All models based on a finite age of the universe - are suspect thereof.
How does one 'rule out' infinite age of the universe?
You can't.
Not with infinite big bangs in infinite locations on infinte occasions in an infinite past and future of a universe infinite in all directions and infinite in mass.
That can't be ruled out.
Have people tried to?
Yes. They've tried. With an argument 'if there were infinite stars there'd be no night sky'.
Yes there would be. Various things would prevent light from infinite stars getting everywhere.
And a lot of light doesn't get here anyway.
We're going to see light from the other side of the galactic core - get here??
From an object whose light is blocked by a lot of things? Or severely diluted by distance?
And there's rela --- I'll skip that one for now.
New in cosmology
While that may be so, it is utterly irrelevant here. Planets can only be seen within our galaxy. The present record is 27,000 light years away.
As recently the 1980's there was still no visual proof of planets yet, outside our solar system. Did every star have planets? 50%? 1%? .0001%? Less?
Every possibility was still on the table.
Regarding the big bang - the redshift evidence that it happened - that there was a tremendous explosion a long tme ago - is very very strong evidence.
But only evidence of a very big bang. In this 'locality'.
But that evidence is not evidence of 'the big bang is the universe'.
That's a different animal that might not even exist.
'there can be only one big bang because its the one we're in?'
Hardly.
I got Sonnet 4.5 to generate a version of the quasar density graph. It chose to use a logarithmic scale for comoving density (explicitly correcting for the Hubble expansion) which better reveals the nature of the fall in comoving density after the quasar epoch (2-3 Gyears after the Big Bang). I have to point out that it did not get it right first time but this version does not raise any red flags.
@Optimissed is irrational about the long discarded steady state hypothesis. Look out into the Universe and you find it has changed a lot over time. At the furthest back that we can see, it was a hot, almost perfectly uniform gas! A while after that we see the age when quasars were common - very different to now.
Here are the graphs of quasar frequency and quasar luminosity versus time before the present day. It is interesting that the numbers have been falling for a long time, but have been almost zero in the last billion years.
This is a graph of a universe that is no more "steady state" than a person is from the time they are born to the time they die - we see changes.
At this point, Steady State has only slightly more credibility, than Flat Earth.
Slightly more? Surely not! 
The thing is, I understand the theory and the (very major) objections to the Big Bang. I've been talking to qualified people for 20 years and I know that the Big Bang is no longer credible in their eyes. I don't mean everyone but the intelligent ones do see the problems. How many qualified people are there here for me to talk to? Name one.
You "know" things that are not true.
If asked, virtually all relevant experts would say they accept the reality of the Big Bang. What exactly do you not believe in (stated in objective scientific terms)?
Regardless, one thing that is definitely not true is that the Universe is steady state. The hypothesis has been convincingly falsified since we have had good deep space observations to show the way the Universe has changed.
The reality is that this is a place dedicated to the perpetuation of out of date ideas, where any discussion whatever of potentially real hypotheses is strenuously resisted. An intelligent person could tell this is so, by the absense of logical and evidence based discussion. Elroch doesn't understand what is meant by steady state, so I'll explain. It's quite simple and there are many potential steady state possibilities, just as no-one actually knows what another person means my "The Big Bang", since the concept carries many hypothetical variations.
Steady State refers to a universal state where there is no clear beginning. In fact, it would be impossible to tell if there were a beginning, since we have no perception of areas of the universe which undoubtedly exist, over the horizon. Steady State doesn't imply "no change".
There isn't any point looking at AI. AI, the other week, told me that something I was enquiring about doesn't exist, on two separate occasions regarding two separate objects, so it's hardly likely to provide any insight on this subject.
You "know" things that are not true.
If asked, virtually all relevant experts would say they accept the reality of the Big Bang. What exactly do you not believe in (stated in objective scientific terms)?
Regardless, one thing that is definitely not true is that the Universe is steady state. The hypothesis has been convincingly falsified since we have had good deep space observations to show the way the Universe has changed.
The idea that all the mass of the universe originated at one point in space and time was the basis of the initial BBT. (Big Bang Hypothesis). Attempts were made to mathematically model it and it was found to be impossible. Other ideas have the BB originating at many different points. That's getting very close to steady state. The main problem is that we do not know what's over the horizon and we can only surmise.
As much as anything, I'm talking about the deficiencies of the BB. It doesn't explain accelerated expansion or gravity. It doesn't explain formation of new stars, which this discussion referred to. All it does is expect us to believe in an incredibly unwieldy idea. There are some still accepting of it (BBT) but they are firmly rooted next to the dinosaur house.
There is no such belief "that all the mass of the universe originated at one point in space and time".
This loose misunderstanding is at least 50 years out of date.
It is accepted that known physics definitely breaks down at the Planck energy, so there is no extrapolation of the Big Bang past this. (In addition, there are certainly things that are not understood about the physics at energies between that and the range where we have good understanding - say up to about 10^15 Kelvin).
