The James Webb Space Telescope never disproved the Big Bang. Here's how that falsehood spread.

Page 2 - Seeking answers about space? Join the Space community: the premier source of space exploration, innovation, and astronomy news, chronicling (and celebrating) humanity's ongoing expansion across the final frontier.
I'm going to disagree with the idea that it is fine to tell the general public that an unverified theory is fact. I think that actually hurts scientists when those theories need to be revised.

Remember, that popular press plays up the wow factor, emphasizing things like "The whole universe was once a tiny spec which exploded into astronomical size in seconds, far outstripping the speed of light!!!!!!!!!!!!!!!!"

If we eventually realize that it was not such a rapid "bang", then the media will play-up how wrong the BBT was about that. That's what they do. And "scientists" are one of their favorite foils.

So, credibility is lost, and that hurts when good science predicts things need attention and correction that a lot of the public don't really want to bother with. It is bad enough when we are straight forward saying there is a lot of uncertainty in things (which we typically underestimate) and reality comes our beyond our error bars. But, when we say something is an absolute fact and it turns out to be wrong, then the response is more like "You lied!"
 
"Remember, that popular press plays up the wow factor, emphasizing things like "The whole universe was once a tiny spec which exploded into astronomical size in seconds, far outstripping the speed of light!!!!!!!!!!!!!!!!"

Unclear Engineer in post #26. Some may want to read comments in this earlier thread, https://forums.space.com/threads/the-big-bang-what-really-happened-at-our-universes-birth.53947

When you apply Alan Guth paper of December 2013 to the original size of the universe during inflation, it starts out much smaller than an electron in diameter and now is about 93 billion light years in diameter. Did cosmology and astronomy measurements change from the 1933 sources I referenced? Yes, very much. :)
 
When you apply Alan Guth paper of December 2013 to the original size of the universe during inflation, it starts out much smaller than an electron in diameter and now is about 93 billion light years in diameter. Did cosmology and astronomy measurements change from the 1933 sources I referenced? Yes, very much. :)
Anything that small will come with no measurements. What measurements are you suggesting?

It's extrapolations using assumed values for the many variables. The best we have, apparently, is the LHC lab results down to just after the first trillionth of a second, which is after most Inflation models, especially Guth's. That doesn't mean the physics is necessarily wrong, and their may be relatively good reasons to think it is close to being accurate. But this aspect of the BBT, if one even ones to force BBT to go there, may be more metaphysics, especially if we have no conceivable way to test they hypothesis. This has been a problem for Inflation theory all along since it seems a bit ad hoc. Yet, it does such a nice job of solving the two problems, including the great level of isotropy discovered.
 
Helio and post #28 asked, "Anything that small will come with no measurements. What measurements are you suggesting?"

If you read the 1932 and 1933 sources I cited, the universe then was about 1 billion light years in radius with a mean density said to be 4 x 10^-28 g/cm^3 based upon observations available during that period.

"A mean density of the universe of 4 x 10^-28 gm/cm^3 is calculated from the observed expansion rate for a universe with no cosmological constant or curvature.", ref -https://ui.adsabs.harvard.edu/abs/1932CoMtW...3...51E/abstract, and https://www.pnas.org/doi/abs/10.1073/pnas.18.3.213, 15-March-1932, PDF report attached.

Today using the cosmology calculators available, the CMBR appears in a universe about 41 million light year radius or 82 million light years in diameter. What observations in astronomy demonstrate this was the actual size of the universe when the CMBR light appears, perhaps 380,000 years after the postulated BB event? This points out something that Unclear Engineer discussed about astronomical observations before the CMBR appears.

If you use the cosmology calculators and plug in the value for H0 = 500 km/s/Mpc when George Gamow developed the hot big bang model, the universe would be close to 6 million light years in radius using redshift 1100 like what is said for the CMBR today. It is very apparent that much revision in measurements took place to fit *observations* with the BBT rather than predictions made that fit nature-based observations. Your post #28 mentions, isotropy of the CMBR. This was never predicted. The inflation model developed to get around the light-travel-time problem in explaining what is seen in the CMBR today (known as the horizon problem, discussed in early 1980s Scientific American reports). Other groups developed Variable Speed of Light or VSL to explain the nearly uniform temperature and smoothness of the CMBR seen, not what was originally predicted.

When it comes to promoting the BB model to the public, items like what I document should be fully disclosed along with the reporting. That is why I called for a full disclosure on all the tweaks made to keep the BB model held up. Science, however, will likely never abandon BB model until a better paradigm is developed to replace it. However, all the cracks and holes in the theory should be disclosed.
 
