Astrophysicists spy ultra-distant galaxy amidst cosmic 'dark ages'

Sep 19, 2012
In the big image at left, the many galaxies of a massive cluster called MACS J1149+2223 dominate the scene. Gravitational lensing by the giant cluster brightened the light from the newfound galaxy, known as MACS 1149-JD, some 15 times. At upper right, a partial zoom-in shows MACS 1149-JD in more detail, and a deeper zoom appears to the lower right. Credit: NASA/ESA/STScI/JHU

With the combined power of NASA's Spitzer and Hubble space telescopes as well as a cosmic magnification effect, a team of astronomers led by Wei Zheng of The Johns Hopkins University has spotted what could be the most distant galaxy ever detected.

Light from the young galaxy captured by the orbiting observatories shone forth when the 13.7-billion-year-old was just 500 million years old.

The far-off galaxy existed within an important era when the universe began to transit from the so-called "Dark Ages." During this period, the universe went from a dark, starless expanse to a recognizable cosmos full of . The discovery of the faint, small galaxy accordingly opens up a window into the deepest, remotest epochs of .

"This galaxy is the most we have ever observed with high confidence," said Zheng, a principal research scientist in The Henry A. Rowland Department of Physics and Astronomy at Johns Hopkins' Krieger School of Arts and Sciences and lead author of a paper appearing in Nature on Sept. 20. "Future work involving this galaxy—as well as others like it that we hope to find—will allow us to study the universe's earliest objects and how the Dark Ages ended."

Light from the primordial galaxy traveled approximately 13.2 billion light-years before reaching NASA's telescopes. In other words, the starlight snagged by Spitzer and Hubble left the galaxy when the universe was just 3.6 percent of its present age. Technically speaking, the galaxy has a , or "z," of 9.6. The term "redshift" refers to how much an object's light has shifted into longer wavelengths as a result of the . Astronomers use "redshift" to describe cosmic distances.

Unlike previous detections of galaxy candidates in this age range, which were only glimpsed in a single color, or waveband, this newfound galaxy has been seen in five different wavebands. As part of the Cluster Lensing and Supernova Survey with Hubble program (CLASH), the Hubble Space Telescope registered the newly described far-flung galaxy in four bands. Spitzer located it in a fifth band with its Infrared Array Camera (IRAC), placing the discovery on firmer ground.

Objects at these extreme distances are mostly beyond the detection sensitivity of today's largest telescopes. To catch sight of these early, distant galaxies, astronomers rely on "gravitational lensing." In this phenomenon—predicted by Albert Einstein a century ago—the gravity of foreground objects warps and magnifies the light from background objects. A massive galaxy cluster situated between our galaxy and the early galaxy magnified the latter's light, brightening the remote object some 15 times and bringing it into view.

Based on the Spitzer and Hubble observations, astronomers think the distant galaxy was spied at a time when it was less than 200 million years old. It also is small and compact, containing only about 1 percent of the Milky Way's mass. According to leading cosmological theories, the first galaxies should indeed have started out tiny. They then progressively merged, eventually accumulating into the sizable galaxies of the more modern universe.

These first galaxies likely played the dominant role in the epoch of reionization, the event that signaled the demise of the universe's . About 400,000 years after the Big Bang, neutral hydrogen gas formed from cooling particles. The first luminous stars and their host galaxies, however, did not emerge until a few hundred million years later. The energy released by these earliest galaxies is thought to have caused the neutral hydrogen strewn throughout the universe to ionize, or lose an electron, the state in which the gas has remained since that time.

"In essence, during the epoch of reionization, the lights came on in the universe," said paper co-author Leonidas Moustakas, a research scientist at NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif.

Astronomers plan to study the rise of the first stars and galaxies and the epoch of reionization with the successor to both Spitzer and Hubble—NASA's James Webb Telescope, slated for launch in 2018. The newly described will likely be a prime target.

Holland Ford, one of Zheng's colleagues and a co-author on the paper, commented on the findings.

"Science is very exciting when we explore the frontiers of knowledge," said Ford, a physics and astronomy professor at Johns Hopkins. "One of these frontiers is the first few hundred million years after the birth of our universe. Dr. Zheng's many years of searching for quasars and galaxies in the dawn of the universe has paid off with his discovery of a galaxy that we see as it was when the universe was less than 500 million years old.

"With his discovery, we are seeing a galaxy when it was not even a toddler," Ford said. "But this infant galaxy will in its future grow to be a galaxy like our own, hopefully hosting planetary systems with astronomers who will look back in time and see our galaxy in its infancy."

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yyz
4.4 / 5 (7) Sep 19, 2012
The letter in Nature (with illustrations, but still behind a paywall) can be found here: http://www.nature...446.html

This system was already found to have the largest gravitationally-lensed images of any strongly lensing galaxy cluster: http://arxiv.org/abs/0906.5079

Hopefully the full paper will be posted on arXiv soon.
SteveL
4.2 / 5 (6) Sep 19, 2012
I don't care that it's old tech. The Hubble is still an awesome bit of engineering and is still an incredibly valuable and powerful tool for science.

On the other hand, how a galaxy can actually be an actual complete galaxy within 200 million years the creation of the universe, well incredulity is my strongest response. Even though it's a very small galaxy, something doesn't seem to add up. 200 million years is not much time for a galaxy to assemble.
Psiotic
3.7 / 5 (6) Sep 19, 2012
I'm wholeheartedly awaiting the day that 'they' find a system that blows their age/timeline of things completely out of the water. (Find a system that's much older than the big bang)
vidyunmaya
1.1 / 5 (9) Sep 19, 2012
Sub: Identity Crisis
Information:suggesting that they may be the dominant source for the early re-ionization of the intergalactic medium.[ref.Nature]
NEED: Source- Fields-flows- Spread functional Index
Many thanks to http://arxiv.org/...79v2.pdf
see Inputs: Cosmology vedas Interlinks
Vidyardhi Nanduri
VendicarD
2.3 / 5 (6) Sep 20, 2012
How do they know that this galaxy is just not red faced and embarrassed for being so close and so oddly shaped?

Has anyone thought of asking it?

Stupid Scientist people.

theon
1.8 / 5 (12) Sep 20, 2012
We have to come to terms with the inconvenient truth that observations show once again that galaxies did not form late, but early, by fragmentation instead of accretion. And that reionization, not needed in that picture, did just not happen. That WIMP dark matter does not exist, since it would create a mess at the galactic scale. To me it looks a lot like religion: We do not look "blindly" at the facts, we look at them within our anticipation from the standard theory, even if it fails over and over again. Like today. And, I bet, tomorrow. Cosmology has to move into cosmonomy, like astrology moved into astronomy.
hcnap
3 / 5 (2) Sep 20, 2012
Amazing stuff. Are we getting closer to the edge of the universe? What could possibly be beyond the edge? Is it theoretically possible?
antialias_physorg
5 / 5 (5) Sep 20, 2012
We have to come to terms with the inconvenient truth

I never really underrstand this: What exactly is 'incovenient' about findings that don't fit with the predictions?
That's what science is (to a scientists) all about, and why it's so much fun to do.
PinkElephant
5 / 5 (7) Sep 20, 2012
@SteveL,
Even though it's a very small galaxy, something doesn't seem to add up. 200 million years is not much time for a galaxy to assemble.
How so?

200 million years is quite a long time. Several (on the order of 10) generations of blue giant stars can come and go over such a span of time.

Early universe was much denser, suffused with stronger electric currents and magnetic fields, thermal turbulence, and megastar winds and explosions. Things may as well have happened faster in such a dynamic environment, compared to the more stabilized and sparse universe of the later epochs.
theon
3.4 / 5 (5) Sep 20, 2012
We have to come to terms with the inconvenient truth

I never really underrstand this: What exactly is 'incovenient' about findings that don't fit with the predictions?
That's what science is (to a scientists) all about, and why it's so much fun to do.


You may read Popper about paradigm shifts, or just look in the papers, reports and blogs to see how little attention is payed to the possibility that the standard paradigm is just wrong.
PinkElephant
3.5 / 5 (2) Sep 20, 2012
@theon,
...astronomers think the distant galaxy was spied at a time when it was less than 200 million years old. It also is small and compact, containing only about 1 percent of the Milky Way's mass. According to leading cosmological theories, the first galaxies should indeed have started out tiny. They then progressively merged, eventually accumulating into the sizable galaxies of the more modern universe.
Please explain how the above direct quote (from the above article) stands in contradiction to the "standard paradigm".
antialias_physorg
4.6 / 5 (7) Sep 20, 2012
200 million years is not much time for a galaxy to assemble

In the early universe stuff was a lot closer together. With lots of mass close together stellar formation is much more rapid and you get much more massive stars (up to 150 solar masses until the radiation push is too strong for additional mass to fall in)

Bigger stars burn hotter and consequently go through their supply of fuel much faster. This means that they had lifetimes on the order of merely a few million years before going boom - sending out a shockwave that could compact nearby gas into potentially new stellar nurseries.

antialias_physorg
5 / 5 (7) Sep 20, 2012

You may read Popper about paradigm shifts, or just look in the papers, reports and blogs to see how little attention is payed to the possibility that the standard paradigm is just wrong.

