-depth knowledge in a subject vs. someone who just voices an uneducated opinion, then its prudent to go with the one who's got the track record.

It's a bit lie with the arm-chair coaches. I'm certain they all are convinced that they'd do an oh-so-much-better job at coaching their favorite team.

But given the choice of sticking with a coach that has led past teams to championships and some armchair slob that hasn't ever picked up a ball - who would YOU go for?

All opinions are not equal. The informed opinion beats the uninformed one most any day.
Deathclock
4.1 / 5 (14) Sep 12, 2012
At least you acknowledge his "expertise" is based on inferences and assumptions, that's how I became an expert too.


See... the problem is you have no clue what you are talking about. The terms "dark matter" and "dark energy" refer only to the observed EFFECTS... The EFFECTS are real, they have been observed... we are still trying to find out the causes of those effects.

Matter and energy are interchangeable, mass-energy equivalency. Further, matter/energy is ALL that exists, everything is matter/energy. So "dark matter/energy" is merely referring to SOMETHING that causes an affect that we observe.

Do you understand now? The terms only refer to the observations that have been made... the fact that we don't know exactly what caused these effects is INHERENT in the definition of the terms.
Deathclock
3.9 / 5 (15) Sep 12, 2012
Appeals to authority are fallacies in ALL cases.


You're simply wrong, read:
http://en.wikiped...uthority

"Fallacious arguments from authority often are the result of failing to meet at least one of the required two conditions (legitimate expertise and expert consensus)"

This means that if you have legitimate expertise and expert consensus then the appeal to authority is NOT FALLACIOUS.

Why must I always take the role of educator of basic concepts in these discussions?
Deathclock
3.8 / 5 (13) Sep 12, 2012
If we observe an effect then it is necessarily true that some matter/energy caused it, because matter/energy is ALL THAT EXISTS. Dark simply refers to the fact that we are not sure what it is...

When you UNDERSTAND what the terms mean you realize how stupid you are to claim it doesn't exist... which is really just claiming that the observations were not real.
Deathclock
3.5 / 5 (11) Sep 12, 2012
Hell, for all intents and purposes gravity might as well be called dark energy. Same for EM radiation and magnetism. When you get right down to it we don't really know what any of these things "are"... we only know what they do. (Perhaps what they are is fully defined by what they do?)
Torbjorn_Larsson_OM
4.5 / 5 (12) Sep 12, 2012
Nice, though I don't think the opposition to dark energy has been as strong as alluded to here. It is called the "standard cosmology" for a reason.

"there is a 99.996 per cent chance that dark energy is responsible for the hotter parts of the cosmic microwave background maps (or the same level of significance as the recent discovery of the Higgs boson)."

Though accelerators fight data fishing ("look elsewhere") effects, which makes 5 sigma needed for hypothesis testing. 3 sigma works excellent elsewhere, so this is overkill.

@ AWaB:

It is called dark energy because it is a stress-energy ("energy) term in the general relativity description of standard cosmology, and because it isn't an EM effect ("dark").

And we do know a lot, for example these observations and the standard cosmology prediction it tests.
Torbjorn_Larsson_OM
4.5 / 5 (13) Sep 12, 2012
@ Benni:

No, it isn't gravity (mass source) as much as spacetime (space-time vs stress-energy sources) in general relativity. GR is an inclusive gravity theory, predicting classical gravity as part of spacetime.

DE is observed from various effects including EM, so to ask "which wavelengths" is not pertinent.

@ adriany:

Precisely! DE (and inflation) has blown up the universe in scale non-linearly compared to freewheeling linear expansion. [ http://en.wikiped...universe ]

@ HannesAlfvén:

Arp's ideas are rejected long ago, doesn't stand up to observation.

DE does, see the article.
Torbjorn_Larsson_OM
3 / 5 (4) Sep 12, 2012
Oops. "an inclusive gravity theory" - an extended gravity theory.

"freewheeling linear expansion" - freewheeling non-accelerating expansion. (The difference comes in the new forcing, DE is accelerating expansion.)
wkrasl
3 / 5 (2) Sep 12, 2012
I'm still not quite sure how that works. If the age of the universe is 15Byrs, then at most the total lightspeed-diameter is 30Byrs,

The universe is not static. It expands.


Interesting ... I never thought of the rate of expansion being quite that fast. I also questioned depiction of the universe at 46B light year radius. My reasoning is that we are repeatedly told it is only about 17B years old, and since nothing travels faster than light, the max possible distance any part of the universe (photon or otherwise) could have traveled from big bang to today is the universe age in light years.

In fact, most lay explanations use the analogy of the 2D surface of an expanding balloon -- Looking in any 2D direction following a great circle on that balloon surface looks towards the point singularity of the big bang on the exact opposite side of the balloon 17B light years away.

So would FTL expansion have caused that point to NOW be 92B * 2pi light years away?
wkrasl
4 / 5 (2) Sep 12, 2012
... oops ... I meant the distance of a semicircle following the surface, so that would be only r * pi, so the point singularity of the big bang would now be 46B times pi light years away.

Yes, I am thinking of a 4D sphere with space being a 3D expanding surface. Thanks for allowing the analogy. :)
Tuxford
1.8 / 5 (5) Sep 12, 2012
I'm all in favor ..., but has it occurred to you that alternative dimensions are extremely useful for theorists who are struggling to get their math to work?


I agree that alternative dimensions belongs in the realm of math, but this is my attempt to reach the simple-minded. In fact, this theory is based on dynamic systems science, which was unavailable until the advent of computers. Thus, classical physics is stuck in mechanics, and is clueless to dynamic systems analysis. I think classical EE's may have a chance, who have closed servo loops. Others no way. The evidence is in the reactions here.

The dimension operates within our 3-D universe, but is simply the TOO small to be detectable. The self-sustaining diffusive etheric reactions themselves are each a sub-atomic particle. Thus, the underlying etheric components can never be detected, only inferred though an understanding of feedback systems. Call it the transmutation dimension, if it helps.
julianpenrod
1.4 / 5 (9) Sep 12, 2012
Perlmutter's group said certain Type 1a supernovas were dimmer "than they should be". The dimness they "should be" depends on the distance to the galaxies derived from their redshift speed of recession. Therefore, the "coindluded", the galaxies were going "faster than they should be". In other words, they were receding faster than their speed of recession! That's the "logic" the Perlmutter group used!
And, too, the galaxies supposedly moving so anomalously fast were five billion light years away. Those closer in, and later in the age of the universe, move according to the lower Hubble Constant! That's why the distant galaxies are claimed to move faster, because those later in history move slower! That means that they are not accelerating! Galaxies are moving slower now than those five billion years ago. Perlmutter is a fraud.
So many will attack the Obama Nobel Prize but refuse to question Perlmutter's!
wkrasl
5 / 5 (3) Sep 12, 2012
Hmmm ... I was using 17B years above. Just looked it up and see I should have been using 13.7B years. Thanks.
Pressure2
1.8 / 5 (4) Sep 12, 2012
The 15 number is the age of the universe. The 46 size number reflects the expansion of the distance traveled. i.e. When the light left its source it was some distance less than 15 bln light years from where we are now. In the intervening time that space between where the light came from and here has expanded to 46 blyr.
To further confuse, light leaving Earth now would never reach the cmbr's source given acc expansion.


I'm still not quite sure how that works. If the age of the universe is 15Byrs, then at most the total lightspeed-diameter is 30Byrs, and our horizon off to one side is woefully reduced. How do they get to 46Byrs? Sorry, stupid question, I know, but please help!

Also don't forget there was an inflationary period right after the BB that almost instantly expanded the universe to, well to whatever size is currently needed to make everything else work.
Pressure2
1.6 / 5 (5) Sep 12, 2012
... oops ... I meant the distance of a semicircle following the surface, so that would be only r * pi, so the point singularity of the big bang would now be 46B times pi light years away.

Yes, I am thinking of a 4D sphere with space being a 3D expanding surface. Thanks for allowing the analogy. :)

What you are not figuring is that there was this magical period right after the BB in which the universe was able to expand at a million(?) times the speed of light. That is the reason given as to why we observe a flat universe today.
HannesAlfven
1.4 / 5 (9) Sep 12, 2012
Re: "Arp's ideas are rejected long ago, doesn't stand up to observation."

