[Bogie_smiles (OP)]

Reply #100

If you think of it most of the current knowledge points to a very high energy density in the beginning. The way stars made us is a direct result from transformations needing heat aka 'kinetic motion'. It doesn't really discuss a geometry although we presume there to be needed some sort of confinement for it to exist, well, at least I do

I agree with your take on the required “confinement” or energy density containment of extreme density, and I think most people think of the Big Bang as being associated with conditions akin to a super massive black hole of proportions sufficient to contain the hot dense energy ball that BBT/Inflation features.

But without 'particles' transferring this 'heat' those initial conditions becomes one of pressure, which then links to Einsteins stress energy tensor. It's interesting

And a very high energy density is also about heat.
=

Again you seem to have thought it through, and concluded that unless there were particles present, the containment of the heat seems problematic. You point out that the equivalent pressure may be provided by the EFE stress tenor, and I’m not sharp enough to comment.

However, if the concept of a massive black hole preceding the Big Bang has any merit, such a crunch could be accumulated from galactic matter and stellar/galactic black holes which could feature dense particle containment and heat transfer.

And if we want to add to that we can consider the homogeneous isotropic universe we find around us. A 'Big Bang' whatever that means is not a centered source, situated at some 'middle of the universe'. In a way it never stopped as every 'point' of this universe still expands. No center to it, and the proof of that lies in astronomical observations of 'early light', being all around us. I can't see any other way to understand it myself.

Great minds have pondered it for a long time, and the consensus BBT/Inflation cosmology is bound to evolve as the scientific community advances our understanding.

[Bill S]

There are two very good questions you can ask
What makes a vacuum

Would that be an "absolute" vacuum, which must be nothing; or the sort that fills our Universe, which is obviously something?

[yor_on]

 Bill " Presumably, you mean the beginning of our "observable" Universe; not the beginning of everything; before which there would have been "nothing"."

It's about 'falsifying'. What it means to me is that it has to be testable, you need to probe it to know. What was 'before' is not yet probe-able, and that places it in meta physics. A pure nothing is still interesting though. If you are a fan of waves one might presume that quenching them, even virtually, might 'produce that sort of of vacuum, but I do think HUP will make problems even then, as well as the second and third law of entropy which state that a zero temperature isn't reachable .

"The Third Law states, “The entropy of a perfect crystal is zero when the temperature of the crystal is equal to absolute zero (0 K).” According to Purdue University, “The crystal must be perfect, or else there will be some inherent disorder. It also must be at 0 K; otherwise there will be thermal motion within the crystal, which leads to disorder.”   

 Siabal Mitra, a professor of physics at Missouri State University, provides another implication of this law. “One version of the Third Law states that it would require an infinite number of steps to reach absolute zero, which means you will never get there. If you could get to absolute zero, it would violate the Second Law, because if you had a heat sink at absolute zero, then you could build a machine that was 100 percent efficient.”   "

And here is a mathematical proof of the third law
https://www.nature.com/articles/ncomms14538

" The Second Law indicates that thermodynamic processes, i.e., processes that involve the transfer or conversion of heat energy, are irreversible because they all result in an increase in entropy. Perhaps one of the most consequential implications of the Second Law, according to Mitra, is that it gives us the thermodynamic arrow of time.

In theory, some interactions, such as collisions of rigid bodies or certain chemical reactions, look the same whether they are run forward or backward. In practice, however, all exchanges of energy are subject to inefficiencies, such as friction and radiative heat loss, which increase the entropy of the system being observed. Therefore, because there is no such thing as a perfectly reversible process, if someone asks what is the direction of time, we can answer with confidence that time always flows in the direction of increasing entropy. "

If that isn't reachable then there must be 'energy' with the possibility of increasing entropy and  HUP is yet another way of looking at it. So I'm not sure how to reach that state? You could also possibly define a vacuum without time, as we both know that time is presumed to be a symmetry of sorts, in physics and mathematics you theoretically can 'wind time backwards', even though there are no proofs of the same existing practically. So stopping time stops fluctuations but how, will, or can, we measure/reach such a state?