We know it is wrong. Every theory (if you want to be pedantic) has to be wrong to some degree. They are models. Every model is an approximation of the reality it models. In the act of approximation you ALWAYS introduce an error. The often quoted saying is "the map is not the territory"

HOWEVER: That the standard theory is not (and cannot) be ultimately correct doesn't mean we should ditch it UNLESS a better theory is out there.
Better meaning: one that can explain all past observations AND make better predictions about future obsrvations than the standard model does. And curently there is none out there that fits the bill.

Eventually one will be found and then that will become the standard model.
antialias_physorg
5 / 5 (10) Sep 20, 2012
Especially when it provides jobs and salaries for physicists involved, isn't it true?

You really are clueless about the scientific world, aren't you?

Scientists are smart, highly educated people with a plethora of skillsets (at least all the ones I've ever met and worked with).
You know the number of applications I had to write after my PhD to get a job that pays triple what I earned before (after taxes)? One. And I'd say I was an averagely skilled researcher.

If you think ANY scientist is in science for the money or the job security then you need a reality check, fast.

Why so suddenly? Even before three years you haven't said so and you were a firm supporter of Standard model.

You misunderstand. I still support the standard model as the best one out there. But I ALSO understand that ANY model CANNOT be ultimately correct by the simple fact that it is a model.

Science isn't about truth. It's about what works. The standard model currently works best.
PinkElephant
4.6 / 5 (11) Sep 20, 2012
If we realize, that the universe was already expanded to its (nearly) final size and density
At 300 million years, the universe was less than 12% its current radius (meaning less than 0.2% its current volume and hence, more than 500x its current density.)
under these condition such a well developed galaxy has absolutely no chance to be formed, because the matter was very hot and diluted this time.
First, it's hardly "well-developed", at merely 1% of Milky Way's mass. Secondly, by 300 million years the universe was no longer "very hot". Nor, as already mentioned, was it particularly diluted.
condensation of stars from the interstellar gas inside of galaxies effectively stops at much higher density, than the average density of matter in the primordial Universe
We're talking about condensation of galaxies, which requires much lower densities still (most of the stars begin to form after the proto-galaxy has already taken shape).
SteveL
3 / 5 (2) Sep 20, 2012
Early universe was much denser, suffused with stronger electric currents and magnetic fields, thermal turbulence, and megastar winds and explosions. Things may as well have happened faster in such a dynamic environment, compared to the more stabilized and sparse universe of the later epochs.
This is kind of exactly my point. There is so much chaos and turbulence, so how do masses grow under such conditions? From a purely mechanical standpoint every time I stur something (introduce chaos) it's to mix it up, not let it congeal. Yet under chaotic conditions the opposite is true for not just stellar, but a galactic formation where star clusters are grouped around centralized masses?
It still seems to me that 200 million years is far too short a time for developing such order in conditions of such chaos. Unless of course mechanisims are in place that I haven't read about or seen discussed. Admittedly, I cannot deny the possibility, but presently I'm still doubtful.
antialias_physorg
4.4 / 5 (7) Sep 20, 2012
There is so much chaos and turbulence, so how do masses grow under such conditions?

Gravity.

That people talk of 'turbulence' and 'chaos' doesn't mean we're talking hurricanes and densities compared to Earth's atmosphere. Just a lot more dynamic and dense than the current situation in outer space.

The current situation is about 1-10 hydrogen atom per cubic meter on average in the universe. Back then we're talking about a volume 500 times smaller. So on average that's 500 to 5000 atoms per cubic meter.

For comparison: The best man-made vacuum in a vacuum chamber (classified as an ultra high vacuum) still contains 10 million MOLECULES (not just atoms) per cubic meter.
Fleetfoot
5 / 5 (4) Sep 20, 2012
most of the stars begin to form after the proto-galaxy has already taken shape
But we already see the distant galaxy glowing.


That's why it's called a "proto-galaxy".

by 300 million years the universe was no longer "very hot".
The dark era period was recently moved to 250 - 750 megayears after Big bang


Those numbers don't appear in the article you quote.

It does say "Sometime between 100 and 500 million years after the big bang, one of these little clumps became dense enough to form the first star ..". Models from a few years ago suggested 130 million, more recent models handling dark matter more accurately suggest it was nearer 30 million years.

Either way, the temperature had fallen below 3000K by 400 thousand years so it was not hot when the first stars formed, far less by the time of this observation.
brodix
2.3 / 5 (3) Sep 20, 2012
According to inflation theory, the inflation stage is responsible for the "flatness" issue, which means it blew the initial universe up so large initially, that it appears flat and our visible universe is only a small fraction, so it would seem that after the inflation stage, it really wasn't as dense as it would seem to need to be, to grow a galaxy in 200 million years.
How is it that space can be said to expand, yet there is still a constant speed of light, against which to measure it? What provides that stable frame, if it isn't space?
Pressure2
2.3 / 5 (3) Sep 20, 2012
When we view this galaxy now we are seeing the universe as it was 13.2 billion years ago with a radius of 13.2 billion light years. Remember all that we see at these distances happened after the inflationary period. Even then it doesn't appear to be dense and conducive to galaxy and star formation. So time could certainly be a problem.
antialias_physorg
1 / 5 (1) Sep 20, 2012
was 13.2 billion years ago with a radius of 13.2 billion light years.

No and no.

1) Objects closer to us we see from times not quite so long ago. The image of proxima centauri we get is merely 4 years old. Only the cosmic microwave background (and some of the very early stars/galaxies) is light from that era.

2) How do you connect 13.2bn year old light toi a radius of 13.2bn lightyears. that doesn't make any sense at all. Especially since you reference yourself the early inflationary period.
Pressure2
3 / 5 (4) Sep 20, 2012
AP: The galaxy referred to in this article was where we view it 13.2 years ago in a universe with a diameter of at least 26.4 billion light years. Sure everything else we see is in a lesser time period. How do I connect 13.2 billion light year to a radius of 13.2 billion years, well it took that light from that galaxy 13.2 billion years to get here, that is the radius of the universe at that time 13.2 billion years ago.
PinkElephant
5 / 5 (3) Sep 20, 2012
@SteveL,
From a purely mechanical standpoint every time I stur something (introduce chaos) it's to mix it up, not let it congeal. Yet under chaotic conditions the opposite is true for not just stellar, but a galactic formation where star clusters are grouped around centralized masses?
You are using bad analogies. When you stir something, there are (typically) no intrinsic forces trying too clump it; the stirred condition is actually preferred (usually) as a more thermodynamically stable (higher-entropy) state. By stirring, you are merely accelerating (or catalyzing) what will happen through natural Brownian motion eventually, anyway. With galaxy formation, you have the opposite: diffuse gas and dust is a dynamically unstable system that *wants* to collapse gravitationally. Give it a nudge, and it's more than happy to begin clumping together.
PinkElephant
5 / 5 (1) Sep 20, 2012
@natello,
The average density of matter was still fifteen(!) orders bellow density of interstellar gas inside of galaxies.
But the density was not uniform (see CMB), so it's meaningless to talk of averages. Point being, there was much more matter readily available to flow into the nascent gravitational wells and accrete around the first black holes.

Really, primordial galaxies form quite nicely and early in computer simulations that put all the relevant physics into effect; there are no major issues there at all. As mentioned in the above article, the discovery of this galaxy was actually expected, and many more like it are expected to be found in the future (especially when the James Webb begins operating), perfectly in accordance with the standard cosmological model.
Fleetfoot
4.2 / 5 (5) Sep 20, 2012
AP: The galaxy referred to in this article was where we view it 13.2 years ago in a universe with a diameter of at least 26.4 billion light years. Sure everything else we see is in a lesser time period. How do I connect 13.2 billion light year to a radius of 13.2 billion years, well it took that light from that galaxy 13.2 billion years to get here, that is the radius of the universe at that time 13.2 billion years ago.


The redshift is 9.61 so the galaxy was 2.96 billion light years away when the light was emitted. That distance was increasing by 1% every 7.7 million years hence it took the light 13.25 billion years to reach us. The galaxy is now 31.4 billion light years away.

http://www.einste...2010.htm
Pressure2
2 / 5 (4) Sep 20, 2012
Fleetfoot: There is a problem with the figures you gave. If the galaxy we observe at 13.2 billion lightyears was only 2.96 billion lightyears from us when the light was emitted we would have to be at the very center of the universe. The reason is because every direction we look the universe looks the same, it is flat. If we are not in the center it would look different in different directions.
Pressure2
2 / 5 (4) Sep 20, 2012
Let see, the universe is 13.7 billion years old and we can see at least 13.2 billion lightyears into the past. And the universe still appears the same in every direction. So that only leaves 500 million years where a difference could appear in some directions. Darn, it appears we are in the center of the universe AGAIN.
PinkElephant
4.3 / 5 (6) Sep 20, 2012
@Pressure2,
The reason is because every direction we look the universe looks the same, it is flat. If we are not in the center it would look different in different directions.
The universe has no center. No matter where you are within it, it will look flat in all directions all the way out to 13.7 billion years.