Arp's ideas were ruled out before they were even funded. In fact, one of the initial rejections of Arp's hypothesis claimed that astronomers could find no quantization effects in the observed redshift values of quasars. The problem is that the researchers did not listen carefully to what Arp was saying, and they actually published a paper which looked for quantization in the RAW redshift values of quasars. Unfortunately, the raw measured total redshift values of the universal set of all known quasars are not quantized. It is the INHERENT redshift z values that are quantized. See http://electric-c...arp.htm.

This is what happens when people are dismissive of anything which is unconventional.

Ignoring Arp demands that we believe that quasars can shine THROUGH galaxies, from enormous distances. It also demands that we believe that quasars are METAPHYSICALLY bright, compared to all other objects.
HannesAlfven
1.4 / 5 (9) Sep 12, 2012
Mainstream theorists argue that Arp's observations aren't even worth investigating. Put another way, they are claiming that it is OBVIOUS that quasars should be able to shine through galaxies, and that -- by contrast -- it is UNBELIEVABLE that the quasars are simply in front of those galaxies. Why? Because (1) they point to some statistics, which only a small number of people would be able to refute, and (2) because of the ASSUMPTION that redshift can only have one underlying physical cause. It should be blatantly clear that neither of these arguments are in fact strong arguments.

We are also told that, on those numerous occasions where we can see the quasar at the end of a filament connected to a galaxy, that these are all "chance" alignments.

What happens when people reject Arp is that they permit themselves to not learn Arp. Thus, as new observations support him, they fail to realize it. And all they can say are things like, "Arp's ideas are rejected long ago."
ValeriaT
1 / 5 (9) Sep 12, 2012
The wavelength of ripples at the water surface expands with increased speed, thus mimicking the dark matter effect with water surface analogy of the space-time. When we consider the Le-Sage shielding model of gravity, then the (cold) dark matter is the result of shielding of this shielding with nearby objects. And because the nearby objects are missing at the boundaries of observable Universe scope, the dark matter effect can be derived even with shielding model.
Caliban
1.9 / 5 (9) Sep 12, 2012
The Big Bang continues, and the visible universe is the condensate left in the wake of the expanding wavefront --the collapsed remnant or derivative in four dimensions of the state that existed immediately prior to the event.

The CMB is redshifted to hell and back because we are accelerating away from IT --because it is, in fact, the BB itself, which is ONGOING, even though we like to think that it was a discrete, one-time event that occurred about 14GYA.

How about that, kiddies?

PinkElephant
3.7 / 5 (3) Sep 12, 2012
@adrianv, wkrasl,

The universe has been expanding all the while the most ancient of the photons have been traveling toward us.

Imagine a photon traveling from its origin at point A to point B. As the photon begins traveling form A to B, both A and B start to simultaneously fly away from the midpoint between them at some relative velocity v. Say the photon reaches B at time t -- what is the *actual* distance between A and B by then? Well, if the initial distance when the photon just started out was c*t (where c is speed of light), the new distance is the sum of c*t and v*t.

The analogy isn't exact (in reality A and B aren't flying away from each other, rather the space between them is expanding at all points; v isn't a constant either but a function of gravitational contraction and DE-driven expansion.)

But maybe you can see how the actual distance to the observable horizon is much greater today than just c*T (where T is the age of the universe.)
kochevnik
1.5 / 5 (8) Sep 12, 2012
@Deathclock Matter and energy are interchangeable, mass-energy equivalency. Further, matter/energy is ALL that exists, everything is matter/energy. So "dark matter/energy" is merely referring to SOMETHING that causes an affect that we observe.
You say they're interchangeable but you're biased against the transformation. Thirteen hammerheads downvoted my post, which is hilarious because I actually offered a counterexample to dark matter. Dark matter enthusiasts are all a crowd of barking seals. The reality is that gravity induces a phase change in space to effect matter. It begins with hydrogen and more complex elements which precipitate onto massive bodies like planets. That's why all planets have atmospheres. This phased space is your so-called dark matter. That's why perfectly-balanced log-spiral galaxies don't harbor dark matter. They form a perfectly balanced neutral center.
Benni
1 / 5 (10) Sep 12, 2012
@ Benni:

No, it isn't gravity (mass source) as much as spacetime (space-time vs stress-energy sources) in general relativity. GR is an inclusive gravity theory, predicting classical gravity as part of spacetime.

DE is observed from various effects including EM, so to ask "which wavelengths" is not pertinent.


And you don't have the faintest idea of what you're talking about. All energy has a wavelength in the electro-magnetic spectrum, or, it can't be energy. Photons are energy, there are no "potential" photons that can form energy, either the photons are there or they aren't, & if they are not there is no energy present.

In looking over so many of the posts between this one & my first one, I can easily tag the handle names of the posters who've never had a course in thermodynamics.
MrVibrating
5 / 5 (4) Sep 12, 2012
The wavelength of ripples at the water surface http://people.rit...565.jpg, thus mimicking the dark matter effect with water surface analogy of the space-time. When we consider the Le-Sage shielding model of gravity,
Sorry but the ripple analogy's broken - wavelength decreases inversely to radiative diameter, conserving energy / momentum; the speed is a constant function of density and viscosity of the medium, ie. short and long wavelengths propagate at equal speed, and radiating waves don't diverge or converge with respect to their neighbors as they trade wavelength for radius - they maintain phase. Thus your premise is mistaken.

Furthermore your apparent conclusion in support of radiative gravity seems completely irrelevant.. besides, how does the shielding vary in relation to mass, density and size? Gravity is mass dependent, not size dependent..!?
PinkElephant
4.7 / 5 (12) Sep 12, 2012
@Benni,
All energy has a wavelength in the electro-magnetic spectrum, or, it can't be energy.
...
In looking over so many of the posts between this one & my first one, I can easily tag the handle names of the posters who've never had a course in thermodynamics.
Apparently you've never heard of either potential energy or kinetic energy (to name just a couple known to all who completed even the most rudimentary physics class in High School...) Perhaps as a prerequisite for your alleged education in thermodynamics, you should've covered the barest fundamentals of Newtonian kinematics? Just a thought...
MrVibrating
4.5 / 5 (10) Sep 12, 2012
I can easily tag the handle names of the posters who've never had a course in thermodynamics.
Yes... and as Torbjorn noted, energy is the potential to perform work. It is force multiplied by displacement / distance, where the force in question determines the form of energy - mechanical, nuclear, EM etc. So a pen on your desk has mechanical potential energy equal to its mass times your desk's height, times the rate of acceleration of gravity, per Newton. What's its wavelength then? Where's its EM component? You're talking gibberish. I was tempted to answer your initial post but i've already covered this with you before... tho FWIW magnetism is not simply low frequency EM radiation, as you stated therein, and again, photons are massless; EM radiation does not gravitate, besides as Torbjorn pointed out if DE was EM it wouldn't be DE by definition! Duh... If experience is anything to go by this is where you tell me to go read "physics 102" as you call it (link please?)..
MrVibrating
4.6 / 5 (9) Sep 12, 2012
Oh, and again, Benni, DE is repulsive. Gravity is that other one.. what's it called, oh yeah "attractive".. They're like, opposites, or something, i think...
PinkElephant
5 / 5 (8) Sep 12, 2012
EM radiation does not gravitate
Actually, it does. Photons have no rest mass (because measuring them in their own reference frame is impossible, since no measuring apparatus can attain light speed), but they do have gravitational/inertial mass (and as a consequence, they have momentum and gravity, though the latter is exceptionally weak due to the m=e/c^2 relationship.) Everything in the universe gravitates, without exception (EM radiation and matter are equivalent and interconvertible, after all.) If somehow you managed to get enough photons concentrated densely enough together, you could create a black hole. In that sense, black holes are the hottest objects possible (the highest concentrations of energy allowable.) For instance that means when a black hole traps an incoming photon, it does get that tiniest bit larger.
lengould100
1 / 5 (2) Sep 13, 2012
either confirming general relativity, including dark energy, or even more intriguingly, demanding a completely new understanding of how gravity works.