  • Like
Reactions: Unclear Engineer
Today using the cosmology calculators available, the CMBR appears in a universe about 41 million light year radius or 82 million light years in diameter. What observations in astronomy demonstrate this was the actual size of the universe when the CMBR light appears, perhaps 380,000 years after the postulated BB event?
The CMBR observations themselves speak loudly to many aspects of cosmology including the size at the time of emission. The predicted temperature of a Planck distribution of around 3000K that is now reached us today at 2.73K establishes an important indicator due to redshift. But there is a great deal more than has been gleaned from the CMBR.

If you use the cosmology calculators and plug in the value for H0 = 500 km/s/Mpc when George Gamow developed the hot big bang model, the universe would be close to 6 million light years in radius using redshift 1100 like what is said for the CMBR today. It is very apparent that much revision in measurements took place to fit *observations* with the BBT rather than predictions made that fit nature-based observations.
Revising one's actual measurements to achieve a desired outcome is always dishonest. Science rarely works that way, though we both could argue it does happen in certain fields of endeavor.

Nevertheless, "saving the appearances" does happen in science more regularly. Tweaking a theory or hypothesis is often done with more accurate measurements. It was the accurate measurements of Tycho that was the basis of Kepler tweaking the Copernican model to fit the observations. The Ptolemy model was soon debunked by Galileo, leaving only the Tycho model and Copernican model to explain the World's motions. Kepler saw the Tycho model as ad hoc, IMO, so he tried to reconcile the problems, and did. [FWIW. It's fair to note that no one has ever debunked the Tycho model, but it sits in downtown Sillyville until someone can demonstrate reasonable arguments that justify all the fictious forces required to make the model work.]

The merits to BBT should not be limited to the work from even 4 decades past, much less 8 decades. Lemaitre (1927) was the first estimate of expansion with a higher H value of 630kps/Mpc. But he was explicit that this was a crude attempt since a lot more measurements with far greater accuracy than Slipher's and Hubble's values would be needed. When he translated his original paper into English, he intentionally left out the expansion rate work because, per one researcher (Livio), Hubble had published improved much better values.

Hubble's 1929 value of H was 500 (1929). Robertson found 460 (1928). Hubble's value was based on the crude values he got from Cepheids found in six galaxies, thirteen values from the assumption that the brightest stars has the same intrinsic luminosity, and a couple measurements in the Virgo cluster. (Peebles, pg.44).

Your post #28 mentions, isotropy of the CMBR. This was never predicted.
Any evidence this is true? There would be no CMBR if not for a high degree of isotropy. Little to no isotropy would mean Recombination would not happen essentially at the same time, thus observing it would be unlikely. [But, as you next note, when particle physicists stepped in they introduced far more anisotropy.]

Homogeneity has always been a major aspect of Einstein's GR and nearly every effort in dealing with the BB.

The inflation model developed to get around the light-travel-time problem in explaining what is seen in the CMBR today (known as the horizon problem, discussed in early 1980s Scientific American reports). Other groups developed Variable Speed of Light or VSL to explain the nearly uniform temperature and smoothness of the CMBR seen, not what was originally predicted.
The variable speed idea is a valid scientific hypothesis, but the evidence against this has grown fairly strong. If it is applied only during the first Planck seconds, then we have no way to test it.

When it comes to promoting the BB model to the public, items like what I document should be fully disclosed along with the reporting. That is why I called for a full disclosure on all the tweaks made to keep the BB model held up.
How "full" do your require? Again, I encourage you to read Peeble's book as he shows this history behind BBT, including all, or most, of the early errors. This helps show just how robust the theory is today.

Science, however, will likely never abandon BB model until a better paradigm is developed to replace it. However, all the cracks and holes in the theory should be disclosed.
I have cracks and holes in my Mustang, but it drives just fine. You'll need to introduce bigger cracks and holes to cast the level of doubt on BBT as you seem to wish to do. I hope you can because this is the exciting part to science. :)
 
Helio in post #30 states, "Any evidence this is true? There would be no CMBR if not for a high degree of isotropy. Little to no isotropy would mean Recombination would not happen essentially at the same time, thus observing it would be unlikely. [But, as you next note, when particle physicists stepped in they introduced far more anisotropy.] Homogeneity has always been a major aspect of Einstein's GR and nearly every effort in dealing with the BB."