Do not confuse the observable universe horizon (defined by the age of universe and light speed) with actual size of the universe. The universe itself has no defined size (in standard cosmology); it is infinite in extent. At any point in that infinite continuum, you would currently be able to see for 13.7 billion years in all directions, and it would look just as flat in all directions.

The expansion of the universe does not proceed from any center or any single point. Spacetime is expanding at EVERY point, simultaneously, uniformly.
Psiotic
1.6 / 5 (7) Sep 21, 2012
Until mainstream/orthodox scholars can set aside the 'classic' views of things (theory of relativity/gravity is king), we're going to be like flies after the light on the opposite side of the glass. We've become far to reliant/dependant/formed on traditional rules and it has crippled our logic, as well as our imagination.

Our greatest achievements were covered in ridicule and abandonment. Those lone rangers of yesteryears are far less and few today because the ego has become more important that the research.
antialias_physorg
not rated yet Sep 21, 2012
Those lone rangers of yesteryears are far less and few today because the ego has become more important that the research.

You cleraly have never been in research or even talked to any researcher. Stop pulling stuff out of your behind.
Pressure2
2.3 / 5 (3) Sep 21, 2012
Notice the excerpt below avoids stating the size of the universe after the inflationary period. They realize if they state the universe is below the visible horizon it would place us in the center.

"This horizon describes the visible universe—a region some 28 billion light years in diameter. But what are the horizons of a civilization that inhabits the most distant galaxies we see? And what about galaxies at the limits of their vision? There is every reason to think that the universe extends a long way beyond the part of the universe we can see. In fact, a variety of observations suggest that our visible patch may be a small fraction—maybe an infinitely small fraction—of the whole universe."

http://www.pbs.or...rse.html
Pressure2
2.3 / 5 (3) Sep 21, 2012
Notice in the excerpt below from Wiki, they also avoid stating a size that is below the visible universe. In particular read the last sentence! They avoid the center of the universe trap by stating the universe could be infinite.

" According to general relativity, space can expand faster than the speed of light, although we can view only a small portion of the universe due to the limitation imposed by light speed. Since we cannot observe space beyond the limitations of light (or any electromagnetic radiation), it is uncertain whether the size of the universe is finite or infinite."

http://en.wikiped...Universe
Pressure2
1 / 5 (2) Sep 21, 2012
PE: You give a very good description of the universe. An it explains exactly why the inflationary period had to have expanded the universe beyond our sight horizon of 13 plus billion lightyears maybe infinitely. You put it in better words than I could have, thanks.
Pressure2
3 / 5 (4) Sep 21, 2012
PE: I don't want you to get the idea that I agree with your explanation of the modification of the inflationary modification of the Big Bang theory. My compliment was that you explained the most recent theory explaining the origin of the universe that avoids the center of the universe trap very well. The reason I don't accept it is because the current BB theory has had to resort to Harry Potter type magic and breaks a known law of physics, the speed of light.
Pressure2
2.3 / 5 (3) Sep 21, 2012
Believe me I already know your response, it doesn't break the speed of light because it is the space between the light waves and between matter that is expanding. Like I said magic. How come we seem unable to detect space expanding between the stars in our galaxy or our galaxy and nearby galaxies.
Space could also be view for what it is nothing. It is only the interaction between matter and energy that gives space a dimension.
Fleetfoot
4 / 5 (4) Sep 21, 2012
you explained the most recent theory ...


The basic model hasn't changed since it was proposed by Friedmann in 1922, hardly the "most recent".

The reason I don't accept it is because the current BB theory has had to resort to Harry Potter type magic and breaks a known law of physics, the speed of light.


Not true, the "known law" is general relativity and the Friedmann Equations were derived as a solution to GR. The problem is that the popular press/layman version doesn't deal with the real physics but tries to explain it in simple language which loses significant detail in some cases. The rule is that the maximum speed that can be measured LOCALLY is the value 'c'. That means that light in a distant galaxy passes the last asteroid when leaving at that speed as measured from the asteroid, not anywhere else. That's the rule, and it isn't broken, no magic needed.
Fleetfoot
5 / 5 (1) Sep 21, 2012
.. explaining the origin of the universe that avoids the center of the universe trap ..


Actually, there are two possibilities for the model, one finite and the other infinite in spatial extent but neither of them has a centre. The finite version is like the old "Asteroids" arcade game, there is a finite area to the screen but going off one side brings objects back on the opposite side. The finite universe is the same wrap-round model, just in 3D.

The dividing line is like "escape velocity", fire a bullet upwards from a moon and if it is moving fast enough it travels to infinity, slowing to some positive terminal speed. Too slow and it reaches a finite height then falls back. The boundary between the cases is when the speed is exactly equal to escape velocity and in that case it still goes to infinity but the terminal speed is zero. In cosmology, a flat universe is that boundary case and WMAP says it is within 0.5% of being flat.
Fleetfoot
4.2 / 5 (5) Sep 21, 2012
The universe itself has no defined size (in standard cosmology); it is infinite in extent.
Unfortunately it cannot be, if the dark era had begun just at the Universe event horizon - if it would be infinite, then there would be any indicia of Universe transform, formation the less at the event horizon.


There is such an indication, the CMBR produced when the universe was uniformly filled with hot plasma very similar to the surface of the Sun.

This is just one of conceptual problems of Big Bang cosmology.


It's not a problem at all, in reality it is strong evidence in favour of the model. The older alternatives like steady state have no credible explanation for its existence or spectrum.
Pressure2
3.5 / 5 (2) Sep 21, 2012
Fleetfoot: An the present BB model has no credible explanation as to why the universe is flat. Futhermore the BB model has evolved several time over the last half century. The inflationary period was not part of the original BB theory. The inflationary period has been modified several times also. It was only introduced after it became apparent that the universe was flat and without an inflationary period we were placed in the center of the universe. The inflationary period was a fairly recent ad hoc add on.
antialias_physorg
1 / 5 (1) Sep 21, 2012
The reason I don't accept it is because the current BB theory has had to resort to Harry Potter type magic and breaks a known law of physics, the speed of light.

Whoa. Hold on a second. I think you have some very basic misunderstandings about the BB and the standard model. The speed of light (limit) for particles (and light) isn't broken anywhere in the BB.
Pressure2
1 / 5 (1) Sep 21, 2012
AP: It is by the magic of expanding the space between the light waves and particles of matter.

Fleetfoot: The inflationary period was not added to the BB theory until some time after 1980. The accelerating expansion has become another ad hoc add on much more recently.

"The term "inflation" is also used to refer to the hypothesis that inflation occurred, to the theory of inflation, or to the inflationary epoch. The inflationary hypothesis was originally proposed in 1980 by American physicist Alan Guth, who named it "inflation".[2] It was also proposed by Katsuhiko Sato in 1981."[3]

http://en.wikiped...smology)
antialias_physorg
not rated yet Sep 21, 2012
It is by the magic of expanding the space between the light waves and particles of matter.

What's so magical about that?

http://en.wikiped...evidence
SteveL
not rated yet Sep 21, 2012
antialis and PinkElephant - thanks for the explanations. They helped.
SteveL
1 / 5 (1) Sep 21, 2012
Philosophically we may as well be in the middle of the universe, after we are at the center of everything that will ever effect us in any way. Realistically though, due to inflation I'd expect the center of the universe, if there is such a thing, to be a thin area or a baryonic void.
Fleetfoot
5 / 5 (2) Sep 21, 2012
Fleetfoot: An the present BB model has no credible explanation as to why the universe is flat.


The Hamiltonian (total energy) of a closed universe can be shown to be zero because the gravitational potential energy (negative) cancels the positive radiation and matter density, hence the universe is flat because the energy density exactly matches the critical value. That's not proven but WMAP says the value is within 0.5% of critical so it looks likely.
Fleetfoot
5 / 5 (3) Sep 21, 2012
The inflationary period was not added to the BB theory until some time after 1980.


Agreed but inflation is still just a driver that altered the rate of expansion, it still only affects the rate of change of the scale factor a(t) in the basic model which is still given by the Friedmann Equations.

The accelerating expansion has become another ad hoc add on much more recently.


Einstein included the cosmological constant in GR, it is not a recent addition. Nor is it ad hoc, the value has only recently been measured.
PinkElephant
5 / 5 (1) Sep 21, 2012
@Pressure2,
it explains exactly why the inflationary period had to have expanded the universe beyond our sight horizon of 13 plus billion lightyears maybe infinitely
No, that's incorrect. Let's forget for now about the infinite extent of the spacetime continuum, and focus on the currently observable portion that is a sphere with a radius of 46 billion light-years, centered on us. At the instant of the Big Bang, this entire sphere was compressed to a vanishingly small point. At the end of the inflationary epoch, this entire sphere had a radius of just a few centimeters. Subsequent expansion into its present size, occurred under more "normal" conditions, without strong contribution from the inflaton field.

