Big Bang & Infinite Universe: Evidence & Discrepancies

[Rupert Young]

Following on from this thread. If the universe is infinite and was at the time of the big bang does that not mean that the size and contents was infinite? In other words at the BB there was already infinite amount of galaxies.

I had understood that at, or just after, the BB the mass of the universe was in a very small space.

If so, then these two theories, the BB and the infinite universe, seem mutually exclusive, and we can discount one of them if we have convincing evidence for the other. Or is our confidence in both of these so poor that we cannot discount either?

Or am I missing something?

 

[rootone]

BBT is a theory applicable to the observable universe, which is not infinite.
The entire universe may or may not be infinite and as far as I know, BBT doesn't have a lot to say about it.

 

[Bandersnatch]

Just to expand a bit on rootone's post: Whenever you hear about the universe at some very early time in its history being the size of <whatever>, it means that what we see now as the observable universe was compressed in such a volume. It does not mean the totality of the universe, or even anything at all that's currently farther than the observable radius.

 

[phinds]

Following on from this thread. If the universe is infinite and was at the time of the big bang does that not mean that the size and contents was infinite? In other words at the BB there was already infinite amount of galaxies.

There would have been an infinite amount of matter/energy, but there would not have been any galaxies. They came later.

I had understood that at, or just after, the BB the mass of the universe was in a very small space.

The OBSERVABLE universe, as has been pointed out, was in a very small space. "the universe" may or may not have been.

If so, then these two theories, the BB and the infinite universe, seem mutually exclusive, and we can discount one of them if we have convincing evidence for the other. Or is our confidence in both of these so poor that we cannot discount either?

Or am I missing something?

Yes, you're missing several things. See above.

EDIT: By the way, most of us have similar confusion when we first start learning this stuff. It IS confusing.

 

[Chronos]

Yes, BBT tells us nothing about the size of the universe, only the observable universe. Unless otherwise specifically stated, cosmologists use these terms interchangably because 'everybody knows' we are only causally connected to the observable universe. It is entirely likely we will never know with any certainty if there is more to it than our causal patch

 

[bcrowell]

Following on from this thread. If the universe is infinite and was at the time of the big bang does that not mean that the size and contents was infinite?

I'm not sure from what you wrote whether you're under the impression that it's been established that the universe is infinite or not. As discussed in the thread you linked to, the spatial curvature of the universe is within error bars of zero, so we don't know whether it's positive or negative, and therefore we don't know whether it's infinite or finite.

I had understood that at, or just after, the BB the mass of the universe was in a very small space.

No, the big bang was not an explosion that occurred in one region of space. It occurred everywhere at once.

If so, then these two theories, the BB and the infinite universe, seem mutually exclusive, and we can discount one of them if we have convincing evidence for the other. Or is our confidence in both of these so poor that we cannot discount either?

Or am I missing something?

Yes, you're missing the fact that the big bang was not an explosion that occurred in one region of space.

 

[ohwilleke]

I would be inclined to say that the statement "the universe is infinite" when using the word "universe" to refer to something beyond the observable universe aka our causal patch, is a misleading use of the term "universe" that confuses people by using it in a manner different from its common usage in science. For the statement to be non-misleading one would need a specifier such as "the universe, including but not limited to the observable universe", although I'm sure that one could come up with something less clunky. While "universe" may have originally been a term meaning absolute everything that exists, has existed or will exist whether or not it can be observed, decades of usage have confined it to the narrower meaning of events causally connected to the Big Bang.

The only affirmative evidence for the existence of anything outside the finite universe narrowly defined as is customary is evidence of "Dark Flow" which is apparently doubtful empirically, although a recent post on LQC at Physics Forums discusses another subtle other way that something pre-Inflation and perhaps pre-Big Bang could be observable in the cosmic microwave background.

 

[bapowell]

The only affirmative evidence for the existence of anything outside the finite universe narrowly defined as is customary is evidence of "Dark Flow" which is apparently doubtful empirically, although a recent post on LQC at Physics Forums discusses another subtle other way that something pre-Inflation and perhaps pre-Big Bang could be observable in the cosmic microwave background.

What about superhorizon CMB temperature and polarization correlations?

 

[bcrowell]

I would be inclined to say that the statement "the universe is infinite" when using the word "universe" to refer to something beyond the observable universe aka our causal patch, is a misleading use of the term "universe" that confuses people by using it in a manner different from its common usage in science.