Helio, are you saying here there is no light-travel-time problem (horizon problem) explaining the isotropy of the CMBR observed today? Others speak clearly this is a problem.

https://ui.adsabs.harvard.edu/abs/1984SciAm.250e.116G/abstract, "The inflationary universe Show affiliations Guth, A. H.; Steinhardt, P. J. "Abstract The theory of the inflationary universe is discussed. The problems facing the standard big-bang model are described, including the horizon problem, the smoothness problem, and the flatness problem. The combination of grand unified theories and the standard picture explains the asymmetry of matter and antimatter in the universe, but raises the problem of monopoles and domain walls. How the inflationary picture solves or avoids these problems is shown. The original inflationary theory is contrasted with the new inflationary theory, and the theoretical roles of supercooling, Higgs fields, symmetry-breaking, the false vacuum, the energy-density function, and the slow-rollover transition are discussed. The possibility that the actual creation of the universe is describable by physical laws is considered."

Helio, you also mentioned some earlier sources before the sources I cited from 1932 and 1933. I am not aware that during this time period, astronomers taught that 4D space would expand faster than c velocity, even during the time of George Gamow. I see nothing that shows Einstein taught this cosmology concept. That is another tweak needed for the BB model to work with large redshifts seen today. So, we have a light-travel-time problem in explaining the isotropy of the CMBR today and 4D space requirement must expand faster than c velocity. While this may not overthrow the BBT as you like to call the paradigm, it does show the cracks are larger than what you see in your car :)
 
Last edited:
Helio, are you saying here there is no light-travel-time problem (horizon problem) explaining the isotropy of the CMBR observed today?
No. I am asking you to present some evidence of your claim that the CMBR isotropy "was never predicted". That is a bold claim you're making. I don't mind be surprised if this is true, but I find it not credible given the importance of homogeneity, etc. If you ignore this question, I'll simply assume you have no evidence.


Helio, you also mentioned some earlier sources before the sources I cited from 1932 and 1933. I am not aware that during this time period, astronomers taught that 4D space would expand faster than c velocity, even during the time of George Gamow.
Right, they had no reason to consider this until after the CMBR was discovered. The Horizon problem came thereafter, IIRC, as a result of the incredible degree of isotropy of the CMB. Inflation may be a bit "ad hoc" but it does exhibit credibility. It does require expansion faster than light, but it seems clear that no one can demonstrate GR disallows this. [Yes, I realize the CMBR is also a region that exceeds c.]

That is another tweak needed for the BB model to work with large redshifts seen today. So, we have a light-travel-time problem in explaining the isotropy of the CMBR today and 4D space requirement must expand faster than c velocity.
I don't see any real problem with redshift and the CMBR. As I mentioned, the CMBR was a prediction from GR. Gamow and others predicted specific values for the microwave wavelength, though they had only rough time frames to go by. I think Gamow came close, at least in one measurement, with his 5K temperature estimate. I think Dicke, year later, was able to refine it to a closer value. His team was construction an antennae dish to verify his hypothesis when he got the famous call from Wilson and Penzias.

These temperatures, of course, are tied to the redshift estimates for the CMBR. The temperature values are of a Planck distribution of all the wavelengths emitted during Recombination.
 
Helio, in your post #32 it is apparent that you do not accept or acknowledge that the BB model has a distinct, light-travel-time problem in the CMBR isotropy seen today known as the horizon problem. I will say yes, the CMBR isotropy and temperature we see from Earth today does have a light-time issue and thus horizon problem. Here is my *plain language summary* based upon my understanding of this problem from published sources, including the 1984 source I cited that shows it is real in the standard BB model (without inflation tweak).

Accepting that the CMBR became visible light when it cooled to a uniform temperature of say 3,000-3500 K, what is the radius of the universe then? Using the cosmology calculators and H0 ranging 67 to 72 km/s/Mpc with a redshift z about 1100 today for the CMBR, that radius is about 40 to 41 million light years when the CMBR appears at those temperatures as light. What is the radius today using H0 and CMBR redshift 1100? At least 46 billion light years from Earth. All of this evolution of the cosmic fireball with cooling temperature takes place over some 13.8 billion years while the evolution of the universe expands from about 41 million light years radius to 46 billion light years today (faster than c velocity). From Earth we see a nearly uniform 3K background glow, no matter what angular size we observe in the sky. Unless you can show that the CMBR can cool like this with such isotropy and nearly uniform temperature, you need inflation tweak, otherwise there is a light-time problem explaining the origin of the CMBR seen today.
 