Thats the key statement to me. It seems very logical that rather than conjecturing about some wierd 97 % of material (matter) in the universe being undetectable dark matter and energy, we should first evaluate the liklihood (very high IMHO) that our theories of how gravity works, especially at great distances, are missing a few factors. Last I read, some mavericks have already completely eliminated the need for dark matter, simply by adding an additional term to current gravity equations.

charles_shults
4.6 / 5 (5) Sep 13, 2012
@Benni - "All energy is composed of electro-magnetic lines of flux, it doesn't matter if you put "dark", "visible light", "infrared" or whatever other portion of the electro-magnetic spectrum in front of the word "energy"."

This is incorrect. Only electromagnetic energy falls in this category. There are three other forces that we know about and they do not operate using EM fields or photons yet they transfer forces and react to them. Dark energy is another thing still, and we can only detect it through its mass effects.

@Shootist - we DO know what magnetism is, it is a change in the vacuum caused by the virtual photon field.

This is an interesting article and even with its flaws, it does convey the concept that there is a pervasive influence on the structure of the universe that is not accounted for by the four known forces. Dark matter and dark energy apparently have enough mass to curve spacetime, but it is still possible that something else is doing it.
enigma13x
1 / 5 (1) Sep 13, 2012
i would just like to know if the universe is expanding in what direction is it expanding because from no matter what point on the earth you look out in to space according to the red shift everything is moving away from us at the same speed unless we are the center of the big bang that makes no sense can some one please explain / justify this problem to me
lengould100
1 / 5 (1) Sep 13, 2012
http://en.wikiped...ysicist)

John Moffat - book ReInventing Gravity.

Does Higgs boson really exist, and can Moffats theories be adjusted to accomodate if so.
TheWalrus
5 / 5 (4) Sep 13, 2012
It always amuses me to read the desperately ignorant rantings of uneducated armchair "scientists" who have no credentials, no math, no research, no reason for anyone to take them seriously, who somehow think that their anonymous opinions on the Internet are superior to real scientists who did real research, and who can put their math where their mouth is.

You people are pathetic.
cantdrive85
2.1 / 5 (7) Sep 13, 2012
@ Benni:

In looking over so many of the posts between this one & my first one, I can easily tag the handle names of the posters who've never had a course in thermodynamics.

Thermodynamics is not what should be use to describe space plasma, magnetohydrodynamics is what needs to be used, this is why the standard theory claims missing mass and fails to explain galaxy rotation and such. A simple application of the proper force laws and acknowledge Mr. Arp's observations, the need for dark matter/energy cease to exist.
That's when we remember Occam's Razor; " one should not increase, beyond what is necessary, the number of entities required to explain anything"
cantdrive85
1 / 5 (3) Sep 13, 2012
@Shootist - we DO know what magnetism is, it is a change in the vacuum caused by the virtual photon field.

What? You need to discuss EM Theory with someone who has a clue, you don't!
___as two short plancks_
1 / 5 (2) Sep 13, 2012
I may be off the mark here but I'll cast my line and see what bites...

String theory proposes 11 dimensions of hyper space which suggests that there are 8 dimensions above our own.

.*. 8/11 = 73%.
Pressure2
1.4 / 5 (5) Sep 13, 2012
i would just like to know if the universe is expanding in what direction is it expanding because from no matter what point on the earth you look out in to space according to the red shift everything is moving away from us at the same speed unless we are the center of the big bang that makes no sense can some one please explain / justify this problem to me

I cannot justify it for you but I will give you the currently accepted reason. The inflationary period in the first fraction of a second after the BB expanded the universe to a minimum radius of 13.7 billion light-years. It could have expanded much bigger than this, we just do not know. But this is the reason given as to why everything looks the same in every direction we look into the universe. The universe is flat.
antialias_physorg
3.7 / 5 (3) Sep 13, 2012
I cannot justify it for you but I will give you the currently accepted reason. The inflationary period in the first fraction of a second after the BB expanded the universe to a minimum radius of 13.7 billion light-years.


While cosmic inflation was very rapid, it occured only for a tiny amount of time. The universe was, after the inflationary period, only about 10cm accross.
http://aether.lbl...ers.html

i would just like to know if the universe is expanding in what direction is it expanding

It is not inflating INTO anything (as you seem to assume). It is expanding. This means that every spatial point in the universe is undergoing an expansion movement (this does not mean that massive objects, like your body, are getting bigger as the size and distances of bound atoms are quantized). This is why wherever you look you see light from the CMBR arrive just now (after 13.7bn years) but from an origin much farther away than 13.7bn light years.
animah
5 / 5 (3) Sep 13, 2012
enigma13x, try this: Put evenly spaced dots on an uninflated balloon with a marker, then blow it up. As it expands, you will notice that all the dots pull away from each other.

From the standpoint of any dot, all other dots on the balloon are pulling away. Every dot is the centre - the surface itself has no centre.

The balloon's surface is a 2D analog of our 3D universe.

Also imagine a point (e.g. photon) trying to travel from one dot (e.g. star) to another as the balloon expands. It would have to "fight against" expansion to reach its target. Now look at the illustration at the top of the article. I think you can see why the CMBR diameter is a lot larger than 13.7bn LY, and why one can calculate the universe's rate of expansion.
Pressure2
1 / 5 (1) Sep 13, 2012
AP quote: "While cosmic inflation was very rapid, it occured only for a tiny amount of time. The universe was, after the inflationary period, only about 10cm accross."
http://aether.lbl...ers.html

While what you state about time and rapidity is correct the size after the inflationary period would have to be at least the size of what we see in the present day universe. If not, the observable universe would not be flat, we would detect a difference in different directions. And that we do not do.
antialias_physorg
not rated yet Sep 13, 2012
If not, the observable universe would not be flat

Why? I don't see how flatness requires a minimum size of billions of light years from rapid expansion. It just requires an expansion over many orders of magnitude from the initial state.
After that you get no difference by looking in different directions. We're not talking explosion. We're talking inflation.
Pressure2
1 / 5 (2) Sep 13, 2012
If not, the observable universe would not be flat

Why? I don't see how flatness requires a minimum size of billions of light years from rapid expansion. It just requires an expansion over many orders of magnitude from the initial state.
After that you get no difference by looking in different directions. We're not talking explosion. We're talking inflation.

The reason the inflation period would have had to expand the universe to the minimum size of the universe we observe today is because all the light we see that originated since the BB (13.7 BY's)comes to us in straight lines. If it did not we would observe different densities in the cosmic back ground radiation depending on the direction we look.
mpc233
1 / 5 (3) Sep 13, 2012
The Universe, or our local Universe, is a larger version of a black hole polar jet.

Dark energy is aether emitted into the Universal jet.

It's not the Big Bang; it's the Big Ongoing.
Q-Star
2.8 / 5 (6) Sep 13, 2012
The phrase hyperbolic-grandiose-delusions come to mind after reading some of the pronouncements here. (Or maybe it is the effect of drugs on the ego,,,???) Organic or chemical, it's still foolishness.

I realize it would be embarrassing to be seen reading one, maybe you could paper over the covers,,,, but some of you people are in dire need of an "Idiot's Guide" or a "For Dummies" book or two.

If you have no idea what you're talking about, don't get mad if no one else knows what you're talking about either.
ValeriaT
1 / 5 (4) Sep 13, 2012
wavelength decreases inversely to radiative diameter, conserving energy
It doesn't - just check my picture again. The energy during scattering is not conserved for surface waves - it's dissipated into underwater and vice-versa.
Q-Star
2.8 / 5 (5) Sep 13, 2012
[wavelength decreases inversely to radiative diameter, conserving energy
It doesn't - just check my picture again. The energy during scattering is not conserved for surface waves - it's dissipated into underwater and vice-versa.


He's right. You are wrong. Your underwater "system" is not a closed system. EM waves are not of the same stuff as water. Many great minds over the years have tried and all have failed,,, to find a situation where the conservation of energy-matter breaks down. If you have found an exception, I will be expecting a forthcoming Nobel award in your favor.