AFAIK it's the other way around. The common usage in science is that "universe" refers to the entire universe. Using it to refer to the observable universe is a common solecism among laypeople.

 

[marcus]

AFAIK it's the other way around. The common usage in science is that "universe" refers to the entire universe. Using it to refer to the observable universe is a common solecism among laypeople.

Right. Judging from my experience with astro courses at UC Berkeley, in an academic setting you distinguish carefully between the universe (which is what the standard model cosmos represents) and the currently observable portion of it---the "observable universe".

I would expect that anyone who has taken a college course in astronomy that included cosmology, or had much contact with professional astronomers, would be used to making the distinction. The "observable universe" is not the universe. As you suggest, laypeople get confused about this, and it's really unfortunate because it leads to a lot of misunderstanding.

In comoving distance terms, the radius of the observable region is currently around 46 billion LY and it is increasing. As I recall according to the standard (LCDM) cosmic model it is expected to level out at around 63 billion LY. That is in comoving terms---it will include matter/galaxies that are NOW 63 billion LY from us. The distance then will be much greater. Our "causal patch" (as some people like to say) is steadily expanding day by day to include more matter.

The standard cosmic model does not have a fixed boundary, it does not refer to today's "causal patch". One couldn't do physics if one were artificially limited to this moment's "causal patch". It would be arbitrary, absurd, and unnecessarily complicated. The differential equation that models the universe, models a whole universe.

 

[marcus]

... using the word "universe" to refer to something beyond the observable universe aka our causal patch, is a misleading use of the term "universe" that confuses people by using it in a manner different from its common usage in science.
...

Ohwilleke you astonish me! Where do you get your idea of "common usage"? Can you link to some professional cosmology literature where the authors don't make the distinction between observable universe and the standard LCDM cosmos?

In my experience which is of course limited---not a professional researcher just a longtime interested cosmology watcher---I don't know of any professional who confuses them. The common usage in cosmology for the observable universe is "observable universe". One is careful to make the distinction. Can you link to some professional literature with a different usage?

==quote==
For the statement to be non-misleading one would need a specifier such as "the universe, including but not limited to the observable universe", although I'm sure that one could come up with something less clunky.
==endquote==
Sorry. You have your shoes on the wrong feet. We already have a non-clunky "specifier". It is the word "observable". Universe refers to the whole thing. Observable universe refers to the observable region. There are lower-bound estimates of how much larger the whole universe is. One can infer that it is much larger than the currently observable region, based on upper-bound measurements of the spatial curvature.==quote==
decades of usage have confined it to the narrower meaning of events causally connected to the Big Bang.
==endquote==
I don't understand. What do you mean by "Big Bang"? Do you picture it as only involving space and material that gave rise to our currently observable portion. Brian Powell had a (rather brief) comment about that.

 

[bcrowell]

While "universe" may have originally been a term meaning absolute everything that exists, has existed or will exist whether or not it can be observed, decades of usage have confined it to the narrower meaning of events causally connected to the Big Bang.

You're comparing two things:

(a) "everything that exists, has existed or will exist whether or not it can be observed"

(b) "events causally connected to the Big Bang"

But these are the same thing, contrary to your assertion that b is a subset of a. There aren't events that aren't causally connected to the big bang.

 

[marcus]

... It is entirely likely we will never know with any certainty if there is more to it than our causal patch

Chronos, I can't make logical sense of this statement. When I try to give a definite meaning to your words it seems to be a non sequitur.

"our causal patch" has to mean something definite, so let's say it means our causal patch as of August 2015.

In order to "know with certainty" that that set of matter etc. is NOT the whole shebang all we need to do is WAIT. If for example the CMB continues to shine it will be coming from more distant matter. if the CMB sky continues to look about the same, apart from increasing redshift, that will indicate our observable universe is larger than the 2015 version and includes new matter that will be having a causal effect on us for the first time. This will prove there is in fact "more to the universe" than our August 2015 observable region or, as you say, "causal patch".

Conversely if there is NOT more than August 2015 observable region, then in time we will discover that to be the case, e.g. as when the CMB abruptly goes out.

 

[Chronos]

I use the term in the customary sense: "A causal patch is a region of spacetime connected within the relativistic framework of causality (causal light cones)." [wiki]. As you know, at a redshift beyond about z=1.7 [ a proper distance now of around 15 Gly], photons emitted by objects today will never reach us. Given the CMB is at a proper distance now of around 45 Gly, there are vast expanses over which photons have never and will never be able to reach us, no matter how long we wait. Which means what you see is what you get in the distant universe. No hitherto unviewable regions of deep space will ever suddenly pop into view. We are causally disconnected from such regions.