Accepting that the CMBR became visible light when it cooled to a uniform temperature of say 3,000-3500 K, what is the radius of the universe then? Using the cosmology calculators and H0 ranging 67 to 72 km/s/Mpc with a redshift z about 1100 today for the CMBR, that radius is about 40 to 41 million light years when the CMBR appears at those temperatures as light. What is the radius today using H0 and CMBR redshift 1100? At least 46 billion light years from Earth. All of this evolution of the cosmic fireball with cooling temperature takes place over some 13.8 billion years while the evolution of the universe expands from about 41 million light years radius to 46 billion light years today (faster than c velocity). From Earth we see a nearly uniform 3K background glow, no matter what angular size we observe in the sky. Unless you can show that the CMBR can cool like this with such isotropy and nearly uniform temperature, you need inflation tweak, otherwise there is a light-time problem explaining the origin of the CMBR seen today.
I trust your calculations and your use of the calculators.

It is well-recognized that you don't need much of a z value to find space receding from us with c > 1. Observing regions that were traveling faster than light at the time of their emission is not a problem in cosmology. This is only true to a point, of course.

I don't doubt Inflation theory will get tweaked, but remember that it is installed into BBT to tweak BBT to present a credible (depending on which cosmologist you ask, no doubt) answer to the horizon problem. It does a great job to give us the observed isotropy, but Inflation has no direct means of testing, even in a lab. So that makes it harder to accept, and rightfully so.

Does this put us on the same page?
 
  • Like
Reactions: rod
I trust your calculations and your use of the calculators.

It is well-recognized that you don't need much of a z value to find space receding from us with c > 1. Observing regions that were traveling faster than light at the time of their emission is not a problem in cosmology. This is only true to a point, of course.

I don't doubt Inflation theory will get tweaked, but remember that it is installed into BBT to tweak BBT to present a credible (depending on which cosmologist you ask, no doubt) answer to the horizon problem. It does a great job to give us the observed isotropy, but Inflation has no direct means of testing, even in a lab. So that makes it harder to accept, and rightfully so.

Does this put us on the same page?
Not really Helio but at least there is some acknowledgement of the horizon problem here in the BB model :)
 
Not really Helio but at least there is some acknowledgement of the horizon problem here in the BB model :)
Agreed. The horizon problem is only solved, apparently, if Inflation actually happened. Of course, there are many versions of this add-on theory.

There is also the Flatness problem, where omega(today) = 1, to within perhaps 1%. But the mass density of the early universe could be argued to have been some random value, yet it is as if it was finely tuned. I think many know why, of course, but on a pure science level there isn't any explanation.... except, once again, Inflation seems to handle this problem as well.

There is also kind of a third problem - monopoles. The GUT and other unifying models argue for very powerful magnetic monopoles that should be detectable, yet none have been found. Guth argued in the 80's how Inflation solves that issue as well.

My arguments aren't to say there are no weaknesses to BBT, but to not let these weaknesses be over-stated given the incredible strengths found in BBT. And, once again, Inflation has been introduced to solve these problems, but it's beyond modern science to test this directly, only indirectly.

I just got a pop-up from Space.com about another remarkable success test for GR. But even Einstein had to tweak his original equations, and he had to rush them as Hilbert was very close to beating him to the punch. In fact, Einstein's first calculation for the deflection of light was off by about a factor of 2, which would have been quite a lot of egg on his face had his eclipse expedition actually got any results, but no images were taken due to Russian seizure. :)
 
  • Like
Reactions: rod
Helio in post #36 commented, "There is also kind of a third problem - monopoles. The GUT and other unifying models argue for very powerful magnetic monopoles that should be detectable, yet none have been found. Guth argued in the 80's how Inflation solves that issue as well."

Yes, my readings on this indicate the monopoles are as stable as hydrogen and would fill our universe today if not for inflation. They get pushed out of universe during inflation into some other universe that evolves. Otherwise, we may see stars today made up of monopoles :)

From my home database. This is a quick summary of the S&T report, 'Cosmic Collisions' in the December 2012 issue which reviewed the multiverse or bubble cosmology.