Psst, I'll give you a hint to get you started,,, water and EM are different physics, you'll be needing separate explanations for how each acts. Sort of like using a Porche service manual to do heart surgery,,, it won't make you look good at auto repair or doctoring.
MrVibrating
1 / 5 (1) Sep 13, 2012
Actually, it does. Photons have no rest mass (because measuring them in their own reference frame is impossible, since no measuring apparatus can attain light speed),
They're massless because they instantaneously propagate at C, which would be impossible if they had mass. They're not "massless because we can't measure them".

but they do have gravitational/inertial mass (and as a consequence, they have momentum and gravity, though the latter is exceptionally weak due to the m=e/c^2 relationship.)
They have relativistic mass, AKA radiation pressure. This is a force applied to matter they interact with. For example it's the force inflating stars against gravity, the cessation of which (due to fuel exhaustion) causes stellar collapse. Your assertion would thus have it that stars are supported against gravitational collapse by.. additional gravity? Anti-gravity? It's neither, but simply radiation pressure, caused by relativistic mass, which doesn't invoke gravity...
MrVibrating
3 / 5 (4) Sep 13, 2012
Everything in the universe gravitates, without exception
But photons don't interact with the Higgs field, they're massless. Gravity is an effect of interacting masses.
(EM radiation and matter are equivalent and interconvertible, after all.)
you're thinking of mass and energy.
If somehow you managed to get enough photons concentrated densely enough together, you could create a black hole.
Suppose we have a gravitating mass, and we convert some of it to energy, say EM energy, radiated away as photons... thus we have that much less gravitating mass left. The photons don't gravitate because they're massless, ie. because they're now energy, not mass. We converted one to the other. In the former, mass state, it was subject to gravity. In the EM state it is not subject to gravity. It'll follow a straight line though space, even if the space is warped, but that's not gravitating either - something else must first curve the space. Something 'massive'...
MrVibrating
2.3 / 5 (3) Sep 13, 2012
In that sense, black holes are the hottest objects possible (the highest concentrations of energy allowable.) For instance that means when a black hole traps an incoming photon, it does get that tiniest bit larger.
It gets warmer, sure, but heavier? Black holes trap photons because of the extreme spacetime curvature - not because photons get "sucked in" under a mutual attractive force, per gravity. If photons literally "fell" into gravity wells due to their own mass and mutual gravity, we'd be able to use lasers as tractor beams. Further, parallel beams in flat space would converge, light from distant galaxies would never reach us, instead getting attracting towards and trapped in either their own or intervening galactic cores..

Light does not gravitate, because it's massless. Relativistic mass describes the force applied by radiation pressure in terms of inertial equivalence, but a) gravity is not applicable, and b) the sign of the force is repulsive, not attractive.
MrVibrating
3 / 5 (4) Sep 13, 2012
Now, if we focus photons into a small point we could turn them back into massive particles, which'll then be subject to gravity. But photons themselves remain a massless form of matter.

This is a common misconception WRT equivalency. You'll occasionally hear claims that a loaded spring, for example, must weigh more than when unloaded - after all E=MC^2, right? Or that a fully charged battery outweighs a fully discharged one.

These misconceptions neglect that a spring only has energy relative to another mechanical body, or that a battery only has energy in relation to its charge separation or something connected to its terminals. The mass of such systems remains constant. Eg. suppose a falling weight powers an LED - does the mass weigh less after falling, in relation to the light emitted? Will it eventually evaporate over repeated cycles? Of course not.

Same disco with the "light must gravitate" meme on these boards...
Fleetfoot
4 / 5 (4) Sep 14, 2012
i would just like to know if the universe is expanding in what direction is it expanding because from no matter what point on the earth you look out in to space according to the red shift everything is moving away from us at the same speed unless we are the center of the big bang that makes no sense can some one please explain / justify this problem to me


Take a piece of clear film and draw some random dots on it. Photocopy it with a slight magnification say 101%. Lay the film over the copy and match up any dot on the film with its copy. All other dots will appear to have moved away from your reference by 1%. Now try matching a different dot, copy with original. The same pattern emerges. The Hubble Law works from everywhere, there is no unique centre.

Currently the universe is expanding by 1% in a little less than 200 million years.
Fleetfoot
4 / 5 (4) Sep 14, 2012
Everything in the universe gravitates, without exception
But photons don't interact with the Higgs field, they're massless.


Wrong way round, photons have no mass because the don't interact with the Higgs field the way other particles do.

Gravity is an effect of interacting masses.


The source term in GR is the stress/energy tensor. Gravity is created by energy and pressure. Mass is merely a bound form of energy.

Suppose we have a gravitating mass, and we convert some of it to energy, say EM energy, radiated away as photons... thus we have that much less gravitating mass left. The photons don't gravitate because they're massless, ie. because they're now energy, not mass.


A box full of photons with a perfectly mirrored interior has greater mass than the same box without the photons even though each photon has no mass. Mass is

m^2 = E^2 - |p|^2

For one photon E=|p| so m=0

For a box of photons the momenta partly cancel but the energies sum so m>0.
Fleetfoot
5 / 5 (4) Sep 14, 2012
Light does not gravitate, because it's massless. Relativistic mass describes the force applied by radiation pressure in terms of inertial equivalence ..


It's more complex. We know photons carry momentum, they push solar sails. We know they are deflected by gravitational lensing, hence for example if the Sun deflects a photon, it changes its momentum. If momentum is conserved, the Sun must have its motion changed to the photon has a gravitational effect on the Sun.

However, according to GR, photons do not interact with each other so parallel beams do not converge.

Note this has nothing to do with "relativistic mass" which is another topic entirley (and one of the least helpful concepts ever invented IMHO).
Fleetfoot
5 / 5 (3) Sep 14, 2012
The wavelength of ripples at the water surface expands with increased speed ..


The photo you have linked actually shows ripples from a source whose frequency decreased with time. However, if it was actually a speed effect, it would show the ripple wavelength and hence speed decreasing. You posted this several times now and still can't see that it shows is exactly the opposite of what you claim. Here's the one I did for you last time you posted this clueless nonsense:

http://www.flickr...7517344/
packrat
2.3 / 5 (3) Sep 14, 2012
Could someone explain how microwave radiation gains energy traveling though mass? In every example I've ever seen radio waves of every frequency attenuate when traveling though mass. The higher the frequency the greater the loss.
Fleetfoot
5 / 5 (2) Sep 15, 2012
Could someone explain how microwave radiation gains energy traveling though mass? In every example I've ever seen radio waves of every frequency attenuate when traveling though mass. The higher the frequency the greater the loss.


The photons in question are those that pass through the intervening galaxies without interacting with matter at all.

Think of the usual rubber sheet analogy for a gravtitational well in a flat background. A photon passing through gains energy going 'down' the slope and loses the same amount exiting. However, if the well is reduced in depth while the the photon is crossing the well, it loses less climbing out than it gained falling in, hence it receives an overall energy increase. There's a Wikipedia article on the effect here:

http://en.wikiped...e_effect
ValeriaT
2 / 5 (4) Sep 15, 2012
However, according to GR, photons do not interact with each other so parallel beams do not converge
The observations of distant gamma rays which contain the photons of different frequencies together at long distances but not at shorter ones may be explained just with mutual gravitational attraction of photons.
zaxxon451
1 / 5 (2) Sep 15, 2012
Hell, for all intents and purposes gravity might as well be called dark energy. Same for EM radiation and magnetism. When you get right down to it we don't really know what any of these things "are"... we only know what they do. (Perhaps what they are is fully defined by what they do?)


Interesting how we categorize things. We can't see the forest for the trees. Everything is one. Separateness is an illusion. Call the One what you like, "matter/energy", "God", "Self", "Brahman".
Fleetfoot
5 / 5 (4) Sep 15, 2012
However, according to GR, photons do not interact with each other so parallel beams do not converge
The observations of distant gamma rays which contain the photons of different frequencies together at long distances but not at shorter ones may be explained just with mutual gravitational attraction of photons.