The key is that such inflation and subsequent expansion occurred at every point of the pre-BB manifold (which was presumably also infinite in extent.)
PinkElephant
3.5 / 5 (2) Sep 21, 2012
ctd.

The main reason inflation was incorporated into the standard model of cosmology, was not to explain the size or rate of expansion of either spacetime or the observable horizon. Rather, its purpose was to explain why matter seems to be distributed through the universe as uniformly as it is, because under the orthodox model the clumping of matter should have been a lot more severe due to gravitational interactions that amplify quantum-scale fluctuations early in the Big Bang. The superluminal inflation period prevents such interactions, and smears out the severe fluctuations of the primordial quantum foam, thus leading to a much more uniform distribution of matter across the universe, as is observed. There was also a problem with primordial exotic particles that are not observed to exist; inflation solves the problem by preventing such particles from forming in the first place.
ValeriaT
1 / 5 (3) Sep 21, 2012
At the instant of the Big Bang, this entire sphere was compressed to a vanishingly small point. At the end of the inflationary epoch, this entire sphere had a radius of just a few centimeters

This violates all claims, that the Universe is infinite in accordance of Big Bang cosmology. Actually because the factor of inflation is known in this theory (1:10E40), the diameter of the whole Universe doesn't differ very much from observable Universe diameter very much (90 GLyrs = 10E40 x 2 cm).

This example just illustrates, how confused the proponents of Big Bang model actually are: they cannot see the simple connections across pile of their math (which works well at isolated particular cases being fitted to them with its parameters - but in global sense it just violates logics)...

This case is nothing new for me, the Ptolemy model, general relativity and/or quantum mechanics do behave in the same way: their logics violates their own formal predictions.
PinkElephant
3.5 / 5 (2) Sep 21, 2012
the space between the light waves and between matter that is expanding.
Not really 'between', so much as 'across'. It is the ongoing expansion of space even as light travels through it, that causes the light's wavelength to grow over time (this is the reason for the cosmological redshift.) The expansion of space literally stretches or smears out each photon individually (as well as increasing the intervals between consecutive photons, of course.) Space also expands both between and inside particles of matter, but the size of matter particles is constrained by their structure and the various fields and forces that define them, so they re-constrict around that expanding space and maintain constant size. These compensatory mechanisms are of course limited by light speed, so they will continue to operate unless space begins to expand too rapidly for them to be able to compensate (as would happen in the final stages of the hypothetical "Big Rip".)
ValeriaT
1 / 5 (2) Sep 21, 2012
The ignorance of logical flaws of Standard cosmology model has the same socioeconomical roots like the ignorance of heliocentric model in Galilei era or the ignorance of cold fusion: at the moment, when some model generates the isolated quantitative predictions, which enable to publish horoscopes or to pile-up publications, then there is no economical or psychological motivation to judge it in wider context. The community of scientists cannot judge the logical flaws of their model from outside until their money are going: they've no tools for it.
ValeriaT
1 / 5 (2) Sep 21, 2012
These compensatory mechanisms are of course limited by light speed, so they will continue to operate unless space begins to expand too rapidly for them to be able to compensate (as would happen in the final stages of the hypothetical "Big Rip".)
Such a "Big Rip" should actually happen not only at distant future, but at the surface of event horizon of observable Universe, when the speed of alleged omnidirectional expansion of space-time should exceed the speed of light. At the particle horizon the particle of matter should be ripped of in the same way, like the particles at distant future. The diameter of particle horizon is estimated to 16 billions of light years. In my model it actually happens, because the distant future is actually observable at the quantum scale - all particles appear disintegrated at the Higgs scale.
PinkElephant
4.3 / 5 (3) Sep 21, 2012
we seem unable to detect space expanding between the stars in our galaxy or our galaxy and nearby galaxies
We can't detect the expansion within our galaxy, because currently space is expanding too slowly for that. However, we CAN detect expansion of space between galaxies. The current rate of expansion (i.e. the Hubble Constant), or in other words the quantity of new space added per unit of time over a given stretch of space, is about 70 km per second per megaparsec. In other words, across every 1 million light-years of space, every second approximately an additional 21 kilometers of extra space emerges. This is quite small: the diameter of the Milky Way is about 100,000 light years, meaning our galaxy's diameter should be expanding by a mere 2.1 km per second. Compare this to the distance between Earth and the Sun (vanishingly minuscule on the galactic scale) -- 149,597,871 km. It'd take our galaxy 2.25 years just to grow by 1 measly AU (8.31 light-minutes).
Pressure2
1 / 5 (2) Sep 21, 2012
Fleetfoot: I'm not sure you even understand what is meant by a flat universe, I doubt that PE does either. It means that all the light we observe in the universe today arrives from every direction to us in straight lines. This could not happen unless the distant galaxies we observe expanded straight away from us leaving us at the center of the universe. Nobody liked that so the inflationary period was added in order for the light from the earliest galaxies and the CMBR to arrive to us in the straight lines we observe today. This is why they had to be in the positions we view them at today shortly AFTER the inflationary period some 13.7 billion year ago.

Both of you need to go back and reread the two earlier posts that stated the size of the universe is unknow and may even be infinite. The 13.7 billion light years radius is just the minimum size after the inflationary period. Geez, it may have even been infinite!
ValeriaT
1 / 5 (2) Sep 21, 2012
We can't detect the expansion within our galaxy, because currently space is expanding too slowly for that
The true is, we don't observe any shrinking of the space between galaxies in older areas of Universe - the Universe appears pretty homogeneous there. And of course, we don't observe any expansion of galaxies itself neither. In reality the distant galaxies appear larger in average, which would indicate, they do actually shrink with age instead. This indeed falsifies the Big Bang cosmology on behalf of Steady state model too.

The supporters of Standard model cosmology are claiming, maybe this model is wrong (Alphanumeric), but we need more experiments and observations to prove it. But this is just a employment driven lie, because both the logical, both the observational flaws of Standard Model are known for years. But the inertia of mainstream prohibits in change of paradigm because of crowds of scientists siting on pile of equations
PinkElephant
3.5 / 5 (2) Sep 21, 2012
It means that all the light we observe in the universe today arrives from every direction to us in straight lines.
No. When cosmologists discuss "flatness", they are talking about a FOUR-dimensional surface being flat (that is, they are talking about space-time, not just space.) When restricting discussion to just space, flatness means that space continues to expand indefinitely, but at an ever-decreasing rate, so that at an infinite future its expansion rate is 0. A non-flat spacetime ends either in a Big Rip or a Big Crunch.

Regardless of whether spacetime is in fact flat or not, light rays from distant sources will always travel along apparently straight lines within space, because the expansion of space is uniform in all directions (so, it does not bend the light rays.)
ValeriaT
1 / 5 (2) Sep 21, 2012
I'm pretty sure, these discussions will continue with every galaxy found deeper and deeper in the Universe. The MACS 1149-JD galaxy violates the Standard model already, because it sits at the area of Universe, which should be covered with reionization. Actually no reionization did happen there, just the image of distant galaxies becomes blurred with CMBR fluctuations. This indeed complicates the direct evidence of Steady state cosmology, but we have another indirect evidence for it in the radiowaves spectrum already. The particle model of the Universe predicts, for these long wavelengths the red shift should be replaced with blue shift and with positive violations of inverse square law, which would make the distant sources of radiowaves blueshifted and brighter, than it corresponds their distance. And this is what was already observed - these observations were just ignored, because they weren't recognized in their context.
PinkElephant
not rated yet Sep 21, 2012
Just to clarify: inflation and flatness of spacetime are two independent issues. Spacetime could easily be flat in absence of inflation, and it can easily be non-flat in presence of inflation, and vice versa. These are independent mechanisms and dynamics, and they're governed by (apparently) independent parameters.
ValeriaT
1 / 5 (1) Sep 21, 2012
light rays from distant sources will always travel along apparently straight lines within space, because the expansion of space is uniform in all directions
But is it really so? The homogeneity of light spreading is already violated with dark energy (the spreading of light appears slower at distant past) and with so-called dark flow. And of course every dark matter violates the homogeneity of light spreading too, the mainstream physics is just not calling it so. So far, when some violation of Lorentz symmetry has been found, it was always attributed to some additional field for not to threat the basic postulates of relativity. It's an analogy of adding epicycles into Ptolemy model for the sake of its saving against new experimental facts. Even in AWT certain motivation for keeping of Lorentz symmetry exists - but from conceptual point of view nothing prohibits us to consider every lensing as a flagrant violation of special relativity.
Pressure2
1 / 5 (1) Sep 21, 2012
PE quote: "At the end of the inflationary epoch, this entire sphere had a radius of just a few centimeters." another quote, "Rather, its purpose was to explain why matter seems to be distributed through the universe as uniformly as it is,"

Well if the universe at the end of the inflationary period was only a "few centimenter" it would NOT explain the "uniform distribution" you state was needed any better than the BB itself.

No, the main unspoken reason for the inflationary period was to "move us" out from the center of a flat universe.