"Efforts are underway in cosmology to establish that the big bang is part of an eternal inflating universe which during the early inflation period, about 1E-35 second after the big bang, some bubbles collided with our universe and left behind fingerprints in the cosmic microwave background radiation or CMBR that point to other universes and bubbles in cosmology. These bubble fingerprints could support that the universe is just part of a grand multiverse that is eternal and according to string theory, perhaps 1E+500 different universes exist (p. 23). Cosmologists are studying intently WMAP data and waiting for results from the European Space Agency Planck spacecraft measurements to look for evidence of past colliding bubbles in the CMBR. Some problems were discussed in the big bang model that inflation solves like the missing magnetic monopoles, uniformity of space in all directions and the flatness problem of the universe. The largest conflict between calculation and observation was discussed, namely dark energy influence should be > 1E+100 larger than observations allow. This is considered to be the largest discrepancy between theory and observation in science. However the multiverse using string theory could solve this. As the report stated – “String theory could solve this problem if multiple universes exist. The theory implies the existence of 1E+500 different types of empty space, with different particles, forces, and amounts of dark energy allowed in each, Guth explains. If instead of just one, every one of these 1E+500 possible solutions is correct – meaning each solution matches a different universe that exists in a larger multiverse – then dark energy’s value isn’t weird at all. We just live in one of the universes where the amount of dark energy is what we measure it to be, a value particularly friendly to our existence. These theoretical arguments do not constitute direct evidence for multiple universes. But such evidence might be found. The infinite, higher-dimensional multiverse (the cheese in the Swiss cheese) into which these bubble universes are born would expand faster than any of its individual bubbles, but if enough universes popped into being in this landscape, some of them might form close enough to collide with our own. This collision could leave a temperature bruise in the CMB’s mottled surface shaped like a faint, round disk. Such a disk would consist of photons that are slightly warmer (or cooler) than the surrounding CMB, anomalies that are even weaker than those that show up in the iconic map from NASA’s Wilkinson Microwave Anisotropy Probe (WMAP). That’s saying something, because the CMB’s 2.7-kelvin temperature deviates by at most 0.0002 kelvin from one point to another across the entire sky.” – page 23.

Carlisle, C. M., Cosmic Collisions, Sky & Telescope 124(6):20-26, 2012 (December)

Note, "Some problems were discussed in the big bang model that inflation solves like the missing magnetic monopoles"

Someone else gets the over production of magnetic monopoles in their universe that pops up during inflation and evolves :)
 
  • Like
Reactions: Helio
Someone else gets the over production of magnetic monopoles in their universe that pops up during inflation and evolves :)
I don't think they emerge during inflation but seem to take place just prior to it at temperatures well-beyond anything we can produce. These many theories (GUT and the variations of it) are more in the realm of metaphysics, when gravity was on a par with the other forces, IIRC. A theory requires observable direct or indirect tests. I suppose if it nicely explains all the subsequent events, and perhaps makes some new predictions that can be discovered, it will generate credibility. I'm not smart enough to know where this might be today.

The limited impression I have is that Guth was able, to some degree, demonstrate how Inflation somehow solves the monopole problem.
 
Frankly, I don't see any difference between (1) us just happening to be in one of the universes in the multiverse that has the natural law values we observe, and (2) the natural law values that we observe are just random occurrences for the only universe.

Such thinking just seems to be used to absolve the theorists from needing to explain why the values we observe are what they are.

Personally, I want to see some consistency in the understanding of how things work.
 
Sep 22, 2022
1
0
10
I was disappointed by the article that implies that people who question the Big Bang Theory are conspiracy theorists, and are in the same category as flat earthers and vaccine deniers.

I am inclined to think that the universe is infinite in space and time and that it is not expanding. However, I do not believe this like a person might believe in the idea that Bill Gates puts microchips into vaccines. I do not think that a secret cabal or One World Government run by the Illuminati or alien lizard people know “the truth” about an infinite universe and are suppressing it with the “lie” of the Big Bang theory, as they apparently did with the faked moon landing.

The Big Bang is an excellent theory that, up until this point, explains the facts as we know them. It is not a theory that I necessarily believe in, and this is why I am interested in the evidence that the James Webb Space Telescope will give us. It may well be that future photographs will confirm the formation of the universe 13.8 billion years ago.

However, I would like to guess that as the JWST looks deeper and deeper into the universe it will find fully formed galaxies that are older than the supposed age of the universe itself with a red shift of astronomical proportions! :)

I do not know this for a fact. It is a guess.

But I am awaiting the evidence. If the JWST was to discover a galaxy that is, say, 20 billion years old, or 50 billion years old, then the Big Bang Theory would have to be revised, either by pushing the supposed start of the universe back further in time, or abandoning the theory altogether.

This has not happened yet. So far, the JWST has not “disproved” the BBT, nor has it “proved” it.