As I said, there is no mutual effect in GR, nor is any explanation needed for a null result, the photon arrival times weren't widely separated.

They were however, spread over about a millisecond range which means they were about 300km apart in space while en route. That is far more than the mean spacing between, for example, CMBR photons, hence if there were any interaction at all, you would expect random deflections of photons to blur distant sources. The evidence confirms there is none.

What the gamma photon observations told us was that any velocity dispersion must be negligible which places constraints on some attempts to create a quantum theory of gravity.
Fleetfoot
not rated yet Sep 15, 2012
As I said, there is no mutual effect in GR, ..


I should perhaps qualify that, my understanding is that there is no interaction between individual photons which is what we are discussing here. The situation with aggregates is more complex.
rah
1.7 / 5 (6) Sep 15, 2012
The technical name for this kind of research is called bullshit.
ValeriaT
1.8 / 5 (5) Sep 15, 2012
As I said, there is no mutual effect in GR, nor is any explanation needed for a null result, the photon arrival times weren't widely separated
General relativity can say nothing about photons in general, because the photon is the concept of quite different theory, i.e. the quantum mechanics. The general relativity doesn't support the quantization, so it cannot say anything about photons.
Meyer
2.3 / 5 (3) Sep 16, 2012
Probably a crackpot idea here, but I welcome any insight:
If the velocity of a particle is known with 100% certainty, then the position should be 100% uncertain, no? If so, then wouldn't the particles at the edge of the observable universe approach the speed of light, shouldn't their positions smear out across the universe? So those distant particles would teleport (from various frames of reference) to other parts of the universe and collide with other particles, fueling the perpetual appearance of "expansion," though it would be more like a churn.
Mike_Massen
2 / 5 (4) Sep 16, 2012
MrVibrating offered re light & relativistic mass
It's neither, but simply radiation pressure, caused by relativistic mass, which doesn't invoke gravity
Which raises a question.
Since we theorise light cannot escape a black hole & we know light's deflected by gravity then isnt it conceivable, as it travels through space, it leaves a gravitational wake - no matter how small ?

Has anyone looked into the maths and physical consequences of this given # of photons ?

It would also be interesting to theorise how much time the photon experiences from the time its created to when its absorbed. The Lorentz factor becomes 1/0 which implies it 'limits to' infinity but perhaps, in that context 1/0 simply means that time (as far as the photon is concerned in its reference frame), does not apply, then suggesting it is zero. ie.The maths says 1/0, might this be another way of saying 0 since the maths is insufficient in that descriptive context to arrive at a numerical value we can relate to ?
Fleetfoot
4 / 5 (4) Sep 16, 2012
As I said, there is no mutual effect in GR, nor is any explanation needed for a null result, the photon arrival times weren't widely separated
General relativity can say nothing about photons in general, because the photon is the concept of quite different theory, i.e. the quantum mechanics. The general relativity doesn't support the quantization, so it cannot say anything about photons.


SR and QM have been successfully merged in QED. SR is the weak field limit of GR and the gravitational effect of a single photon would unquestionable be "weak"! In fact any possible interaction would be so small that the entire question is hypothetical anyway.
Fleetfoot
3.7 / 5 (3) Sep 16, 2012
The technical name for this kind of research is called bullshit.


You are slightly confused, that is the correct term for your contribution (and those of several crank posters), not the original article.
Fleetfoot
3.7 / 5 (3) Sep 16, 2012
Since we theorise light cannot escape a black hole & we know light's deflected by gravity then isnt it conceivable, as it travels through space, it leaves a gravitational wake - no matter how small ?

Has anyone looked into the maths and physical consequences of this given # of photons ?


Yes, the early universe was radiation-dominated so it is a standard part of the standard solution to the Friedmann Equations to include the gravitational effect of photons.

It would also be interesting to theorise how much time the photon experiences from the time its created to when its absorbed. The Lorentz factor becomes 1/0 which implies it 'limits to' infinity but perhaps, in that context 1/0 simply means that time (as far as the photon is concerned in its reference frame), does not apply, then suggesting it is zero.


Correct, the path of a photon is called a "null geodesic" because it is of zero length and duration. Any tutorial on relativity should cover that.
Fleetfoot
5 / 5 (2) Sep 16, 2012
Probably a crackpot idea here, but I welcome any insight:
If the velocity of a particle is known with 100% certainty, then the position should be 100% uncertain, no?


No, the uncertainty principle relates position to momentum. The speed is known but the momentum of a photon depends on its frequency, not its speed.

If so, then wouldn't the particles at the edge of the observable universe approach the speed of light, shouldn't their positions smear out across the universe?


You still don't know their momentum because it goes to infinity as the speed approaches c. Anyway, how do you propose to measure the momentum of a particle which is now at the edge of the observable universe, light from it won't get here for billions of years?

If the momentum of a photon were known exactly then so would its frequency, and the frequency of a sine wave can only be known exactly if it is measured for an infinite time. Multiply by the speed and the wave must be infinitely long.
Fleetfoot
not rated yet Sep 16, 2012
Probably a crackpot idea here, but I welcome any insight:
If the velocity of a particle is known with 100% certainty, then the position should be 100% uncertain, no?


No, the uncertainty principle relates position to momentum, not its speed. You don't know their momentum because it goes to infinity as the speed approaches c. Anyway, how do you propose to measure the momentum of a particle which is now at the edge of the observable universe, light from it won't get here for billions of years?
MrVibrating
2.3 / 5 (3) Sep 16, 2012
Wrong way round, photons have no mass because the don't interact with the Higgs field the way other particles do.

Exactly what i said!

The source term in GR is the stress/energy tensor. Gravity is created by energy and pressure. Mass is merely a bound form of energy.

Yes but it is mass that causes spacetime curvature, not energy per se, and not EM radiation! You're misinterpreting their equivalence in the same way as Benni..

A box full of photons with a perfectly mirrored interior has greater mass than the same box without the photons even though each photon has no mass. Mass is m^2 = E^2 - |p|^2 For one photon E=|p| so m=0 For a box of photons the momenta partly cancel but the energies sum so m>0.

Now you're ascribing mass as an aggragate property of photons, and/or total internal reflection...! If the mass of each photon is zero then so is their net mass! Or else why not lose the box and just claim that a photon has non-zero energy and thus non-zero mass?
MrVibrating
3 / 5 (4) Sep 16, 2012
Equivalence tells us the energy value of mass, but it's one or the other, not both at the same time!

It's more complex. We know photons carry momentum, they push solar sails.


You're thinking of the ion wind. In principle radiation pressure sailing is possible, if seriously impractical.

We know they are deflected by gravitational lensing, hence for example if the Sun deflects a photon, it changes its momentum. If momentum is conserved, the Sun must have its motion changed to the photon has a gravitational effect on the Sun.
Photons follow straight paths through spacetime - lensing is caused by spacetime curvature.. ie. the photon doesn't alter course, spacetime itself does. Gravity is an interaction between things with rest mass!
MrVibrating
2.3 / 5 (3) Sep 16, 2012
However, according to GR, photons do not interact with each other so parallel beams do not converge. Note this has nothing to do with "relativistic mass" which is another topic entirley (and one of the least helpful concepts ever invented IMHO).
But if they had non-zero mass, they would interact with eachother; the reason they don't is because they're integer-spin bosons with no mass. Gravitation via relativistic mass (radiation pressure) was invoked by Benni (and then, by yourself with the mirror box example) - i'm refuting it. Why do you believe relativistic mass is an unhelpful concept when it's an incontrovertible consequence of equivalence? It's the force that keeps stars like our Sun inflated - we wouldn't be here without it! I'll agree it's a common source of misgivings though.. (ahem)
ValeriaT
2.3 / 5 (3) Sep 16, 2012
why do you believe relativistic mass is an unhelpful concept when it's an incontrovertible consequence of equivalence
I presume it's because he feels, that the massive photon concept violates the general relativity in its very consequences. In general relativity the massive objects cannot spread with speed of light, so if photons would be massive, they couldn't move with speed of light anymore. On the contrary, if they would be massless, then the stars couldn't lose their mass through radiation - which apparently violates the observations as well...