[Bill S]

It's about 'falsifying'. What it means to me is that it has to be testable, you need to probe it to know.

OK.  If I express the opinion that there can never have been “nothing”; that could be falsified if someone could produce an example of “something from nothing”. Takers are a rarity.

What was 'before' is not yet probe-able, and that places it in meta physics.

True, but surely, we should not simply suspend our logical faculties when considering possibilities.  After all, we are talking about science, not religion. 

A pure nothing is still interesting though.

So it would seem.
 

[yor_on]

meta physics isn't suspending ones logical faculties Bill. Both you and me do it, but it's just not as straightforward. One example of it might be to argue that if indeed a vacuum is something, shouldn't there be something it exist in? Both questions are interesting :) but not answerable until someone find that way to probe them by experiments and mathematics. If the universe would be a mathematical space then I don't think it needs anything except a logic f.ex. Which of course is a very large step away from any normal expectation.

[Bill S]

meta physics isn't suspending ones logical faculties Bill.

I certainly didn’t intend giving the impression I thought that was the case.  I was making the point that just because something is “not yet probe-able”, we should, perhaps, not treat it as though it were not worthy of logical thought/reasoning.  Your response suggests that our thinking is much the same there.

[Bogie_smiles (OP)]

Reply #106

Elsewhere, I have explained why I would normally use “cosmos” in this context; but “Universe” seems OK.  I would have to include one serious proviso, but this is neither the time nor place to climb into my soap box about eternity/infinity.

Reading back through the thread, I think it is time for Bill S to tell what he meant about preferring to use the word “cosmos” instead of “universe”, and also, why he balked at “climbing on his soap box about eternity/infinity”.

[Bill S]

Reading back through the thread, I think it is time for Bill S to tell what he meant about preferring to use the word “cosmos” instead of “universe”, and also, why he balked at “climbing on his soap box about eternity/infinity”.

It’s not a question of preferring one term to another. As noted above, I’ve explained elsewhere that I generally follow John Gribbin’s suggestion; which I summarised as:

Cosmos = everything that exists, or can exist.
Universe = our (in principle) observable portion of spacetime and its contents.
universe = any other universe that may, or may not, exist.
 
This is a quote from Gribben’s book, “Companion to the Cosmos”. 

    “Universe   With the capital “U”, the term used for everything that we can ever have knowledge of, the entire span of space and time accessible to our instruments, now and in the future.  This may seem like a fairly comprehensive definition, and in the past has traditionally been regarded as synonymous with the entirety of everything that exists.  But the development of ideas such as inflation suggests that there may be something else beyond the boundaries of the observable Universe - regions of space and time that are unobservable in principle, not just because light from them has not yet had time to reach us, or because our telescopes are not sensitive enough to detect their light.  This has led to some ambiguity in the use of the term “Universe”.  Some people restrict it to the observable Universe, while others argue that it should be used to refer to all of space and time.  In this book, we use “Universe” as the name for our own expanding bubble of spacetime, everything that is in principle visible to our telescopes, if we wait long enough for the light to arrive.  We suggest that the term “Cosmos” can be used to refer to the entirety of space and time, within which (if the inflationary scenario is correct) there may be an indefinitely large number of other expanding bubbles of spacetime, other universes with which we can never communicate.”

I hope this clarifies things.

The “soapbox” thing was because I thought it could derail the thread.

[Bogie_smiles (OP)]

Reply #108

It’s not a question of preferring one term to another. As noted above, I’ve explained elsewhere that I generally follow John Gribbin’s suggestion; which I summarised as:

Cosmos = everything that exists, or can exist.
Universe = our (in principle) observable portion of spacetime and its contents.
universe = any other universe that may, or may not, exist.

This is a quote from Gribben’s book, “Companion to the Cosmos”. 