It may well be that the JWST discovers little embryonic galaxies that confirms the 13.8 billion year old universe and the BBT. In which case, I will gladly eat my hat.

Conspiracy theorists are not interested in evidence, and no amount of evidence for the roundness of the planet will convince a flat-earther or change their mind.

But I am happy for my mind to be changed. I am eagerly awaiting further evidence from the JWST. The hypothesis of an infinite non-expanding universe is just a hypothesis, not a religious truth. It might be disproved, or further evidence might call the BBT into question. Or it might not. I think that the BBT is also a hypothesis which may or may not be disproved.

We will wait and see. But I do not think that this article, putting people who question the Big Bang into the same category as people who deny the moon landing, is that helpful.
 
"Inflation" seems to do a lot of things to address a lot of problems with the BBT, but somehow doesn't do anything to complicate the BBT story. Which makes for a real credibility problem when nobody has any idea what caused it and how.

But, I don't see how the Webb or any other telescope can actually address whether inflation occurred or not. That part of the whole story seems to be based on the quantum mechanics theories coming out of the big atom smashers, not astronomy.

So, getting back to the Webb's capabilities, I think I remember somebody posting here that it is designed to be able to see objects redshifted by a factor in the mid 20s (25 or so). Considering that the Cosmic Microwave Background Radiation is theorized to be redshifted black body radiation from about 3000K hydrogen with a redshift value of 1080, there seems to be a lot of redshift to go to fill that observation gap. Do we have any plans to look into that gap with other technology? Radiotelescopes? Gravitational waves?

And, by the way, I find it difficult to really understand that gap, with various sources talking about age, distance and redshift without any correlation. The amount of time in that gap seems to be only about 400.000,000 years, a small fraction of the age of the universe in the theory. But, the redshift is a huge difference in multiples between, say 25 and 1080. And the distances in that gap are stated on several vastly different bases for the sources motion since the time of emission.

I realize that there are "calculators" on the Internet that purport to compute one measure from another, but they seem to be pretty arcane. Is there a table with columns for redshift, assumed time the light was emitted, distance from Earth at which that light was actually emitted, apparent distance from Earth due to expansion, and calculated actual distance from Earth "now" due to the motion since the light was emitted? Rows starting with redshift of 1 and going to at least 1100 would be useful, with increments of 1 up to maybe 35 or 50 redshift and then by 50s to 1100. Because things get very non-linear in the relationships, the increments used for the redshift that show where any sharp changes in the relationships occur would be the most useful.

I would do it myself if somebody will recommend a calculator that has all of that info. But, trying to use multiple calculators seems to get me into issues with assumptions that do not seem uniform to me.
 
  • Like
Reactions: rod
Concerning Unclear Engineer post #41, the CMBR redshift as seen from Earth today using the cosmology calculators, z ~ 1100 and comoving radial distance from Earth, ~ 46 billion light years radius. As discussed earlier in this thread, when the CMBR appears as light, the universe radius about 40-42 million light years using H0 67 - 72 km/s/Mpc. JWST measuring z ~ 25 with the CMBR z ~ 1100, there is plenty of room here for more space and interesting objects :) The CMB is said to form with black body spectrum and nearly uniform temperature today as seen from Earth, near 3 K that redshifted and cooled as the universe expands.

However, as redshifts increase as measured from Earth, the CMB temperature (CMBT) must also increase and get warmer. I have some reports documenting this in astronomy so we should see redshifts increasing larger and larger, as well as the CMBT compared to our position on Earth (CMBT near 3 K).

Does this indicate that in the BB model, when you reach z ~ 1100, the cosmic fireball temperature is still in the 3000 K to 3300 K range surrounding the observable universe today? That would be about 46 billion light years radius from Earth today. This would be interesting to document in cosmology and in the BB model explanation for the origin of the CMBR.
 
As I understand it, the CMBR that we see right now was originally released as 3000K black body radiation (visible light) at a distance much closer to Earth than 13.4 billion light years. It took 13.4 billion years to reach us because that light was traveling through space as the space was expanding between where it was emitted and Earth, making the effective progress towards Earth much less than light speed when you divide the original distance by the travel time.

And, while that light was traveling in our direction, the matter that emitted it was traveling in the opposite direction for 13.4 billion years, and at a speed relative to Earth that was faster than the speed of light because space was expanding everywhere, and the total effect of all the space between Earth and that matter was making the total distance increase faster than light speed.