My theory has no problem with it, because IMO photons don't move with speed of light - but with lower one into account of their stability. But relativity has no defense against such an argumentation.
kevinrtrs
1.8 / 5 (5) Sep 16, 2012
So they're saying that the power of darkness exists and is fully operational today?
Mike_Massen
2.3 / 5 (6) Sep 16, 2012
kevinrtrs needs to learn how to address his comments, ie To who
So they're saying that the power of darkness exists and is fully operational today?
Might be time for you to go back to bed unless you can drop your religious bias, no matter how subtle you think it is. I've seen you on several discussions, eventually you throw in tangential aspects from the bible. Don't you get it yet ! Your deity is a really bad communicator - all from "Voices in the Head" of insecure people with big ego's...
wkrasl
5 / 5 (2) Sep 16, 2012
@adrianv, wkrasl,

The universe has been expanding all the while the most ancient of the photons have been traveling toward us.

...

But maybe you can see how the actual distance to the observable horizon is much greater today than just c*T (where T is the age of the universe.)


Pink ... No argument. I agree with you.

I am simply confused by the claim that the universe today has a radius of 46B light years according to the figure. Isn't the universe 13.7B years old? Doesn't this mean that the universe had to expand more than 3 times the speed of light???

I'm not even saying that this is wrong. I'm just asking for clarity. For example, I understand the initial inflationary period was very short and that THAT period was faster than light. So is my confusion over how FAR that initial inflation expanded the universe? Did the initial FTL expansion expand the universe to 30B light years radius -- with all subsequent expansion then slower than light to 46B today?
wkrasl
not rated yet Sep 16, 2012
... oops ... I meant the distance of a semicircle following the surface, so that would be only r * pi, so the point singularity of the big bang would now be 46B times pi light years away.

Yes, I am thinking of a 4D sphere with space being a 3D expanding surface. Thanks for allowing the analogy. :)

What you are not figuring is that there was this magical period right after the BB in which the universe was able to expand at a million(?) times the speed of light. That is the reason given as to why we observe a flat universe today.


P2 ... Thank you. That is exactly what I think might unconfuse me. Yours is the first post that suggested the initial FTL expansion might be millions of times c. I never knew that!

So, help me out. That initial expansion resulted in what radius? I expect it went to something less than 46B-13.7B; i.e. 32.3B light years or more.

But assuming roughly uniform expansion, isn't 2/3 of the universe then more than 13.7B LY away?
antialias_physorg
5 / 5 (1) Sep 16, 2012
Isn't the universe 13.7B years old? Doesn't this mean that the universe had to expand more than 3 times the speed of light???

No. It means that you do not understand the difference between an explosion 8which expands at the front) and an inflation (which expands at every point in the volume)

Also there is no (known) limit to the speed at which space can inflate. the speed of light is not applicable as a speed limit.

So, help me out. That initial expansion resulted in what radius?

To the size of about 10cm accross. Which still means 100 doublings of size from the initial state.

But assuming roughly uniform expansion, isn't 2/3 of the universe then more than 13.7B LY away?

'Currently'? Yes. But simultaneity is tricky in an expanding universe. If the universe stopped expanding 'now' then a photon emitted 'now' there would travel 46bn years to get to us (but with expansion continuing/accelerating it may be much longer or it may even neve reach us c.f. the big rip)
MrVibrating
2.7 / 5 (3) Sep 16, 2012
why do you believe relativistic mass is an unhelpful concept when it's an incontrovertible consequence of equivalence
I presume it's because he feels, that the massive photon concept violates the general relativity in its very consequences. In general relativity the massive objects cannot spread with speed of light, so if photons would be massive, they couldn't move with speed of light anymore. On the contrary, if they would be massless, then the stars couldn't lose their mass through radiation - which apparently violates the observations as well...
Relativistic mass is not a rest mass though, it's an effective mass due to imparted momentum as a photon interacts with matter, an inescapable consequence of mass/energy equivalence!
My theory has no problem with it, because IMO photons don't move with speed of light - but with lower one into account of their stability. But relativity has no defense against such an argumentation.
Yet we don't see photons gravitate!
MrVibrating
1 / 5 (1) Sep 16, 2012
@Fleetfoot

For a box of photons the momenta partly cancel


..and sorry but are you suggesting such a box would have a non-zero momentum? In what direction?

A photon box with total internal reflectivity experiences equal radiation pressure in all directions. Proof of Roger Shawyer's EM drive notwithstanding...
wkrasl
not rated yet Sep 16, 2012
Okay, I'm working on understanding http://en.wikiped...nflation right now.

I appreciate all the responses to my earlier posts. Thanks.
Shinichi D_
1 / 5 (1) Sep 16, 2012
So they're saying that the power of darkness exists and is fully operational today?


Yes. Just look at yourself.
Shinichi D_
1 / 5 (1) Sep 16, 2012

I am simply confused by the claim that the universe today has a radius of 46B light years according to the figure. Isn't the universe 13.7B years old? Doesn't this mean that the universe had to expand more than 3 times the speed of light???


The observable universe has a radius of 46B ly. The 'whole' universe could very well be billion and billion times bigger. There is no known edge to it, neither 13,7B ly nor 46B ly avay. So there is no fixed speed to expansion. The speed of expansion depending on how far two points are from each other.
Fleetfoot
5 / 5 (1) Sep 16, 2012
I am simply confused by the claim that the universe today has a radius of 46B light years according to the figure. Isn't the universe 13.7B years old? Doesn't this mean that the universe had to expand more than 3 times the speed of light??? .. I'm just asking for clarity.


The most distant material from which we see light is the plasma that emitted what we now receive as the CMBR. Its redshift is 1089 which means the universe has expanded by a factor of 1090 since then. It was emitted when the universe was roughly 378 thousand years old. At that time, the material was 41 million light years from us so it is now 42 billion light years away.

The distance between us and the source material was increasing at about 50 times the speed of light (which only limits how fast material can travel through space). This diagram in Ned Wright's excellent tutorial shows the distance (horizontal) to the light versus cosmic age (vertical):

http://www.astro....htm#mstd
Fleetfoot
5 / 5 (3) Sep 17, 2012
Wrong way round, photons have no mass because the don't interact with the Higgs field the way other particles do.

Exactly what i said!


The way you wrote it seemed to swap cause and effect but it's a minor point.

Yes but it is mass that causes spacetime curvature, not energy per se, and not EM radiation! You're misinterpreting their equivalence in the same way as Benni..


It was mass in Newton's Law but not in GR, here is the equation:

http://en.wikiped...cal_form

Note that all the terms relate to energy and momentum while mass per se doesn't appear at all. It enters the equation only via the equivalence equation.
Fleetfoot
5 / 5 (1) Sep 17, 2012
Equivalence tells us the energy value of mass, but it's one or the other, not both at the same time!


If you think of a hydrogen atom as an electron orbiting a proton, you can say the electron has kinetic energy due to its motion and potential energy due to the electric charges, but both of those are subsumed into the mass of the hydrogen atom. That part is both energy and mass depending on your point of view.
Fleetfoot
5 / 5 (4) Sep 17, 2012
It's more complex. We know photons carry momentum, they push solar sails.


You're thinking of the ion wind. In principle radiation pressure sailing is possible, if seriously impractical.


The Ikaros sail is currently cruising round the Solar System:

http://en.wikiped...i/IKAROS

It uses LCD panels whose reflectance can be altered for attitude control, ions would be stopped by them at all times.

In fact the pressure due to the ions of the Solar wind is about 1000 times less than the radiation pressure of the photons.
Fleetfoot
5 / 5 (1) Sep 17, 2012
Why do you believe relativistic mass is an unhelpful concept when it's an incontrovertible consequence of equivalence? .. I'll agree it's a common source of misgivings though.. (ahem)


A simple example, I have a brick on scales in front of me. The scales read 1kg for its mass. From the point of view of someone walking past, the mass is greater than 1kg.

Objects have a different mass depending on the coordinate system which is counter intuitive if you intend "mass" to be a measure of the amount of material in an object.