 

[marcus]

...Given the CMB is at a proper distance now of around 45 Gly, ... Which means what you see is what you get in the distant universe. No hitherto unviewable regions of deep space will ever suddenly pop into view. We are causally disconnected from such regions.

Matter that is today at 47 Gly will (hitherto unviewable) gradually come into view. Matter that is today 50 Gly from us will (hitherto unviewable by us) gradually come into view.
this will take a very long time but according to the standard LCDM cosmic model it will happen. I can find the future times for you.

It sounds from what you are saying that you did not realize this, which would be surprising (knowing you) after so much discussion. It is simply untrue that "what we see (now) is all we eventually get" of the distant universe. But maybe I don't understand what you are saying.

There certainly is a limit to the projected increase (in comoving distance terms ) of the observable amount of matter, the observable region . But 50 Gly is nowhere near that limit!

 

[Chronos]

How does that square with the Davis and Lineweaver claim we will never view photons emitted today at a distance in excess of z=1.7? I concede I may be confused if that claim has been rubutted.

 

[Bandersnatch]

How does that square with the Davis and Lineweaver claim we will never view photons emitted today at a distance in excess of z=1.7? I concede I may be confused if that claim has been rubutted.

Take a look at the spacetime diagram from the L&D paper:

At present, the distance to the event horizon (where it intersects with the 'now' line) is 17.3 Gly. This means that, as you say, light emitted from those galaxies will eventually reach us at t=∞, while nothing beyond ever will.

However, the even horizon extends to our past as well. Light signals that were emitted in the past whose lightcones lie within the event horizon will also reach us.
For example, if you look at light emitted at recombination by objects that are now at 63 Gly, their light will be now passing the 17.3 Gly point marking the present event horizon distance, will join the light emitted there presently, and reach us at infinity.

I've found this version of the above graph at physics.stackexchange:

It's got the advantage of using a time scale more intuitive for non-cosmologists, and including lines of constant recession velocity.
More details here: http://physics.stackexchange.com/questions/60519/can-space-expand-with-unlimited-speed
One can trace a signal emitted at any time in the past, and observe how it passes the consecutive regions of superluminal recession rates.

Keep in mind that both graphs use co-moving distances, so the object presently at 63 Gly whose light we'll be able to observe at t=∞ emitted the signal at much closer proper distance (at the time) and will have receeded rather quite farther than that (∞) by the time it reaches us.

 

[marcus]

Nice! Such a perfect job of patient clear explaining that I should know better than to say a word--just distracts from the flow of understanding. But can't resist pasting in Jorrie's default table you get when you open his table&graph-making calculator, with the particle horizon column added. It shows that 63 Gly (comoving) being approached as a limit, in the particle horizon column in the last row. The scale factor in that last row is a = 100 so comoving (nearly) 63 corresponds to proper (nearly) 6300 Gly at that time, which is what you see.
$${\scriptsize\begin{array}{|c|c|c|c|c|c|}\hline R_{0} (Gly) & R_{\infty} (Gly) & S_{eq} & H_{0} & \Omega_\Lambda & \Omega_m\\ \hline 14.4&17.3&3400&67.9&0.693&0.307\\ \hline \end{array}}$$ $${\scriptsize\begin{array}{|r|r|r|r|r|r|r|r|r|r|r|r|r|r|r|r|} \hline a=1/S&S&T (Gy)&R (Gly)&D_{now} (Gly)&D_{then}(Gly)&D_{hor}(Gly)&D_{par}(Gly)&V_{now} (c)&V_{then} (c) \\ \hline 0.001&1090.000&0.0004&0.0006&45.332&0.042&0.057&0.001&3.15&66.18\\ \hline 0.003&339.773&0.0025&0.0040&44.184&0.130&0.179&0.006&3.07&32.87\\ \hline 0.009&105.913&0.0153&0.0235&42.012&0.397&0.552&0.040&2.92&16.90\\ \hline 0.030&33.015&0.0902&0.1363&38.052&1.153&1.652&0.249&2.64&8.45\\ \hline 0.097&10.291&0.5223&0.7851&30.918&3.004&4.606&1.491&2.15&3.83\\ \hline 0.312&3.208&2.9777&4.3736&18.248&5.688&10.827&8.733&1.27&1.30\\ \hline 1.000&1.000&13.7872&14.3999&0.000&0.000&16.472&46.279&0.00&0.00\\ \hline 3.208&0.312&32.8849&17.1849&11.118&35.666&17.225&184.083&0.77&2.08\\ \hline 7.580&0.132&47.7251&17.2911&14.219&107.786&17.291&458.476&0.99&6.23\\ \hline 17.911&0.056&62.5981&17.2993&15.536&278.256&17.299&1106.893&1.08&16.08\\ \hline 42.321&0.024&77.4737&17.2998&16.093&681.061&17.300&2639.026&1.12&39.37\\ \hline 100.000&0.010&92.3494&17.2999&16.328&1632.838&17.300&6259.262&1.13&94.38\\ \hline \end{array}}$$
http://www.einsteins-theory-of-relativity-4engineers.com/LightCone7/LightCone.html
Open the "column definition and selection" menu to add the particle horizon column to the default table.