PinkElephant
not rated yet Sep 21, 2012
it would NOT explain the "uniform distribution" you state was needed
Oh, but it does. Unfortunately, here is where mere vernacular stops being sufficient, and the only way to prove the point is to go into the hard math.
No, the main unspoken reason for the inflationary period was to "move us" out from the center of a flat universe.
Absolutely wrong, and I see you still don't understand what it means for the universe to be flat.

Maybe you're confused by spacetime curvature due to gravity, where a common visualization is a rubber sheet with a depression in it and spacetime is said to be curved, whereas absent the depression spacetime is said to be flat. That is all fine and good, but the sort of "flatness" we talk about in that case, is NOT the same kind of "flatness" we talk about when discussing cosmology. Try to re-read what I posted above regarding what it means for spacetime to be flat in the context of cosmology.
ValeriaT
1 / 5 (1) Sep 21, 2012
the main unspoken reason for the inflationary period was to "move us" out from the center of a flat universe ...Absolutely wrong, and I see you still don't understand what it means for the universe to be flat.
It's not wrong, it's just a little schematic. The main problem of Big Bang cosmology was, it leads into inhomogeneous i.e. non flat Universe - and the inflation was proposed just to solve this problem. After all, one of main inhomogeneity of Big Bang model expected would be just the radial gradient of this explosion.

In my experience, when someone suddenly doubts the qualification of opponent, it's just indicia, he just did run out of arguments. Try to exhibit more empathy into alternative ways of thinking and you'll see, this opinion was actually quite substantiated - you just were unprepared for it.
ValeriaT
1 / 5 (1) Sep 21, 2012
If you would follow the water surface analogies of the space-time, red shift and universe expansion, then you would realize, that steady state model provides very similar predictions, like the Big Bang cosmology in certain scope of distance and mass/energy density scales. It just differs at the boundary of visibility scope of the observable Universe, which we are starting to analyze right now. Actually I don't support neither Big Bang, neither Steady State model - the random Universe model requires/expects the mixture of both models. The violation of Steady state model comes just from the side, which supports the original Big Bang cosmology with its center of expansion, i.e. without its later additions like the dark matter, energy and inflation. It's the Doppler's anisotropy of CMBR, which actually violates both inflationary cosmology, both Steady state cosmology and turns us back into Big bang model.
PinkElephant
5 / 5 (1) Sep 21, 2012
after all, one of main inhomogeneity of Big Bang model expected would be just the radial gradient of this explosion.
Big Bang is not an explosion. It is an expansion.

Perhaps another analogy will help. Ignoring the dynamism of the universe, imagine for a moment that the universe is an infinite static 2D bitmap of infinitely fine resolution. Spacetime expansion is then equivalent to a zoom-in operation on that bitmap. When we zoom into the bitmap, all features on the bitmap simultaneously get larger on-screen, and the on-screen distances between all of them simultaneously increase in all directions, while the geometric relationships (angles, proportions) between them stay the same. There is no "center" to this expansion. And it's not any sort of an "explosion".
ValeriaT
1 / 5 (1) Sep 21, 2012
Big Bang is not an explosion. It is an expansion. There is no "center" to this expansion.
It was just you, who claimed above, that the original Universe was a pin-point singularity and/or 2 cm sphere in diameter, which just expanded in fracture of second in its current size (you're just confusing the state before and after inflation - the 2 cm sphere is the size of the alleged original singularity itself).

If such an expansion is not an explosion, then I really don't understand, which type of explosives are you routinely dealing with, what makes such a difference for you and which testable predictions such a difference provides.
PinkElephant
4.5 / 5 (2) Sep 21, 2012
It was just you, who claimed above, that the original Universe was a pin-point singularity and/or 2 cm sphere in diameter
Again, you are confusing the OBSERVABLE universe (which is a sphere with us at its center), vs. the ENTIRE universe (which is infinite in extent, and which contains our currently-observable sphere.) The ~10 (not 2) cm sphere I was talking about, was the post-inflation size of the currently-observable sub-volume of the universe, not of the ENTIRE universe.
ValeriaT
1 / 5 (2) Sep 21, 2012
Why not to face the reality: the Big Bang model is logically fringe model which enables the quantitative predictions with using of pile of constant fitted to the observations? It has some merit from conceptual point of view, if we accept the idea, that the Universe itself is steady state but highly dynamic and random stuff, so that the density gradient penetrating the whole observable range of Universe appears like the Big Bang observed from side. Laura Mersini believes, the whole Universe is large quantum wave traveling from place to place. Another idea (both relevant as fringe) is that the Universe is large expanding black hole, we are sitting at its surface and the CMBR dipole anisotropy is just the surface gradient of this black hole. And so on - you can actually design infinitely many models from random reality in similar way, like we can see many shapes inside of random clouds on the summer sky. Each such perspective would be relevant in some aspect, fringe in another ones.
ValeriaT
1 / 5 (2) Sep 21, 2012
The ~10 (not 2) cm sphere I was talking about, was the post-inflation size of the currently-observable sub-volume of the universe, not of the ENTIRE universe
I see - and the initial pin-point singularity - which you talked about in the same post - is supposed to be the observable Universe, or the entire Universe? If its observable Universe only (as it would follow from the context of this post) - what are we talking here actually, when talking about Big Bang, if not about the explosion of observable Universe inside of some hypothetical, steady state infinite Universe? Actually it's all one big logical nonsense - the only logically consistent model of Big bang is the emergent scattering of ripples at the water surface: this scattering would appear from perspective of surface ripples just like the expansion of that surface without apparent center. Every other physical model known to me will just lead into some conceptual confusion soon or later.
PinkElephant
5 / 5 (1) Sep 21, 2012
I see - and the initial pin-point singularity - which you talked about in the same post - is supposed to be the observable Universe, or the entire Universe?
Depending on your favorite mathematical interpretation of singularities, it could be either.

Personally, I don't believe in actual singularities (e.g. truly infinite densities); if I'm right then assuming that the universe is infinite in extent now, then it follows that it was also infinite in extent prior to the Big Bang (in which case, that "pin-point singularity" would correspond to the observable universe embedded in a pre-Big Bang, ultra-high-density manifold of infinite extent.)

On the other hand, if you believe in infinite densities, then you could say that the entirety of the currently-infinite universe was compressed to a single point. But I dislike that notion, because it fails to conserve information, and really does appear to create something from nothing.
PinkElephant
5 / 5 (1) Sep 21, 2012
If its observable Universe only (as it would follow from the context of this post) - what are we talking here actually, when talking about Big Bang, if not about the explosion of observable Universe inside of some hypothetical, steady state infinite Universe?
We'd be talking about a uniform expansion of a formerly highly-compressed manifold of infinite extent, of which the observable universe was (and still is) but an infinitesimal sub-volume.
ValeriaT
1 / 5 (2) Sep 21, 2012
Depending on your favorite mathematical interpretation of singularities, it could be either.
I hope, you're realizing, that the model which doesn't distinguish the observable portion of Universe from Universe itself from its very beginning cannot lead into any logically consistent predictions later. The steady state infinite large Universe cannot be considered as the pin-point exploding singularity at the same moment...;-)

And we still don't ask, what actually exploded, the reasons from which it had exploded - but not enough - and why it inflated just a bit later - but not enough - and why it expanded with increased speed later. Whole this model appears as ad-hoced, fabricated and fitted to the observations, as possible.

The silly Ptolemy model or even the God's creation appears more physically relevant than that. Until we realize, that the obsolete particle model of Universe could solve whole this controversy.
Pressure2
1 / 5 (2) Sep 21, 2012
PE: Can you explain how the universe can be much larger than the visible universe now if the inflationary period stopped at a few centimenters? Your information is off by a factor of at least 13.7 billion lightyears.