Mathematically, mass is invariant in relativity and IMHO the best understanding is provided by realising that it is the magnitude of the energy-momentum 4-vector. It is then characteristic of the object regardless of the observer's choice of coordinate system.
Fleetfoot
5 / 5 (2) Sep 17, 2012
Okay, I'm working on understanding http://en.wikiped...nflation right now.

I appreciate all the responses to my earlier posts. Thanks.


Note that inflation occurred in the first 10^-32s or less, what we can see is limited to the period after 378,000 years later so inflation isn't really relevant to your question.
Fleetfoot
not rated yet Sep 17, 2012
A box full of photons with a perfectly mirrored interior has greater mass than the same box without the photons even though each photon has no mass. Mass is m^2 = E^2 - |p|^2 For one photon E=|p| so m=0 For a box of photons the momenta partly cancel but the energies sum so m>0.


..and sorry but are you suggesting such a box would have a non-zero momentum? In what direction?


In the direction the box is moving ;-)
In the rest frame of the box, they cancel exactly of course.

Now you're ascribing mass as an aggragate property of photons, ...! If the mass of each photon is zero then so is their net mass!


Draw a graph with momentum horizontal and energy vertically upwards. A single photon moving left to right looks like this

/

Since E=|p|, m=0.

One moving right to left is

\

and again m=0

Add them together and you get

\
/

The vector sum is

|\
|/

Now p=0 but the energies add so m=2E.

This is all standard relativity, check a text book if you doubt me.
DarkHorse66
3.3 / 5 (3) Sep 17, 2012
"A simple example, I have a brick on scales in front of me. The scales read 1kg for its mass. From the point of view of someone walking past, the mass is greater than 1kg."

Don't mean to be disparaging, but that is a badly worded and confusing(especially to those who don't understand the difference)example. You don't appear to be distinguishing between mass and weight. You can't weigh mass per se. If you are using scales, then you are measuring how much the mass of an object is being influenced by the gravity it is interacting with.
W = m * g Assuming that we are assuming earth gravity, and taking 'g' to be roughly equal to 9.81 N/kg, the mass of your 1kg object will be roughly equal to 0.1019kg, or about 102grams. If however, you did mean mass, then THAT would be equal to 9.81kg. But scales aren't designed to measure mass directly...
It might be worthwhile rewording that example for the general sake of clarity. :)
Best Regards, DH66
Fleetfoot
5 / 5 (3) Sep 17, 2012
"A simple example, I have a brick on scales in front of me. The scales read 1kg for its mass. From the point of view of someone walking past, the mass is greater than 1kg."

Don't mean to be disparaging, but ...


No problem, you are quite right of course.

Assuming that we are assuming earth gravity, and taking 'g' to be roughly equal to 9.81 N/kg, the mass of your 1kg object will be roughly equal to 0.1019kg, or about 102grams. If however, you did mean mass, then THAT would be equal to 9.81kg. But scales aren't designed to measure mass directly...
It might be worthwhile rewording that example for the general sake of clarity. :)
Best Regards, DH66


Try this:

A mass of 1kg on the scales produce a downward force of 9.81N due to gravity. The calibration of the scales displays this as the equivalent mass by assuming the value of 'g'.

The key point remains that relativistic mass is different depending on the motion of the observer.
Urgelt
not rated yet Sep 17, 2012
So... the researchers found a correlation in measurement data which suggests a repulsive effect of some kind. What kind, nobody knows. It could be an actual kind of energy, or it could be something heretofor overlooked in gravitational theory.

What the researchers are saying is that the effect is real. They are saying nothing about what causes the effect. We still have no internally-consistent, testable theory explaining why the effect manifests in measurement data.

I think we should rename 'dark energy' to 'unexplained cosmological effect (UCE).' Then the media and amateur commenters will be less eager to pretend that they know what the heck is causing it.
Shinichi D_
not rated yet Sep 17, 2012

I think we should rename 'dark energy' to 'unexplained cosmological effect (UCE).' Then the media and amateur commenters will be less eager to pretend that they know what the heck is causing it.


Doesn't matter. It wouldn't help trolls. And we understand so or so.
Benni
1 / 5 (8) Sep 17, 2012
What the researchers are saying is that the effect is real. They are saying nothing about what causes the effect. We still have no internally-consistent, testable theory explaining why the effect manifests in measurement data.


And if they really had any concept at all of what they are talking about that these things are proven, then they should be able to tell us what frequency of EM to look at, but they don't.

I think we should rename 'dark energy' to 'unexplained cosmological effect (UCE).' Then the media and amateur commenters will be less eager to pretend that they know what the heck is causing it.


If they are unable to point to the frequency of EM, you are exactly right. I get the impression many posters think there is energy out there so mysterious that it is not electro-magnetism, they don't understand if it is not EM, then it is not energy.

Fleetfoot
5 / 5 (3) Sep 17, 2012
And if they really had any concept at all of what they are talking about that these things are proven, then they should be able to tell us what frequency of EM to look at, but they don't.


It is not EM, definitely. It is accurately described by the Cosmological Constant in Einstein's field equations but some physicists consider that to be something that should lie on the curvature side of the equation, that is it is an inherent part of the geometry rather than a separate form of "energy". See for example:

http://arxiv.org/...02.3966/
Mike_Massen
2 / 5 (4) Sep 17, 2012
Fleetfoot offered
Yes, the early universe was radiation-dominated so it is a standard part of the standard solution to the Friedmann Equations to include the gravitational effect of photons.
Sorry I didnt make myself clearer, I was getting at the wake a photon produces in space-time in the *current* universe and cumulative effects thereof ?
Fleetfoot continued re photon's IRF in transit
Correct... because it is of zero length and duration. Any tutorial on relativity should cover that
My exposure to Relativity was in 1979, 2nd year uni as part of electronic engineering so we didnt go into that detail which interestingly touches on philosophy. I guess zero length arises from the limit of Lorentz contraction but, in the current maths/physics how does the 1/0 result from the use of the Lorentz factor become zero duration. ie. I reasoned it might but, I cant see the conventional maths of my time in the late 1970's reaching that postulate with some definitive arithmetic rationale ?
Fleetfoot
5 / 5 (1) Sep 17, 2012
I was getting at the wake a photon produces in space-time in the *current* universe and cumulative effects thereof ?


I know, what I was saying was that you are right but the effect of a single photon is so small it is of no significance. Even the sum total of all the photons from the Big Bang was only significant for the first ~50,000 years after which matter dominated, for the next 6 billion years.

I cant see the conventional maths of my time in the late 1970's reaching that postulate with some definitive arithmetic see the conventional maths of my time in the late 1970's reaching that postulate with some definitive arithmetic rationale?


Lorentz contraction is useful for a phenomenological approach but you should have covered the concept of proper time (usually denoted by tau) as distinct from coordinate time as well. The proper time for a photon from emission to absorbtion is zero:

http://en.wikiped...lativity
cantdrive85
1.8 / 5 (5) Sep 17, 2012
Blah, blah, blah. Nothing but mental masturbation with no hope for climax, or copulation for that matter.
Fleetfoot
5 / 5 (1) Sep 17, 2012
I just noticed a bit got lost from a previous post:

.. it is mass that causes spacetime curvature, not energy per se ..


It was mass in Newton's Law but not in GR, here is the equation:

http://en.wikiped...cal_form


The curvature is on the left hand side, what cause it is on the right hand side. That is the stress-energy tensor:

http://en.wikiped...y_tensor

Note that all the terms relate to energy and momentum while mass per se doesn't appear at all. It enters the equation only via the equivalence equation.


Note also, the cosmological constant can be placed on the right side where it plays the part of "dark energy" rather than being part of the geometry:

http://en.wikiped...constant

Obviously, that is still a matter of some debate and study ;-)
Mike_Massen
3.3 / 5 (7) Sep 17, 2012
cantdrive85 blurted out of impatience and boredom from an anti-intellectual position nodoubt
Blah, blah, blah. Nothing but mental masturbation with no hope for climax, or copulation for that matter.
In other words "Education", try to get a grip, your 'climax' is a life-long process, enjoy it while you can before your local entropy reaches its inevitable asymptote ;-)
Next time, might I suggest, like all mature contributors, offer something useful by way of convergence in respect of rationale to arrive at an inalienable truth...