So, the matter that emitted the light has seen a lot of expansion since it was at 3000K abut 13.4 billion years ago, and should also have been cooled by that expansion. If I knew the distance from Earth at which the currently visible CMBR was emitted, and the distance it has travelled since then I could compute the current temperature of that area as (distance-at-emission/distance-now)^2 x 3000K, neglecting any heat contributions form the formation of stars and galaxies.

That should come out similar to the temperature of space in our vicinity, because the universe is assumed to be isotropic (same everywhere), so what is happening here now should also be happening there now. The problem is that we can't see there now.

And that gets me to another problem with understanding this. Different Internet sites seem to say different things about what the "observable universe" is. One is telling me that anything in the observable universe will always remain "observable", while another tells me that things 19 billion miles form Earth now will eventually leave the observable universe and yet anther tells me that things have already left the observable universe.
 
The Big Bang is an excellent theory that, up until this point, explains the facts as we know them. It is not a theory that I necessarily believe in, and this is why I am interested in the evidence that the James Webb Space Telescope will give us. It may well be that future photographs will confirm the formation of the universe 13.8 billion years ago.
Nicely put! This is how science works. Religion, IMO, is something one can "believe in", whereas science is more about "believing this or that" happened or is happening or will happen.

There is a certain probability, perhaps, that could be assigned to any given theory. Einstein gave the original idea of expansion or contraction per Friedman's equations (1922, IIRC) almost a zero probability of being a fair model for the physical universe, though Einstein later admitted the math was not wrong. But, he originally had not thought much about cosmology when he presented his works in late 1915 to 1916.

Today, if probabilities of the physicality of a model (theory) is a fair approach, then I would put the BBT in the 90% or better category. There are too many independent lines of evidence that all favor BBT. The biggest support for BBT is found in the many aspects of the CMBR, since it was predicted within this theory versus others (e.g. Steady State).

Of course, as you note, the IR ability of the JWST will take us farther back in time and space to add to the body of evidence either for or against the BBT. It might even help with the minor, but likely real, discrepancy Rod notes in the H0 values.

But, we should be mindful that the best results from the JWST won't be found in confirming BBT, but finding that something else is happening (or happened). That is called discovery, and that's what scientists love. This is how Nobel prizes are earned. :)
 
Last edited:
Unclear Engineer in post #43 raises some interesting points about CMBT and redshift. Here is an example of what I mentioned in post #42.

Microwave background temperature at a redshift of 6.34 from H2O absorption | Nature

"...This implies a microwave background temperature of 16.4–30.2 K (1σ range) at z = 6.34, which is consistent with a background temperature increase with redshift as expected from the standard ΛCDM cosmology4."

As we see larger and larger redshifts like a 25 perhaps for JWST, the CMBT will be much warmer than 3 K we see on Earth. Extrapolating like this leads to interesting concepts about the CMBT at z = 1100 where the CMBR is at today using the cosmology calculators (all based upon GR metric for expanding space, 4D space, not 3D space). That redshift of 1100 is not at 13.4 billion light years distance but near 46 billion light years radius from Earth. So, if JWST can observe a redshift of 25, what will the CMBT be for that redshift? It should be warmer than measured for 6.34 redshift object said to be some 16.4 to 30.2 K.

Using cosmology calculators like LAMBDA - Links to Calculators (nasa.gov) with z = 1100, light travel time distance is about 13.7 or 13.8 Gyr to Earth while the comoving radial distance is out near 46 Gly distance. So, if the CMBT can be measured, the larger redshifts should reflect increasing CMB temperature like if JWST observes and measures a redshift of 25. Extrapolating all the way out to z = 1100 results in the cosmic fireball 3000-3300 K.
 
Last edited:
A couple of comments on different issues:

1. As I understand the theory: Everywhere in the observable universe was at the same temperature (with minor variations) at the same time, when neutral hydrogen atoms formed from free electrons and protons. At that point in time, everywhere in the universe, became transparent to the passage of light (photons) which had previously been scattered by the sea of free electrons. So, the photons that were released at that point in time everywhere were suddenly able to travel to everywhere in the observable universe, initially as light with a spectrum looking like the black body emission spectrum with a temperature of about 3000K. Space continued, and continues to expand, stretching the wavelengths of that light by the same amount everywhere at any given point in time. So, the CMBR reaching the Earth as time goes on will continue to reflect the expansion of space , with an increasing redshift value that indicates a longer period of time and larger distance of travel from the point of emission of the light we are receiving at any point in the future. But, I don't think that change with time is detectable with current technology in the relatively short time interval we have been making observations. That is the theory. With the expansion rate being non-constant, apparently decreasing rapidly around the time of the CMBR emission 13.4 billion years ago, and then increasing a bit starting about 5 billion years ago, doing all of the back-calculations to make observations fit this theory involves a lot of math, not to mention a lot of assumptions. So, I have not tried to check the math, myself, and have just noted that not everybody is on the same page with their conclusions.