"WMAP has confirmed this result with very high accuracy and precision. We now know that the universe is flat with only a 0.5% margin of error. This suggests that the Universe is infinite in extent; however, since the Universe has a finite age, we can only observe a finite volume of the Universe. All we can truly conclude is that the Universe is much larger than the volume we can directly observe."
http://map.gsfc.n...ape.html
ValeriaT
1 / 5 (1) Sep 21, 2012
BTW the notion of pin-point singularity and infinite extension of it at the same moment is nothing new in contemporary physics. It has it's counterpart in so-called the complementarity of black holes. These theoretical artifacts can be described as differently from intrinsic and extrinsic perspective as the initial Universe in Big Bang model. This complementarity naturaly arises from water surface model of space-time too: at the proximity there is always big difference between description of water surface from perspective of transverse and longitudinal waves of it. But at the boundary of the visibility scope both kind of waves scatter mutually, so these two perspective become indistinguishable. We can see, that this model can explain both Big bang, both Steady state cosmologies, both their controversies at the same moment. The same applies for another ad-hoced concepts, like the inflation, red shift and dark energy.
PinkElephant
5 / 5 (3) Sep 21, 2012
the model which doesn't distinguish the observable portion of Universe from Universe itself from its very beginning cannot lead into any logically consistent predictions later
That's the problem with singularities in general. All math and logic breaks down at a singularity, which is one reason I personally don't believe singularities in fact exist in reality (but rather, IMHO, are an artifact of incomplete mathematical models.)
The steady state infinite large Universe cannot be considered as the pin-point exploding singularity at the same moment
I haven't said anything about any sort of steady state. Indeed, expansion of a formerly-compressed Universe is kind of an opposite of a steady-state. (And I will continue to insist on correcting your terminology: Big Bang is not an explosion, and was never formulated as an explosion. Big Bang is an expansion -- omnidirectional stretching -- of a four-dimensional manifold of infinite extent.)
ValeriaT
1 / 5 (2) Sep 21, 2012
All we can truly conclude is that the Universe is much larger than the volume we can directly observe."
Well, this is just the problem - the flatter and larger the Universe appears, the less probable becomes the option, it was spatially limited singularity before limited time. Of course, I didn't miss the fact, with improving technology the Standard model cosmology is forced to converge back to the Steady state model. Now the proponents of Big Bang model even are trying to pretend, that notion of infinite Universe was here from its very beginning, which is of course demagogic lie and it contradicts the concept of Universe beginning by its very definition. The infinite space-time implies infinite time, i.e. age of the Universe too - or the Universe cannot be not formed with space-time at all.
PinkElephant
4.5 / 5 (2) Sep 21, 2012
Can you explain how the universe can be much larger than the visible universe now if the inflationary period stopped at a few centimenters?
Again, the few centimeters post-inflation refers to the size of the currently-observable spherical volume (i.e. what you call "the visible universe"), which continued to expand after the period of rapid inflation ended, and which by now has expanded to 46 billion light years in radius.

Since we do not know of any boundaries to spacetime (and it almost seems silly to ask, where the universe ends, and what's beyond that), we assume that spacetime stretches out infinitely in all directions. We assume that we do not occupy any special or privileged location within that infinite expanse.

ctd.
ValeriaT
1 / 5 (1) Sep 21, 2012
All math and logic breaks down at a singularity, which is one reason I personally don't believe singularities
Not all - the logics of emergent particle model survives the singularity concept, although it's singular by itself - or rather because of it. You can really describe the singularity just with scattering of ripples inside of particle environment without problem - and you can even draw picture of it. During such scattering the wavelength of transverse waves expands into wavelength of longitudinal waves and vice-versa: from this perspective the singularity is not a pin-point object, but a gradualist topological inversion of space-time: the time dimension becomes spatial one and vice-versa. Best of all, this topological craziness occurs at small scale during each spreading of common ripples at the water surface.
PinkElephant
5 / 5 (1) Sep 21, 2012
To see how the observable universe fits into that bigger picture, just mentally run the Big Bang backwards. Compress that infinite expanse (with our observable volume embedded in it), until our current 46 billion light year sphere is 10 cm across. The infinite expanse around this little ball of a sphere is still infinite (because you can't make an infinity finite simply by scaling it by some factor), but it is now at every point as incredibly dense and hot as that little 10-cm ball.
ValeriaT
1 / 5 (2) Sep 21, 2012
Since we do not know of any boundaries to spacetime (and it almost seems silly to ask, where the universe ends
No no no, my dear..;-) The infinite Universe concept has nothing to do with Big Bang cosmology from many reasons. Not only it contradicts the concept of the finite age of the universe, but it even insist on the idea, that the matter was formed just at its event horizon. If the Universe would be really of the unlimited size, then there would be no reason to expect the matter formation just at the visibility boundary of it. Such an infinite universe would simply appear like smooth surface of black hole swallowing all matter into itself - no dark era, no baryogenesis, no formation of galaxies should occur there. Literally speaking, it would appear like landscape covered with dark fog and the oldest galaxies would appear similarly to Milky Way. But the Big Bang cosmology puts the formation of galaxies just at the boundary of the visibility scope - and this is the problem.
PinkElephant
4.5 / 5 (2) Sep 21, 2012
The infinite Universe model has nothing to do in Big Bang cosmology from many reasons.
In fact, it is one of the basic assumptions in Big Bang cosmology.
Not only it contradicts the concept of the finite age of the universe
The "finite age" we measure refers only to the post-Big Bang elapsed time. Big Bang cosmology has nothing to say about what existed, or for how long, prior to the Big Bang (it's kind of analogous to distinction between the theory of evolution vs. the problem of abiogenesis.) That is in no small part due to lack of any (currently known) observable phenomena pre-dating the Big Bang.
If the Universe would be really of the unlimited size, the there would be no reason to expect the universe formation just at the visibility boundary of it.
Indeed, there's no reason. What we observe at the visibility boundary, was also happening 13.5 billion years ago right where we sit and everywhere else. By looking far away, we merely look back in time.
ValeriaT
1 / 5 (2) Sep 21, 2012
The concept of infinite universe is actually way closer to Steady State universe model phenomenologically: it may still consider, that the space-time is "somehow" expanding omnidirectionally - and at the moment, when the speed of this expansion will exceed the speed of light, then all objects will get red-shifted to CMBR wavelength so they will dissapear from out sight. Please note: not a single world about some condensation of galaxies from diluted matter, baryogenesis, dark era, reionization, inflation and similar ideas. These fairy tales would become actually quite redundant, if the Universe would be of infinite size - we couldn't observe them anyway.

These controversies could be quite easy to deduce even before eighty years, when the Big bang model was postulated - it's not true, we still have no experimental data for their judging. It's the widespread lie, the only motivation of which is to provide additional support of existing grants and social credits of people involved.
PinkElephant
4.8 / 5 (4) Sep 21, 2012
Once again, we are not at the center of anything, and there has not been any sort of an explosion. What we see 13.5 billion light-years away, is literally what happened there 13.5 billion years ago (because that's how long it took that light to reach us.) The same exact processes of galaxy formation and reionization were happening 13.5 billion years ago throughout the infinite universe, and thus throughout the observable volume as well (including right where we are currently located.) By now (that is, 13.5 billion years later), proto-galaxies such as MACS 1149-JD have accreted mass and merged with other proto-galaxies, and are mature grown galaxies just like the Milky Way. There is no "formation of galaxies just at the boundary of the visibility scope". Formation and evolution of galaxies occurred everywhere and throughout at the same time. Ditto for the dark era, reionization, etc.
ValeriaT
1 / 5 (2) Sep 21, 2012
In fact, it is one of the basic assumptions in Big Bang cosmology.
Nope - the basic assumption of Big Bang cosmology was the existence of primordial atom of very small size. Instead of it, so far the proponents of Big Bang cosmology claimed, every question about size of the space, in which such tiny thing could reside has absolute no meaning, because no such space was there: the Universe itself was such a tiny singularity..

The interpretation, that the infinitely large extension of the observable Universe has no meaning was quite widespread even before some ten - five years. It's not difficult to Google it. All right.. - but after then the idea, that the Big bang model somehow supports the concept of infinite universe has no merit. After all, just the fact, the Big Bang cosmology puts the beginning of matter formation just close to its origin demonstrates, that the concepts of observable universe and universe as such were freely interchangeable.
ValeriaT
1 / 5 (2) Sep 21, 2012
As another evidence of the finiteness of Universe in context of Big Bang cosmology may serve the concept of cyclic or bouncing universe. If the Universe would be really infinite, then it couldn't bounce from initial singularity and back into infinite size again in real time. This model is supposed to be an extension of the original Big Bang model and it couldn't work at all, if the Universe would be really infinite.

The whole problem is in neverending confusion of Big bang theory proponents in in their neverending mixing of intrinsic and extrinsic perspectives: the infinitely dense singularity may appear like infinitely large space from the perspective of the observer inside of it - but after then it cannot form the matter by its explosion. Instead of this, the observable matter would be formed with its shrinking and subsequent condensation inside it. Confusion and confusion...
PinkElephant
4.5 / 5 (2) Sep 21, 2012
Please note: not a single world about some condensation of galaxies from diluted matter, baryogenesis, dark era, reionization, inflation and similar ideas. These fairy tales would become actually quite redundant, if the Universe would be of infinite size - we couldn't observe them anyway.
The dark era and reionization are indirectly observable in bulk through measurements of the CMBR, and directly observable in detail with a sufficiently powerful telescope (and the James Webb is going to be just such a telescope.) Anything preceding reionization is indeed not observable, but can be deduced from the known laws of physics, distribution of matter across space, and observed cosmic element abundances.
the basic assumption of Big Bang cosmology was the existence of primordial atom of very small size
Again, this would refer to the pre-BB state of the observable volume, not the entire infinite universe stretching out in all directions beyond the current visibility horizon.
PinkElephant
5 / 5 (2) Sep 21, 2012
every question about size of the space, in which such tiny thing could reside has absolute no meaning, because no such space was there
That depends on what you mean by "size". Currently, we only know how to measure and define size using light or material objects like rulers, neither of which could exist in the primordial universe prior to BB. So in a strict mathematical sense, they are right: all known laws of physics and math break down in the pre-BB state, so it is "meaningless" to discuss properties and concepts that derive their definitions from the phenomenology of the post-BB spacetime. Besides, as previously mentioned, if you take the "tiny thing" to be actual singularity (of an exactly 0 volume), then all talk of measurements becomes meaningless. But I personally reject such fanatical absolutism (IMHO, reality takes precedence over math.)
Benni
1 / 5 (1) Sep 21, 2012
I've said it before & I'll say it again: With HUDF-JD2 sitting out there, a galaxy as big as Andromeda at 13.1 Gyr, I stopped being convinced years ago that the Universe is 13.66 Gyr old (going by the integral used in red-shift calculators).