Benni
1 / 5 (3) Sep 17, 2012
And if they really had any concept at all of what they are talking about that these things are proven, then they should be able to tell us what frequency of EM to look at, but they don't.


It is not EM, definitely. It is accurately described by the Cosmological Constant in Einstein's field equations but some physicists consider that to be something that should lie on the curvature side of the equation, that is it is an inherent part of the geometry rather than a separate form of "energy".


I already understand that it is not EM (energy), but the entire discussion to this point, including the article, is that there is this mysterious non-EM energy, which is a contradiction of terms. I don't think even you are comprehending where I'm going with this.I don't know how many different ways I can say the same thing, if it is not EM (photons), it is not energy, call it something else, but leave the word "energy" out of it. Is that more clear?
Fleetfoot
not rated yet Sep 17, 2012
I already understand that it is not EM (energy), but the entire discussion to this point, including the article, is that there is this mysterious non-EM energy, which is a contradiction of terms. I don't think even you are comprehending where I'm going with this. I don't know how many different ways I can say the same thing, if it is not EM (photons), it is not energy, call it something else, but leave the word "energy" out of it. Is that more clear?


It was quite clear the previous times and also quite obviously wrong. EM is only one form of energy, there are others. For example tie a brick to a string and wind it round the rotor of a generator. Let the brick fall and the generator produces power. Where did that energy come from? From the gravitational potential energy of the brick. That is also not EM. The generator turns the energy from potential to electrical forms.

Do you think it makes sense to ask on what frequency you would find gravitational potential energy?
Benni
2.3 / 5 (3) Sep 17, 2012
....there is this mysterious non-EM energy, which is a contradiction of terms. I don't think even you are comprehending where I'm going with this. I don't know how many different ways I can say the same thing, if it is not EM (photons), it is not energy, call it something else, but leave the word "energy" out of it.


It was quite clear the previous times and also quite obviously wrong. EM is only one form of energy, there are others. For example tie a brick to a string and wind it round the rotor of a generator. Let the brick fall and the generator produces power. Where did that energy come from? From the gravitational potential energy of the brick. That is also not EM. The generator turns the energy from potential to electrical forms.

Do you think it makes sense to ask on what frequency you would find gravitational potential energy?


No because "potential" has no spectroscopy. Show me a spectroscopy of your "potential energy".
Mike_Massen
1 / 5 (2) Sep 18, 2012
@Fleetfoot
Thanks re Proper time, maths confirm asymmetrical SR
ie. accelerated R.Frame but disturbs some on other threads sure SR is perception & unreal. Evidence via GPS, accelerated radioactive atoms, Hafele_Keating etc & others, Tah :-)

Re Dark Energy, any consensus in respect of combinatorial Permutations, Eg.

- No more inflation or some
- No. of planck spacetime units increasing or not
- Other structural change in spacetime

Where's research focus going to address above permutations ?

Re Earlier query re wake of photons, what is your opinion of an experiment Eg.

- long vacuum tube chilled close to zero K
- surrounded along its length by bolometers
- tube dia larger than beam divergence
- laser varying freq & intensity along length

Could we observe, short or long term:-
- bolometers registering anything whether laser on/off
- accumulate particles in tube eg. result from Virtual Particle Collisions
- other effect

Prior experiments offering info re related issues?
Shinichi D_
3 / 5 (2) Sep 18, 2012


No because "potential" has no spectroscopy. Show me a spectroscopy of your "potential energy".


Yes, exactly. That's what we are talking about. :)
Fleetfoot
not rated yet Sep 18, 2012
Do you think it makes sense to ask on what frequency you would find gravitational potential energy?


No because "potential" has no spectroscopy. Show me a spectroscopy of your "potential energy".


Exactly, it is a form of energy other than EM.
Benni
1 / 5 (5) Sep 18, 2012
Do you think it makes sense to ask on what frequency you would find gravitational potential energy?


No because "potential" has no spectroscopy. Show me a spectroscopy of your "potential energy".


Exactly, it is a form of energy other than EM.


And you don't know what "spectroscopy", I do, I work with with it as part of my job description. Spectroscopy is part of what I do in our lab, usually gamma ray regions of interest.

You were doing OK for so long as you could hold onto that "perfect mirror box", after that you lost it my friend. With the "mirror box" you appeared to show some gravitas of reason, that when photons exit a body of defined mass, the mass becomes lighter, the reason of course being that the photons carry away mass as mass is transformed to energy. This is the spectroscopy I do almost everyday in our lab.

I've requested to see spectroscopy of your definition of energy, and you have not been up to that challenge.
vidyunmaya
1 / 5 (4) Sep 18, 2012
Sub: Cosmic Function of the Universe
The Cosmic Function of the Universe is distinct- Index to prime concepts- Cosmology Vedas .Need orientation to new concepts.
http://www.scribd...Dec-1999
http://vidyardhic...pot.com/
Fleetfoot
3 / 5 (2) Sep 18, 2012
Do you think it makes sense to ask on what frequency you would find gravitational potential energy?


No because "potential" has no spectroscopy. Show me a spectroscopy of your "potential energy".


Exactly, it is a form of energy other than EM.


And you don't know what "spectroscopy", I do, I work with with it as part of my job description. Spectroscopy is part of what I do in our lab, usually gamma ray regions of interest.


I work in electronics, specifically communications. We use Fast Fourier Transforms which are the RF equivalent of spectroscopy, it is part of what I do every day too.

The point is that the brick hanging from a string before it falls has potential energy, but that energy is NOT in the form of EM.
Benni
1 / 5 (2) Sep 19, 2012
The point is that the brick hanging from a string before it falls has potential energy, but that energy is NOT in the form of EM.


If the world tried to function with your form of "energy", "work" could never be accomplished. You still don't understand where I'm going with this do you?
Benni
1 / 5 (2) Sep 19, 2012
The point is that the brick hanging from a string before it falls has potential energy, but that energy is NOT in the form of EM.

Rather than to continue leaving you hanging Fleet: Everything in the Universe that has mass has the "potential for energy", but high physics books misnomer this "potential energy".
Meyer
5 / 5 (3) Sep 19, 2012
I don't know how many different ways I can say the same thing, if it is not EM (photons), it is not energy, call it something else, but leave the word "energy" out of it. Is that more clear?

You're the one trying to redefine "energy". Maybe you should come up with a new term for the specific form that energy takes when a force is mediated by photons. You could call it, hmm I don't know, electromagnetic energy?
Fleetfoot
not rated yet Sep 19, 2012
The point is that the brick hanging from a string before it falls has potential energy, but that energy is NOT in the form of EM.


If the world tried to function with your form of "energy", "work" could never be accomplished.


It's not "my" form, it is that of Newton and it is the form that is used when we say "energy is conserved". If you want to discard the Principia and everything since, you've got a lot of work to redo. In the example I gave, the energy stored by the brick results in "work being done" on the load attached to the generator. Connect a resistor and its temperature rises as the brick falls.

You still don't understand where I'm going with this do you?


Until you correct your understanding of the concept of energy, it is academic where you imagine you are going.
siouxdax
1 / 5 (1) Sep 24, 2012
Typo! In the first paragraph regarding WMAP, it should be 4.6 billion light years away, NOT 46 billion. And kids say punctuation is pointless (no pun intended).

Fleetfoot
5 / 5 (2) Sep 26, 2012
Typo! In the first paragraph regarding WMAP, it should be 4.6 billion light years away, NOT 46 billion. And kids say punctuation is pointless (no pun intended).


The paragraph is correct, it should read 46 billion. The redshift of the CMBR is 1089 so the ratio of distance at time of emission to that now is 1090. The figures are approximately 42 million light years then and 46 billion light years now.

More news stories

Easter morning delivery for space station

Space station astronauts got a special Easter treat: a cargo ship full of supplies. The shipment arrived Sunday morning via the SpaceX company's Dragon cargo capsule.