    “Universe   With the capital “U”, the term used for everything that we can ever have knowledge of, the entire span of space and time accessible to our instruments, now and in the future.  This may seem like a fairly comprehensive definition, and in the past has traditionally been regarded as synonymous with the entirety of everything that exists.  But the development of ideas such as inflation suggests that there may be something else beyond the boundaries of the observable Universe - regions of space and time that are unobservable in principle, not just because light from them has not yet had time to reach us, or because our telescopes are not sensitive enough to detect their light.  This has led to some ambiguity in the use of the term “Universe”.  Some people restrict it to the observable Universe, while others argue that it should be used to refer to all of space and time.  In this book, we use “Universe” as the name for our own expanding bubble of spacetime, everything that is in principle visible to our telescopes, if we wait long enough for the light to arrive.  We suggest that the term “Cosmos” can be used to refer to the entirety of space and time, within which (if the inflationary scenario is correct) there may be an indefinitely large number of other expanding bubbles of spacetime, other universes with which we can never communicate.”

I hope this clarifies things.

It does. Gribbin really nails the situation in a way that makes a lot of sense and allows for making some distinctions for various scenarios. In the quote you provided from Gribben’s book, “Companion to the Cosmos”, the last sentence typifies its universal applicability when it refers to the cosmos as “the entirety of space and time, within which there may be an indefinitely large number of other expanding bubbles of spacetime, and other universes with which we can never communicate.”

We have to appreciate how all encompassing that makes the word Cosmos in regard to its applicability to any and all of the various possible models of cosmology.

It can apply to our observable universe and to every reputable model of cosmology that has to be consistent with what we can and do observe. That means it satisfies Big Bang Theory with Inflation Theory, which includes General Relativity, Spacetime, and the expanding universe, and accelerating expansion for that matter. It covers any model that invokes the Cosmological Principle, and it accommodates the cyclical models too. It accommodates Guth’s Inflation Theory with the false vacuum, and it accommodates Quantum Mechanics with all of its Interpretations, meaning it works for Quantum Physics, including Quantum Field Theory and the nucleating bubbles of the false vacuum, and Quantum Chromodynamics, and any QM associated model. It even satisfies the requirements of String Theory with its infinite multiple universes and dimensions. And not the least of which, it applies to any version of a Steady State Theory which go beyond those that invoke the cosmological principle and vacuum energy density to also invoke the Perfect Cosmological Principle that specifies that the universe is homogeneous and isotropic, not only in space, but in space and time, as mentioned in the OP.

Still, I like the versatility of the definition offered in this thread which has the same range of applicability as Gribbin’s full scope definition, but that also has something that I am going for that might not have been necessary to Gribbin in the context of his book. In the context of this thread that starts out about “nothingness” I was interested in making “universe” the antithesis of “nothingness”, and so universe is everything that nothingness is not.

Nothingness: No space, no time, no energy, and no potential for any space, time or energy.
Universe: There is just one universe and it encompasses all there is, all matter, energy, everything, in one infinite and eternal presence, that had no beginning and will have no end, i.e., the universe has always existed, and has always been governed by the same set of invariant natural laws.

Edit Note: Thank you for your participation in this thread. I have linked the content of it to my on-going thread in the “On the Lighter Side” forum category, in the New Theories Sub-forum and to my thread, “If there was one Big Bang event, why not multiple Big Bang events”: https://www.thenakedscientists.com/forum/index.php?topic=70348.msg548939#msg548939

[Zer0]

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[Bill S]

I'm mystified by #109.  Is it a link to facebook?

[Bogie_smiles (OP)]

I'm mystified by #109.  Is it a link to facebook?

Actually Zero was being clever. The post is close to nothingness, but does consist of a single period in a light color, maybe white or grey.

[Bill S]

Too smart for me.

I put it in my search bar and ended up here:
https://www.facebook.com/ArtCtrlDel/posts/%221n73ll1g3nc3-15-7h3-4b1l17y-70/1001986609936346/