 

[Rupert Young]

No, the big bang was not an explosion that occurred in one region of space. It occurred everywhere at once.

Yes, you're missing the fact that the big bang was not an explosion that occurred in one region of space.

Whoah, if that is the case then yes I have fundamentally misunderstood the big bang thing.

As it says here,

Since Georges Lemaître first noted, in 1927, that an expanding universe might be traced back in time to an originating single point, scientists have built on his idea of cosmic expansion.

I had understood that the mass of the universe was in a single point at the BB and that since then it has been moving away from that point, in all directions, and coalescing into galaxies.

Are you saying that at the BB all matter came into existence in many different places; essentially where it is now, if not for gravity moving matter around, and also expansion?

If the universe is infinite then matter appeared everywhere instantly in an infinitely sized universe; then the matter coalesced into galaxies.

If the universe is finite then matter appeared everywhere instantly in an enormous finitely sized space; then the matter coalesced into galaxies.

 

[Bandersnatch]

If the universe is infinite then matter appeared everywhere instantly in an infinitely sized universe; then the matter coalesced into galaxies.

If the universe is finite then matter appeared everywhere instantly in an enormous finitely sized space; then the matter coalesced into galaxies.

That's correct.
Imagining that everything remains where it is at all times (relative positions don't change), and only distances grow with time is a good way to visualise BB. (It might help ease oneself into understanding co-moving coordinates later on)
With the caveat that the expansion means that back then everything was closer together, and if you extrapolate backwards far enough the 'closer together' becomes 'infinitely closer together' - so even in an infinite universe you can say that everything was infinitely close (which is unlikely to be a real state in the history of the universe - this particular prediction is likely unphysical).

In my opinion it is really better not to look at BB from 'the point of origin' onwards to the present time and beyond - it brings about singularities, energy popping up from who knows where and other questions that have more to do with personal preference and speculation that with describing what the model does.

I think it is better to start with now, and then look backwards or forwards in time, and when the model ends up with singularities just stop using it.
This way you don't worry about where stuff came from, but can appreciate the very simple predictions: that earlier in time everything was just where it is now (relative positions), filling the whole of available space, however large, but all closer together, and in the future it will get further apart.

Then the question of whether the universe is finite or infinite becomes secondary - the model works for both cases.

 

[phinds]

Bandersnatch, I think that's an excellent post but I do have to take issue with your saying

... if you extrapolate backwards far enough the 'closer together' becomes 'infinitely closer together'

. I think that's wrong. Counting the presumed inflation in the first trivial amount of time, as far as we know, the backward extrapolation from today can only be by a factor of something like 10^60 and while that is a huge amount, it is basically zero when compared to infinity.

 

[Bandersnatch]

Hi phinds. Can you elaborate a bit more? I was under the impression that the BB and inflation were separate, the latter intended to supplement BB at very early times. The BB itself should lead to a singularity with infinite density.

 

[phinds]

Hi phinds. Can you elaborate a bit more? I was under the impression that the BB and inflation were separate, the latter intended to supplement BB at very early times. The BB itself should lead to a singularity with infinite density.

My understanding is that if you use math and ignore physics then yes you get that. If you use physics what you have to say is that the BB as we know it started at one Plank time after the singularity (and this is what I was extrapolating back to with my approximate 10^60 factor) and that's ALL we can say because the model breaks down (again, thinking in terms of physics, not math) if you extrapolate back to t=0 rather than extrapolating back to "t=0 plus one Plank time".

So with math your statement is correct but with physics it's not. That's my take on the situation anyway.

 

[Bandersnatch]

Fair enough. So we may say that it breaks down even before infinite density.
Not that I know anything about those regimes.