The picture of almost perfectly homogenous expansion with decreasing temperature and density is however a solid conclusion from when the temperature was 10^15 Kelvin. It is also a pretty confident hypothesis that the same description is true to much higher energies, with new physics having a similar character to known physics (new particles, new bosonic forces).
There is also a lot of confidence in the additional hypothesis of an inflationary epoch at energies well beyond known physics, as a plausible and elegant explanation of the extreme (and very slightly imperfect) homogoeneity and isotropy of the Big Bang.
The actual hypothesis that extends this further is that there was a quantum gravity epoch that preceded the Big Bang. This is very poorly understood because all physics that we know is pretty irrelevant, and the physics that is needed is not known.
No singularity is hypothesised. No infinite density point (the Planck density is the limit).
Exactly. They have moved right away from the infinite density postulation, which was the initial basis of the BBT. When I was talking to ppl, those with PhDs in the subject were more resistant to criticism of it, for what should be obvious reasons. Those in an advanced stage of their physics PhDs were the most open. There's a big investment in what people have been taught to think. 20 years ago, I predicted that they will cling to the BBT as a holding hypothesis and that it will only be overthrown around 2040. There's a lot of resistance to a proper rethink.
The graphs of quasars apply to specific regions of space. We don't have a full picture.
Exactly. They have moved right away from the infinite density postulation,
Firstly, the Big Bang theory is about the expansion of the Universe from when it was tiny and hot, just just the first microsecond. All the way from more than 10^15 Kelvin down to a few thousand degrees at the time of last scattering (at 380,000 years).
While a true singularity was never a formal part of the Big Bang (rather an excessive extrapolation of the simplest model), the way in which it wasn't was made clear over half a century ago. Indeed Wheeler provided the way to do so in 1955 by his observation that at very small scales, space-time loses its regularity, and is replaced by some sort of foam-like structure.
It was in the 1970s (half a century ago) that Hawking and others explored the nature of the early Big Bang, finding that quantum gravity theories would remove the need for a singularity. I recall Hawking described it in "A brief history of time" with the analogy of the North pole of the Earth - a singularity of the co-ordinates of latitude and longitude, but actually smooth.
What has happened is that your understanding of the Big Bang theory is half a century out of date, and you are arguing against your own misunderstanding.
Did Hawking backtrack on this? Or did I misunderstand both books?
It's interesting to explore this. If you ignore inflation, the present day observable Universe would be about 10^10 times wider than a proton at the Planck time. But with inflation you could certainly fit it all in the size of a proton at those energies - for reasons I am not familiar with, it is believed that inflation caused an expansion by an enormous factor of 10^60 or so.
I don't know why Hawking picked the size of a proton - maybe he was using it loosely as the smallest thing that has a known finite diameter (unlike an electron)?
It's worth emphasising that there is an crucial distinction between the size of a proton (a small, finite size) and a singularity (exactly zero size). A proton is not a singularity or a point at LHC energies. A proton diameter is quite big at the much higher energies at the Planck time. The diameter of a proton is about 10^20 Planck lengths - that's the distance that you can resolve at that energy.
In any case, those ideas of quantum fluctuations creating the Universe are speculation rather than being part of the accepted model.
Did Hawking backtrack on this? Or did I misunderstand both books?
One thing to realise about Hawking .... he was a mathematician who was interested in cosmology. He was special, since, due to his determination and intelligence, he survived well past his life expectancy. One thing, however, was that he was very much attracted to off the wall ideas. This attraction was a form of attention seeking, so that his judgement was never to be trusted, on non-mathematical subjects. He was attracted to ideas for which there was no evidence and to flights of fancy.
If matter and space can appear spontaneously, are mutually entangled and have a half life, but space has the property of expanding and will disappear along with the entangled matter when they reach end of life, we have all we need for the spontaneous creation of spiral nebulae.
I know it's believed that the universe originated as a hot state but that isn't proven. It fits mathematical models no better than any other hypothesis based on the topography of the universe. It's rather weak, since where did the original heat come from? Heat is normally created due to increasing density.
It's easy to pick aspects of this and ask for proof but that isn't the point, since the BBT isn't proven either. To many theorists, the BBT is the less plausible.
@Optimissed is irrational about the long discarded steady state hypothesis. Look out into the Universe and you find it has changed a lot over time. At the furthest back that we can see, it was a hot, almost perfectly uniform gas! A while after that we see the age when quasars were common - very different to now.
Here are the graphs of quasar frequency and quasar luminosity versus time before the present day. It is interesting that the numbers have been falling for a long time, but have been almost zero in the last billion years.
This is a graph of a universe that is no more "steady state" than a person is from the time they are born to the time they die - we see changes.
At this point, Steady State has only slightly more credibility, than Flat Earth.