Any of you posters who have yet to read about HUDF-JD2, plug it in to any search engine & get a real education about distant galaxy formation. Wait till they start finding a lot more of these galaxies, then watch the chaotic revisionism if it is discovered there are galaxies such as these on the other side of the so-called "primordial gas" cloud. There go all the red-shift calculators- Yeah Fleet, I tore that integral apart, it's one of the most concocted pieces of calculus I've ever come across.
ValeriaT
1 / 5 (2) Sep 21, 2012
The dark era and reionization are indirectly observable in bulk through measurements of the CMBR
The properties of which are derived from dark era and reionization... The age of universe is deduced from wavelength of CMBR expanding from original wavelength, the value of which is deduced from GUT (quantum mechanics) and ... from alleged age of the Universe. No, thank you - this is what the circular reasoning and epicycle model is called.

Just the recent observation of ultra-distant galaxy indicates, the universe is actually quite cool and transparent there and no condensation of matter had occured there. Everything else is just soothsaying from CMBR noise, the initial properties of which were adjusted to the same model originally.
PinkElephant
not rated yet Sep 21, 2012
just the fact, the Big Bang cosmology puts the beginning of matter formation just close to its origin demonstrates, that the concepts of observable universe and universe as such were freely interchangeable
There is no relationship between matter formation and extent of spacetime, and I don't see why you imagine there should be. Nor is there anything whatsoever at all in the mathematics of the Big Bang cosmology that would constrain the size of the universe beyond the current observational horizon. Indeed, the current observational horizon is not a fixed thing; the objects we can observe today used to be beyond the observational horizon in the past, and there are objects currently beyond that horizon today that will become visible in the future as their light begins to reach us.
an extension of the original Big Bang model and it couldn't work at all, if the Universe would be really infinite
Yes it can work, because infinite manifolds can still undergo contraction/expansion.
ValeriaT
1 / 5 (1) Sep 21, 2012
Yes it can work, because infinite manifolds can still undergo contraction/expansion.
Spatial manifold yes, but infinite space-time manifold is always of infinite age, or it's not space-time manifold (at least at its boundaries) anymore - but just spatial manifold only.
There is no relationship between matter formation and extent of spacetime
Of course it is - from Friedmann times - and it's called the critical density of the Universe. You should learn the Big Bang cosmology better - without it there would no reason for sudden formation of matter at the certain stage of the Universe expansion.
PinkElephant
not rated yet Sep 21, 2012
infinite space-time manifold is always of infinite age
That's right, and an infinite age (in an absolute sense) is exactly what is presumed by the cyclic/bouncing models you mentioned.
it's called the critical density of the Universe
Density is not the same thing as volume. An infinite volume can contain at every point a density of matter/energy valued at X. Stretch that infinite volume by a factor of 2 in all directions, now it has density X/8 at every point.
PinkElephant
5 / 5 (3) Sep 21, 2012
@Benni,
I'm not too concerned about HUDF-JD2. After all, according to the standard cosmological model the primordial galaxies formed around density inhomogeneities originating from the primordial quantum fluctuations present pre-inflation. The nature of quantum fluctuations is that they're random, meaning some will be small, most will fall within a certain range, and some will be extraordinarily large. So, I won't be surprised to see a few rare giant galaxies even early in the universe's history. Closer to home, we have giant ellipticals at the centers of galaxy clusters, with each such giant elliptical (e.g. IC 1101) containing mass on the order of 100x that of the Milky Way. One has to assume that in order to get so huge by now, these monstrosities probably also started out correspondingly bigger than most of the other galaxies. What matters, is the statistical distribution (rather than outliers) of galaxy sizes nearby vs. at visible boundary.
ValeriaT
1 / 5 (1) Sep 22, 2012
I won't be surprised to see a few rare giant galaxies even early in the universe's history
With new generation of infrared telescopes like the JWST we probably will see a crowds of galaxies in most distant areas of Universe. After all, we have first hints of these observations already... The smartness is not to change cosmological model when all observations are done already, but to anticipate them.
ValeriaT
1 / 5 (1) Sep 22, 2012
Some new speculations about real age of the Universe. The contemporary cosmologists aren't brave enough to throw out the concept of inflation completely, and they consider it ethernal or at least "past-ethernal" in context of the alleged multiverse. But we have apparent paradox here: for explanation of the homogeneity of the Universe at large scales we need the inflation working as well, as possible. On the other hand, the finding of very distant galaxies forces us to admit, that the inflation allowed quite large density fluctuations in primordial Universe, or we cannot explain these observations at all.
Pressure2
1 / 5 (2) Sep 22, 2012
This whole discussion here is really quite humorous. I mean when you resort to inflationary magic, why stop at a few centimeters, you might as well go for infinity. If I found a pot of gold at the end of a rainbow I wouldn't just take one or two coins, I'd take the whooole pot.
PinkElephant
5 / 5 (1) Sep 22, 2012
why stop at a few centimeters, you might as well go for infinity.
The choice is not arbitrary, it is dictated by constraints derived from observations of the universe's structure and matter content. Inflation expanded space at superluminal speeds, thus preventing adjacent points in space from "communicating" with each other (because communication is constrained by light speed.) Yet, for the largest currently-observed structures in the Universe to be able to form as early as they have, for the CMBR to reach a certain level of temperature equalization, and for there to be certain features present in the CMBR that indicate harmonic (acoustic) reverberations in the primordial matter, a certain level of information exchange between adjacent volumes in the early universe is necessary. These and other considerations put constraints on when inflation had to end. There are other constrains also, based on processes of baryogenesis, the proposed mathematics of the inflaton field, etc.
SteveL
not rated yet Sep 23, 2012
What we see 13.5 billion light-years away, is literally what happened there 13.5 billion years ago (because that's how long it took that light to reach us.)
Was the universal expansion calculated into this figure? Did it take the photons 13.5 billion years to reach us and therefore this galaxy was closer than 13.5 billion LY away? Or was it actually 13.5 billion LY away and the photons took longer than 13.5 billion years to reach us due to universal expansion? It has to be one or the other.

This is in one direction only. What do you want to bet that we will find similar galaxies in just about every direction? And, if it was at this location 13.5 billion years ago, due to continued and accelerating universal inflation; how far away are it and the other distant galaxies now, after 13.5 billion more years? Seems awfully challenging to state the age of the universe when we don't really even know its size, or where our patch is located in it.
Pressure2
1 / 5 (1) Sep 23, 2012
PE: There seem to be some confusion between the words began and ended, read the last sentence. Acording to this source the few centimeters expanded by a factor of 10 to the 50th power! Without doing the math it would very likely be larger than the visible universe today.

"During this period the Universe expanded at an astonishing rate, increasing its size scale by about a factor of 1050. Then, when the phase transition was complete the universe settled down into the big bang evolution that we have discussed prior to this point. This, for example, means that the entire volume of the Universe that we have been able to see so far (out to a distance of about 18 billion light years) expanded from a volume that was only a few centimeters across when inflation began!"

http://csep10.phy...ion.html
Pressure2
5 / 5 (1) Sep 23, 2012
You bring up some interesting points Steve L. If I am not mistaked the light we see from the 13.2 billion light year distant galaxy has taken 13.2 billion years to reach us. The redshifted light was emitted from that galaxy 13.2 billion years ago. The expanding universe has meerly redsifted the light we see. Also this 13.2 billion light year old galaxy not where we see it today, it much further away today.
ValeriaT
1 / 5 (1) Sep 23, 2012
The Standard model already considers, that the actual size of the observable Universe is way larger, than it correspond its age due the omnidirectional expansion of space-time. The diameter of observable Universe is calculated to 93 Glyrs. But it doesn't allow the red-shift larger than z=9 for observable objects and each larger z introduces a stress to Standard Model.
cantdrive85
1 / 5 (2) Sep 23, 2012
And the "dark ages" of astrophysics continues, future generations are going to laugh hysterically at the absolute nonsense current astrophysics has become. Tesla was correct to say that theoreticians of the standard model are metaphysicists and not scientists at all.
Lurker2358
1 / 5 (1) Sep 23, 2012
At the end of the inflationary epoch, this entire sphere had a radius of just a few centimeters. Subsequent expansion into its present size, occurred under more "normal" conditions, without strong contribution from the inflaton field.

The key is that such inflation and subsequent expansion occurred at every point of the pre-BB manifold (which was presumably also infinite in extent.)


Impossible.

The rate of hubble expansion is not high enough to explain how the universe could have expanded from THAT value to it's present size, or even it's apparent size "13 billion years ago" in the time allowed.