2. Trying to put quantitative probabilities on the likelihood that theories are correct or incorrect is totally useless. All it can do is quantify the amount of "group think" associated with each theory. The real uncertainty in theories is the "unknown unknowns" which simply cannot be quantified, because they are unknown. And, worse, the modelers who make their models have very large amounts of "confirmation bias" with respect to assessing the relevance of issues that are known to exist in the models, which leads to different "experts" coming up with much different "quantifications" of the probabilities that their particular models are correct. So, even averaging the probability estimates coming from proponents of competing theories is just a "garbage-in-garbage-out" process. It does make some sense to look at the confidence that specific aspects of some theories are correct. For instance, trying to decide if the redshift is due to motion of light-emitting object through space, or expansion of light wavelengths as light travels through expanding space, can be discussed in terms of correlations with other observations. But, once we get past the point where there are astronomy observations, we get into attempts to understand astronomy on the basis of observations in atom smashers, and we already know that we do not (yet?) have a theory that can successfully combine Relativity and gravity with quantum mechanics. So, there is plenty of room to doubt the BBT for the earlier parts of its story. But, I would not have any confidence on a quantification of the level of doubt or confidence as a "probability that the BBT is correct". The BBT has been undergoing major changes in the 50 years that I have been aware of it, so it previously was "wrong" in some details before, and almost certainly still so, now. Theories are always revised as new observations need to be accounted for. So, to me, what would need to be shown to make the BBT "wrong" would be that the observable universe was not once a tiny spec nearing a singularity. Even finding that the universe cyclically bounces between a tiny spec and a 100 billion light year diameter would still involve a "big bang", just more than one.
 
A couple of comments on different issues:

1. As I understand the theory: Everywhere in the observable universe was at the same temperature (with minor variations) at the same time, when neutral hydrogen atoms formed from free electrons and protons. At that point in time, everywhere in the universe, became transparent to the passage of light (photons) which had previously been scattered by the sea of free electrons. So, the photons that were released at that point in time everywhere were suddenly able to travel to everywhere in the observable universe, initially as light with a spectrum looking like the black body emission spectrum with a temperature of about 3000K. Space continued, and continues to expand, stretching the wavelengths of that light by the same amount everywhere at any given point in time. So, the CMBR reaching the Earth as time goes on will continue to reflect the expansion of space , with an increasing redshift value that indicates a longer period of time and larger distance of travel from the point of emission of the light we are receiving at any point in the future.
Yes, we are only seeing those photons that began their trek to us from the time of Recombination but are only reaching us now.

With the expansion rate being non-constant, apparently decreasing rapidly around the time of the CMBR emission 13.4 billion years ago, …
13.8 billion - ~400,000 still rounds to 13.8 billion.

I’ll give BBT better than a 90% chance if being the right theory. I’m curious what odds you give it?
 
  • Like
Reactions: COLGeek
I’ll give BBT better than a 90% chance if being the right theory. I’m curious what odds you give it?
As I just posted, putting probability or odds on a theory being "right" is a waste of time. It even depends on what your definition of "right" is. For the BBT, does "right" include a singularity (recently disavowed by some, but still believed by others)? Does it preclude any cyclical universe? Does it have to have the timing exact between "Planck time" and now?

The more detail you want to include in "right" lowers the odds that "right" is true.

Modelers have a saying: "All models are wrong but some models are useful." The ones that are useful are the ones that allow us to figure out useful things that we might not have otherwise directly understood. General Relativity is a great example of a model that has allowed us to realize and quantify that things we observe can be perceived differently due to velocity differences and proximity to masses, for instance, even though it does not actually tell us why that happens. We actually use that information for our GPS system here on Earth every day.

On the other hand, how has the BBT actually helped us, so far? It has suggested some still unperceived things to look for (e.g., "dark energy", "dark matter"), but we have not found them, so far. If we find them, then it will have been useful. But, if we instead find other explanations than the BBT predicts with its fitting parameters, then it may turn out that the BBT was a time-wasting distraction. The jury is still out.
 

ASK THE COMMUNITY