 

[phinds]

Fair enough. So we may say that it breaks down even before infinite density.
Not that I know anything about those regimes.

I'm not sure that "breaks down before the singularity" is quite right either. Just "breaks down mathematically at the singularity". In any case, I think the best way to look at it was posted by one of our smarter members:

I think it is better to start with now, and then look backwards or forwards in time, and when the model ends up with singularities just stop using it.

 

[Chronos]

I'm still stuck on the idea we can never, in principle, view photons emitted from beyond the surface of last scattering. We can only view object [stars and galaxies] that formed between us and the CMB - there are no objects that formed beyond the CMB. I agree remote galaxies in this region that are currently unobservable may someday become observable by virtue of photons emitted long ago crossing into our Hubble sphere, although I temper that with the notion accelerated expansion will someday redshift sufficiently remote objects beyond detectability.

 

[marcus]

I'm still stuck on the idea we can never, in principle, view photons emitted from beyond the surface of last scattering. ..

But there are photons from matter which is beyond today's SoLS which are already on their way to us and are even within 14 Gly of us, making progress towards us. Why shouldn't there be? The matter that constitutes the SoLS changes over time and the SoLS enlarges as there is time for more distant light to come in.

 

[Chronos]

I still am struggling to reconcile all this with, for example, this article https://www.relativitycalculator.com/articles/the_end_of_cosmology/the_end_of_cosmology.html, where it is noted in the illustration on p48 "at the onset of acceleration we see the largest number of galaxies that we ever will".

 

[Bandersnatch]

I still am struggling to reconcile all this with, for example, this article https://www.relativitycalculator.com/articles/the_end_of_cosmology/the_end_of_cosmology.html, where it is noted in the illustration on p48 "at the onset of acceleration we see the largest number of galaxies that we ever will".

I've spent some hours now banging my head against the wall trying to understand what Krauss and Scherrer meant by that statement.
Here's what I managed to figure out, hopefully it makes some sense:

First, in the oft-cited Davis & Lineweaver paper an equivalent statement by Krauss is quoted as an example of 'misconceptions or easily misinterpreted statements in literature':

[13] Krauss, L. M. and Starkman, G. D. 1999, ApJ, 531(1), 22–30, Life, the universe and nothing: Life and death in an ever-expanding universe, “Equating this recession velocity to the speed of light c, one finds the physical distance to the so-called de Sitter horizon... This horizon, is a sphere enclosing a region, outside of which no new information can reach the observer at the center”. This would be true if only applied to empty universes with a cosmological constant - de Sitter universes. However this is not its usage: “the universe became Λ-dominated at about 1/2 its present age. The ‘in principle’ observable region of the Universe has been shrinking ever since. ... Objects more distant than the de Sitter horizon [Hubble Sphere] now will forever remain unobservable.”

Notice the objection by D&L.
This gave me some hope that I'm not entirely misguided in my understanding.
It is, however, unclear whether D&L think the statement is an example of misconception or just an easy to misinterpret one. Taken on the face value it would have to be the former as Hubble sphere is an even horizon only in empty (no matter), lambda-dominated universes, or in the infinite future of universes with matter (such as ours). But I'd give the professional cosmologists who wrote that some more credit.

The original paper available on arxiv provides some context:
Krauss, L. M. and Starkman, G. D., Life, the universe and nothing: Life and death in an ever-expanding universe
In the light of then-recent discoveries of dark energy driving the expansion, the authors estimate that in our universe observable objects beyond our local supercluster will become redshifted beyond detectability (wavelengths longer than the horizon diameter) in a finite time.
They acknowledge that the de-Sitter horizon is not strictly applicable to our universe, but argue that it will become practically equivalent to the actual event horizon in relatively short time.
Since the event horizon in time becomes equivalent to the Hubble sphere, the ability of the observers in the far future to see non-locally bound galaxies can be estimated based on whether or not galaxies stay within the Hubble sphere as the universe evolves.

If we now look at the spacetime graph:

we can see that at the moment of beginning of acceleration (thin horizontal red line) there was the maximum number of galaxies lying within the Hubble sphere (vertical red line - each of the comoving distance vertical lines we may draw on the graph, starting at the origin, is equivalent to the worldlines of consecutively farther galaxies).
Up to that point, galaxies were crossing the Hubble sphere from the 'outside'. From that point on, they are crossing it from the inside.
This fact in itself doesn't mean anything - again, the Hubble sphere is not a horizon in our universe, so the mere fact that a galaxy or an older (e.g. CMBR) signal crosses it doesn't make it unobservable.
However, the point in time where Hubble sphere begins shrinking in comoving distance terms marks a change in the 'fates' of the observability of galaxies in the far future.

