Is the Universe Infinitely Old and What Would We Expect to See?

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Discussion Overview

The discussion revolves around the concept of an infinitely old universe, exploring what one might expect to observe under such a premise. Participants delve into theoretical implications, measurement of time, and the nature of cosmic phenomena, including black galaxies and the behavior of matter and space over infinite time.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants propose that if the universe is infinitely old, one might expect to see 'black' galaxies made up of burnt-out stars.
  • Others argue that if gravity dominates, all matter could collapse into a supermassive black hole, while if it does not, the universe could consist of an infinitely thin gas at absolute zero.
  • A participant mentions that measuring time on a logarithmic scale could lead to the conclusion that the universe is infinitely old, but questions the physical meaning of such a measurement.
  • Another participant challenges the validity of using the cosmic microwave background (CMB) as a clock, stating that it only provides information back to a certain redshift and cannot be used to define time before that epoch.
  • There is a discussion about the implications of defining time based on different physical processes, such as atomic vibrations versus CMB photon frequencies, and how these definitions affect the understanding of the universe's age.
  • Some participants express skepticism about the usefulness of logarithmic time scales for defining absolute age, suggesting that linear units are more appropriate for such measurements.
  • A later reply questions the nature of space under gravitational compression and whether space itself can be compressed, raising further questions about the properties of such compressed space.
  • Participants discuss the need for a consistent method of measurement across space and time, referencing principles from general relativity and conformal gravity theories.

Areas of Agreement / Disagreement

Participants express a range of competing views regarding the implications of an infinitely old universe, the validity of different time measurement methods, and the nature of cosmic phenomena. The discussion remains unresolved with no consensus reached on these topics.

Contextual Notes

Limitations include the dependence on the definitions of time and the assumptions made about physical processes. The discussion highlights the complexities involved in measuring time and age in cosmology, as well as the challenges in reconciling different theoretical frameworks.

  • #31
SpaceTiger said:
As suggested by your equation, the upper limit on that integral should have been t_0, not t.
ST thank you - typo noted.

But I found your reply inconsistent - for if we have agreed that "t", coordinate time, is that recorded by atomic clocks then surely it does have physical significance?

Garth
 
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  • #32
Garth said:
But I found your reply inconsistent - for if "t", coordinate time, is that recorded by atomic clocks then surely it does have physical significance?

The parameter, "t", only appears in proportionalities, implying that it could be given an arbitrary normalization. A given one of these normalizations could be said to be physically significant, but the parameter itself only reflects a scaling.
 
  • #33
SpaceTiger said:
No Garth, it doesn't. The physically meaningful result, as I said in the original post and have repeated several times in this thread, is that the conformal time to the big bang converges for many reasonably cosmological models. This was in response to your claim:
Garth said:
If your clock 'ticking' is the inverse frequency of a CMB photon then there have been an infinite number of ticks since the BB.
.......
I was indeed thinking of the linearly expanding universe
Given that no mainstream cosmologist actually believes the linearly expanding model, this claim is deceptive, to say the least.
Just to defend my introduction of the idea here, rather than deliberately "peddlng" SCC, I was responding to the subject of the thread "An Infinitely old Universe", which itself is not mainstream.

Perhaps there should have been no posts in this thread at all?

Garth
 
  • #34
Garth said:
Just to defend my introduction of the idea here, rather than deliberately "peddlng" SCC, I was responding to the subject of the thread "An Infinitely old Universe", which itself is not mainstream.
Perhaps there should have been no posts in this thread at all?

There's nothing in mainstream theory that says the universe can't evolve to infinite age. Furthermore, I wasn't criticizing your reference to linearly coasting or SCC, I was criticizing your tacit assumption that the universe was governed by it.
 
  • #35
SpaceTiger said:
There's nothing in mainstream theory that says the universe can't evolve to infinite age.
I must have got the wrong impression, when the OP said
Chronos said:
Assuming the universe is infinitely old, what would, or would you not expect to see? I will start with 'black' galaxies composed of burnt out stars.
I assumed he meant the age into the past was infinite!
Furthermore, I wasn't criticizing your reference to linearly coasting or SCC,
Yes, but I should have made that clearer earlier - thank you for correcting me.
I was criticizing your tacit assumption that the universe was governed by it.
We wait and see! :biggrin:

Garth
 
  • #36
Just for the record, I see many problems with an infinitely [temporally] old, compared to a finitely old universe. The question is this... If you accept the proposition the universe is infinitely old, what observational differences should we expect from one that is not? PS, I'm intentionally avoiding introducing Olber's paradox [a very powerful argument] into this hypothesis.
 
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  • #37
Footnote: what really bothers me about this is you need steady state creation of 'new' matter to replace the 'old' matter that is consumed by stellar fusion. Where is the evidence of this? How is it more convenient to assume continuous creation of new matter, than a one time 'poof' incident? The 'poof' version seems easier to swallow. In that scenario you can at least claim the laws of physics had not yet kicked in. My last question is how do you explain why the CMB is not infinitely energetic?
 
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  • #38
Footnote: what really bothers me about this is you need steady state creation of 'new' matter to replace the 'old' matter that is consumed by stellar fusion. Where is the evidence of this? How is it more convenient to assume continuous creation of new matter, than a one time 'poof' incident? The 'poof' version seems easier to swallow. In that scenario you can at least claim the laws of physics had not yet kicked in. My last question is how do you explain why the CMB is not infinitely energetic?
To be the devils advocate - The CMB can be attributed to the new matter. That would be evidence. Also the CMB is not infinitely energetic because we only get a taste of it once, by way of the new matter, which is a finite sum. In this scenario there would be a center to the universe, and we would be close to it. Also in this scenario - All matter that is made eventually appears to be close to center in a universe that evolves outward from a central point.
Not that this is the case, but it is within the realm of possibilities.
 