Even if the universe did come from a BB, it would have needed to be 13 billion years radius 13 billion years ago.

It is far more likely that the observable universe was created approximately "As is," rather than expanding from an nearly infinitely dense condition you describe.

Why didn't it immediately collapse into a black hole as soon as gravity existed?
Lurker2358
1 / 5 (1) Sep 23, 2012
ctd.

The main reason inflation was incorporated into the standard model of cosmology, was not to explain the size or rate of expansion of either spacetime or the observable horizon. Rather, its purpose was to explain why matter seems to be distributed through the universe as uniformly as it is, because under the orthodox model the clumping of matter should have been a lot more severe due to gravitational interactions that amplify quantum-scale fluctuations early in the Big Bang.


If you call billion solar mass black holes vs virtually empty space as "uniform" you need your head examined, as do cosmologists.

there is nothing symmetric or uniform about obserable matter. Even our own galaxy is asymmetric and is colliding with(in one case,) and orbiting nearby dwarf galaxies. There's nothing uniform about that distribution.

Even on absurdly large scales, you can find enormous voids of missing matter, and matter filaments, as well as other non-uniform structures.
Lurker2358
1 / 5 (1) Sep 23, 2012
That's the problem with singularities in general. All math and logic breaks down at a singularity, which is one reason I personally don't believe singularities in fact exist in reality (but rather, IMHO, are an artifact of incomplete mathematical models.)


I coudl say a lot about this, and it's true our mathematics sucks at dealing with the concept of black holes and other singularities.

Personally, I think a black hole's event horizon is approximately equal to it's physical surface. the nuclear forces have failed, by the Conservation laws have not. Therefore the black hole's inner matter should be "holding up" matter above itself, ironically due to the normal force and newton's laws, i.e. "for every force there is an equal and opposite force". Therefore, internally, gravity should "somehow" be pushing out just as strong as it is pulling inwards, preventing a "true" singularity from existing.

What you have is a sub-atomic particle of stellar mass and macroscopic radius.
Lurker2358
1 / 5 (1) Sep 23, 2012
I haven't said anything about any sort of steady state. Indeed, expansion of a formerly-compressed Universe is kind of an opposite of a steady-state. (And I will continue to insist on correcting your terminology: Big Bang is not an explosion, and was never formulated as an explosion. Big Bang is an expansion -- omnidirectional stretching -- of a four-dimensional manifold of infinite extent.)


If that's true, space dimensions should not be expanding faster than time dimension(s,) a hyper-sphere's radius is one value, after all.

Two points on the surface could expand away from one another such that a line drawn between them THROUGH the hypersphere would be expanding at or near the speed of light, but the surface of the hyper-sphere would still not be expanding by large multiples or orders of magnitude above light speed, but rather by a small multiple of "Pi".

This means the spacial diameter of the universe can't be much more than twice the age of the universe.
Pressure2
2.5 / 5 (2) Sep 23, 2012
Here is another link that supports what I have maintained all along, that the inflationary period expanded the universe to at least the size we see today in a tiny fraction of a second.

"Extremely small portion of Universe ballooned outward in all directions at speeds much greater than speed of light
Becomes many billions of times its original size to become visible Universe of today"
http://zebu.uoreg...ion.html
ValeriaT
1 / 5 (2) Sep 23, 2012
The people so far missed the fact, the things not only cools itself, when we get into cosmological/large scale - but they're getting hot and blue-shifted when we approaching the quantum/microscopic scale. This applies to observation in visible light, for EM waves longer than the wavelength of CMBR radiation both dependencies are reversed. The whole universe appears symmetrical around human observer scale in this way. IMO it's the result of very global observational geometry of random reality with its large and complex fluctuation of it.
Fleetfoot
not rated yet Sep 24, 2012
Here is another link that supports what I have maintained all along, that the inflationary period expanded the universe to at least the size we see today in a tiny fraction of a second.

"Extremely small portion of Universe ballooned outward in all directions at speeds much greater than speed of light
Becomes many billions of times its original size to become visible Universe of today"
http://zebu.uoreg...ion.html


The quote is correct but it only gives a ratio. On other sites you will see it said that in rough terms, the "observable universe" expanded from smaller than an atom to about the size of a grapefruit during that period. Thereafter the expansion has been much slower.

The plasma that emitted the CMBR was about 41million light years away at the time and is now about 42 billion light years away.
Fleetfoot
not rated yet Sep 24, 2012
I've said it before & I'll say it again: With HUDF-JD2 sitting out there, a galaxy as big as Andromeda at 13.1 Gyr, I stopped being convinced years ago that the Universe is 13.66 Gyr old (going by the integral used in red-shift calculators).


Bear in mind that Hubble is very limited in infra red, JD2 is obviously the tail of the distribution. It is probably not incompatible with the latest simulations that account for DM decoupling before normal matter.

There go all the red-shift calculators- Yeah Fleet, I tore that integral apart, it's one of the most concocted pieces of calculus I've ever come across.


If you mean solving for the age of the universe from the scale factor equation, it's quite simple. I have a crude Excel sheet version for the matter-only case that shows how it works.
Pressure2
1 / 5 (1) Sep 24, 2012
Fleetfoot: Your sheet is garbage in, garbage out. Sorry but if it is the one you posted before it is just wrong.

There is just one way to correct flatness of the visible universe and that is for the inflationary period to have expanded the universe to at least the size of we obserse today.
Pressure2
1 / 5 (1) Sep 24, 2012
This link does give the figures where you can do the math. I posted it before. Expand 3 centimeter by 10 to the 50th power. A Wiki link even claimed the inflationary period expanded the universe by 10 to the 78 power. What part of the last sentence don't you understand?

"During this period the Universe expanded at an astonishing rate, increasing its size scale by about a factor of 1050. Then, when the phase transition was complete the universe settled down into the big bang evolution that we have discussed prior to this point. This, for example, means that the entire volume of the Universe that we have been able to see so far (out to a distance of about 18 billion light years) expanded from a volume that was only a few centimeters across when inflation began!"

http://csep10.phy...ion.html

Meyer
1 / 5 (1) Sep 24, 2012
That's the problem with singularities in general. All math and logic breaks down at a singularity, which is one reason I personally don't believe singularities in fact exist in reality (but rather, IMHO, are an artifact of incomplete mathematical models.)


I could say a lot about this, and it's true our mathematics sucks at dealing with the concept of black holes and other singularities.

There is no need for models to do anything with singularities. Due to time dilation, black holes take an infinite amount of time to form (from every perspective in the universe other than the black hole's) and they evaporate in finite time, so the singularity limit is never reached. Same with the big bang: this supposed creation event would be an infinite time in the past for all observers other than a mythical entity experiencing the passage of fictional "cosmic time".
Fleetfoot
5 / 5 (1) Sep 24, 2012
This link does give the figures where you can do the math. I posted it before. Expand 3 centimeter by 10 to the 50th power. A Wiki link even claimed the inflationary period expanded the universe by 10 to the 78 power. What part of the last sentence don't you understand?

"the entire volume of the Universe that we have been able to see so far (out to a distance of about 18 billion light years) expanded from a volume that was only a few centimeters across when inflation began!"


The last word should read "ended". See for example this page by John Gribben:

http://www.lifesc...osmo.htm

Search for the word "grapefruit" and look through the article for the times.
Pressure2
3 / 5 (2) Sep 24, 2012
No Fleetfoot, "began" is the right word. Whose John Gribben anyways? The two link I provided you were university links, much more credible.

PS No I did not search for the word "grapefruit", I ususally only read sites like NASA, universities and a few other sites that I think will give good reliable information. Believe me you can even find conflicting information on those sites.

Pressure2
1 / 5 (1) Sep 24, 2012
The bottom line is the inflationary period had to have expanded the universe out to as far as we can see because the light arrives at us in nearly straight lines from every direction almost to the very beginning of the BB when you count the CMBR. There is only one other way around that, we are at the center of the universe.

ValeriaT
not rated yet Sep 24, 2012
..we are at the center of the universe..
which is indeed somewhat strange, as it brings the privileged position for human observers and it violates the cosmological principle. But it's quite natural for every tourist, who is walking across fog - he will always see himself at the center of his visibility scope, wherever he moves on...
Fleetfoot
5 / 5 (1) Sep 25, 2012
No Fleetfoot, "began" is the right word. Whose John Gribben anyways? The two link I provided you were university links, much more credible.

PS No I did not search for the word "grapefruit", I ususally only read sites like NASA, universities and a few other sites that I think will give good reliable information. Believe me you can even find conflicting information on those sites.


Gribbin is the author of well known books on inflation. This site is the home page of Andrei Linde (whose name should be familiar!) and in the paragraph after his CV he recommends Gribbin's book. Linde was one of the original authors of the theory.

If you search for "grapefruit inflation" in general, you'll find many sites say the same thing, the observable universe grew from smaller than a proton to the size of a grapefruit during that era. You are right that a larger volume would have grown to much larger size but the bulk of that would never be observable.