It's not a real change, though, since the observability of a signal emitted at any comoving distance is uniquely determined in a given model. It can be seen just by looking at the curve of the actual event horizon - if it's outside, it'll never be observed, if it's within, it'll always be casually connected (even if redshifted beyond detectability).
I see this as a more of a 'what if' scenario: what if the slope of the curve of the Hubble sphere could be held constant at say 5 Gy? Then the far-future observers would see more and more galaxies, forever, no problem. What if it could be held constant at the point of switch from deceleration to acceleration? Then they'd see the amount of galaxies contained within for all time, while the more distant ones (and CMBR) get redshifted beyond observability. What if the curve keeps evolving like it does? They'll be stuck with their local supercluster only.
We're in the latter scenario, so the best possible 'chance' for the future observers to be in a non-desolate universe already passed.

At least that's the best I could come up with. Maybe there's a better reason for using that picture by Krauss, Scherrer and Starkman. Maybe in the popular article it's just a convenient picture to paint the process of galaxies 'escaping', maybe in the paper it's just a shorthand used to make rough estimates. Maybe something else. Far for me to say that I understand the topic better than the authors of either publication.

 

[Chronos]

I have reconciled the statement by Krauss by starting with the particle horizon. It's easy to see that no photon emitted from behind the particle horizon could ever, even in principle, reach us; simply because, by definition, the emitter would be older than the universe. By the same token, the particle horizon is not a point in space, but, a point in time. The universe continues to age as always. In another billion years a billion light years of hitherto unexplored space will become accessible, irrespective of our technological capability. 'New' galaxies may reside in this 'new' space; obviously not because they have been lurking there all along waiting to be exposed, rather, they like all other galaxies coallesce from gas clouds that froze out of the ever retreating CMB surface. Nothing is 'new' in the sense of having always been there, but, merely unobservable - it does not even exist until the particle horizon retreats. All this without falling into the pit of the Hubble sphere. Suffice it to say all photons that originate inside the particle horizon are inevitably destined to enter our Hubble sphere.

 

[JonathanCollins]

There would have been an infinite amount of matter/energy, but there would not have been any galaxies. They came later.

The OBSERVABLE universe, as has been pointed out, was in a very small space. "the universe" may or may not have been.

Yes, you're missing several things. See above.

EDIT: By the way, most of us have similar confusion when we first start learning this stuff. It IS confusing.

It is surely speculative to state that "there would have been an infinite amount of matter/energy"? Since the observable universe is still expanding it cannot be infinite. On the basis that the observable universe is finite its origin is more likely to be finite than infinite.

 

[phinds]

It is surely speculative to state that "there would have been an infinite amount of matter/energy"? Since the observable universe is still expanding it cannot be infinite. On the basis that the observable universe is finite its origin is more likely to be finite than infinite.

Read post #4 and see what I was replying to. You are setting up a strawman that is not what I was replying to and then knocking it down in a way that is correct for the strawman but has nothing to do with what I said

 

[JonathanCollins]

I did read the the post to which you replied. To my understanding your response is stating that at the time of the big bang "there would have been an infinite amount of matter/energy" (which is not known) and "there would not have been any galaxies" (which is very likely from the evidence). Perhaps I have misunderstood your response?

 

[JonathanCollins]

My understanding is that if you use math and ignore physics then yes you get that. If you use physics what you have to say is that the BB as we know it started at one Plank time after the singularity (and this is what I was extrapolating back to with my approximate 10^60 factor) and that's ALL we can say because the model breaks down (again, thinking in terms of physics, not math) if you extrapolate back to t=0 rather than extrapolating back to "t=0 plus one Plank time".

So with math your statement is correct but with physics it's not. That's my take on the situation anyway.

That is also my take. Personally I don't believe maths can necessarily be viewed as a reliable tool for such extreme extrapolations.

 

[phinds]

I did read the the post to which you replied. To my understanding your response is stating that at the time of the big bang "there would have been an infinite amount of matter/energy" (which is not known) and "there would not have been any galaxies" (which is very likely from the evidence). Perhaps I have misunderstood your response?

You are continuing to ignore the difference between the Observable universe and "the universe". Please re-read post #4 again and see exactly what was said and what my response was to exactly what was said.