  • #39
I disagree. Do the math that shows new matter emerges from that scenario. That will impress me.
 
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  • #40
In a linearly coasting model, where are the coasting redshift galaxies? The obvious answer ... there aren't any. So we back we go to the question: where are the high redshift galaxies superimposed in front of the low redshift galaxies? OMG, there aren't any! Arpians claim there is at least one such example... but amazingly avoid the discussion why there are not thousands of them.
 
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  • #41
Chronos said:
I disagree. Do the math that shows new matter emerges from that scenario. That will impress me.

We don't know where the energy for the BB came from either, but that never stopped anyone from looking for the answers.
 
  • #42
Chronos said:
In a linearly coasting model, where are the coasting redshift galaxies? The obvious answer ... there aren't any. So we back we go to the question: where are the high redshift galaxies superimposed in front of the low redshift galaxies? OMG, there aren't any!
Can't say I follow your question.
 
  • #43
Ask ST, he has a better explanation than I.
 
  • #44
Chronos said:
Ask ST, he has a better explanation than I.

I'm guessing you were making an assumption as to how the galaxies would look in the scenerio I mentioned, but I would say they will look like they do now ( increasing redshift over distance).
 
  • #45
A good question. I'm just saying we live in a temporally finite universe. Everything appears to age, hard to explain that in a universe that does not age.
 
  • #46
It goes to the bigger question... the Fermi paradox. Where are they? The answer, in my opinion, is you can't get here from there.
 
  • #47
Chronos said:
In a linearly coasting model, where are the coasting redshift galaxies? The obvious answer ... there aren't any. So we back we go to the question: where are the high redshift galaxies superimposed in front of the low redshift galaxies? OMG, there aren't any! Arpians claim there is at least one such example... but amazingly avoid the discussion why there are not thousands of them.

If you read my posts carefully you will see that I subscribe to two different ways of measuring the universe. With c a constant of nature in both, one has a 'photonic' clock and one has an 'atomic' clock as defined in my post #29.
We can define two physically significant times as follows:

Sample two photons, one emitted by a caesium atom the other sampled from the CMB radiation.

The first, an "atomic" second, is defined as the duration of exactly 9.19263177x109 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom.

The second, a "photonic" second, is defined as the duration of exactly 1.604x1011 periods of the radiation corresponding to the peak of the CMB black body spectrum.

Both systems of time measurement are physically significant and agree with each other in the present time, although they will diverge from each other at other times.

When compared to the atomic standard, the "photonic" clock in the linearly expanding model, extrapolated back to the earliest moments of the BB, diverges to (-) inifinity as atomic time t->0.

Thus in this model we can recover "an infinitely old universe" within an apparently finite (as measured by an "atomic" clock) BB paradigm.

The system that uses the 'atomic' clock' is that in SCC's Einstein conformal frame in which the universe is linearly expanding from a BB about 14 Gyr ago. Its advantage over the Mainstream model is that it does not require exotic DM or DE to be concordant, also as we have discussed it gives more time, about twice as much, for early structures to form in the high z ~ 6 - 10 universe, hence my interest in a possible age problem already apparent in the Mainstream model.

It is only in the Jordan conformal frame which uses 'photonic' time that the universe is eternal and static. Here atomic processes in the early universe are seen in slow motion but the physics is the same as before, only 'slower'.

It is not a Steady State or equivalent theory where matter/star/galaxies have to be regenerated. The 'slow motion effect' is a consequence of using this method of measuring time.

Galaxies are observed with cosmological red-shift, in the linearly expanding Einstein frame, which is interpretated as a Doppler effect;, in the static eternal Jordan frame it is interpreted as a mass-field effect.

I do not understand what you mean by "coasting galaxies", except the general understanding of GR that all galaxies are understood to be coasting along their geodesics through cosmological space-time.

In the linear expansion model as red-shift is cosmological, due to the universe's linear expansion, there should be no high z objects in front of low z ones.

I hope this has helped.

Garth
 
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  • #48
A question for Garth:

Is your measure of the age of the universe equivalent to the "affine distance" along a light-like geodesic from "now" to the "big bang"? (Converted to units of seconds).

Affine distance is defined in the following URL

http://relativity.livingreviews.org/open?pubNo=lrr-2004-9&page=articlesu4.html

I think it should be, because I think the affine parameterization of a light beam should "count wavelengths".
 
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  • #49
pervect said:
A question for Garth:
Is your measure of the age of the universe equivalent to the "affine distance" along a light-like geodesic from "now" to the "big bang"? (Converted to units of seconds).
Affine distance is defined in the following URL
http://relativity.livingreviews.org/open?pubNo=lrr-2004-9&page=articlesu4.html
I think it should be, because I think the affine parameterization of a light beam should "count wavelengths".
I concur pervect; the affine distance depends on the 4-velocity of the observer.

The age of the universe as measured by two different observers passing each other at speed will depend on their velocities relative to the Surface of Last Scattering, the observer co-moving with the SLS having the greatest age.

Thank you for that link.

Garth
 
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  • #50
Garth said:
I concur pervect;
On second thoughts ...
I will have to consider this further.
the affine distance depends on the 4-velocity of the observer.

The age of the universe as measured by two different observers passing each other at speed will depend on their velocities relative to the Surface of Last Scattering, the observer co-moving with the SLS having the greatest age.
But only in the Einstein conformal frame with a finite age.

I am questionning what happens in the Jordan frame. Perhaps it is only for the "observer co-moving with the SLS" that the universe's age diverges...

The question is:"How is the ruler used in the affine parametrization s \rightarrow \lambda(s) itself calibrated in distant regions?"

Garth
 
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