[esquire]

Is the Universe's initial rapid expansion an exception to the uncertainity principle? Backwards engineering the Universe's age for locality and expansion velocity,  says it is.

Was the initial expansion  of the Universe, faster then the speed of light?

[esquire]

Is the Universe's initial rapid expansion an exception to the uncertainity principle? Backwards engineering the Universe's age for locality and expansion velocity,  says it is.

Was the initial expansion  of the Universe, faster then the speed of light?

Was the Big Bang essentially the creation of a new dimension?

[esquire]

Can  momentum/velocity be a defining parameter for dimensionality?  Would exceeding the speed of light place one in a different separate dimension?

[pensador]

It seems that it all hinges on the laws of quantum mechanics.Where are these laws supposed to have come from? Surely quantum mechanics must be something, or be relate to something; and that something must have predated the “writing” of the laws.  Krauss - a little grudgingly – confesses to not having a clue on this particular issue.  Somehow, he seems to think it doesn’t matter.  Possibly, it doesn’t matter, but I have a feeling that the question as to how – not why – we are here is something that scientists should not relegate to semantic triviality.

This is a bit speculative, but to answer your question; something I have stumbled across recently is SED Stochaistic Electro Dynamics. It attempts to explain the Physics behind Quantum Mechanics, based on the zero point energy of the vacuum. It is a deterministic theory being developed by a number of researchers around the world.

[pensador]

Was the initial expansion  of the Universe, faster then the speed of light?

According to the various inflationary models around yes it was. The inflationary stage of the existing visible universe, speculating might have been the cause of the baryogenesis and hot big bang. The growth of our visible universe is expanding at an accelerating rate. At some stage in the future it could reach inflationary growth rates and again, and who knows another big bang.

[Bill S]

https://www.quantamagazine.org/big-bounce-models-reignite-big-bang-debate-20180131/

I think this is worth a look.  Some of its ideas seem a bit “way-out”, but there’s a lot to think about.

“Imagine there’s just one of these curled-up extra dimensions, a tiny circle found at every point in space. As Graham put it, “At each point in space there’s an extra direction you can go in, a fourth spatial direction, but you can only go a tiny little distance and then you come back to where you started.”

Am I alone in seeing a major snag here?

[CPT ArkAngel]

Was the Big Bang the beginning of the universe?

If what you call "the universe" is everything which is real, then no. The idea that the Big Bang comes from nothing comes from the mixing of three main ideas, each is unproven.

1- There is a vacuum field which has an independent existence of the matter field.
2- Randomness is fundamental.
3- There is a multiverse. (this one is a kind of a consequence of the other 2)

The nothing is not nothing but the vacuum field. Some physicists think that the total energy of the vacuum field is zero. There is an equal amount of positive and negative energy (attraction vs repulsion). But nevertheless, you need constant fluctuations of the field to create matter. The randomness sweeps this necessity under the rug.

The problem is that gravity is not unified with Quantum Mechanics, so this is speculations. From Einstein's point of view, there shouldn't be any vacuum fields in absence of matter. Furthermore, the universe could have no beginning and no end but be finite in energy and space. In fact, this makes more sense if you consider the quantization of the elements which implies some sort of limits on the fields. How such limits could exist in an infinitely large universe? It leads to infinite regressions upon infinite regressions leading to no limit at all...

[Bill S]

 

How such limits could exist in an infinitely large universe? It leads to infinite regressions upon infinite regressions leading to no limit at all...

The ultimate apagoge!

[Bill S]

Some physicists think that the total energy of the vacuum field is zero. There is an equal amount of positive and negative energy

Isn't this conclusion based on the apparent belief that zero net energy and zero total energy are synonymous?
Wouldn't that belief be erroneous?

[CPT ArkAngel]

"How such limits could exist in an infinitely large universe? It leads to infinite regressions upon infinite regressions leading to no limit at all..."

It is not a proof but I invoke Occam's razor. You may add fixed parameters resulting in more fine tuning. Same for your other question. Hi Bill!

[CPT ArkAngel]

To your second question, yes. My point of view is there is no negative energy, there is just inflows and outflows of mass-energy. There is attraction and repulsion but no negative energy. I must stop here because it is just a theory... A last comment: Time and space have asymmetries which generate the structure of matter and space-time. That's how you get only positive energy. Time is the dynamics. Think about the Equivalence Principle.

[Bill S]

Entropy? Heat death? You would need a way of perpetually undoing the increase in entropy AND be consistent with the laws of thermodynamics.

Just a thought about the entropy involved.  although scientists assure us that they can follow the course of the expansion of the Universe backwards to an unimaginably small fraction of a second after the Big Bang, they cannot actually reach it.  It follows, therefore, that at the point at which the “known” history of the Universe starts, the Universe already existed.

Thus, the BB doesn’t explain the “presence” of the Universe.  However, it does seem to indicate that entropy was very low at the start.  Is this the case?

If no “new” matter/energy has been “created” since the BB; it follows that, initially, the entire Universe was compacted into an unimaginably small “space”.   

At the start, the entropy of the Universe must have been at its maximum.  There were few, if any, ways in which the contents could be distributed.  Only when the Universe began to expand would there have been room for possible variations of the state of the quark/gluon plasma, or whatever the composition was.

The “creation” of space lowered the entropy by providing the potential for “work”. 

[pensador]

If no “new” matter/energy has been “created” since the BB; it follows that, initially, the entire Universe was compacted into an unimaginably small “space”.   

No it does not, the Big bang is a model of the visible universe. Space is expanding, and a microscopic volume of space now in a few trillion trillion years will occupy a larger volume of space.

Thus, the BB doesn’t explain the “presence” of the Universe.  However, it does seem to indicate that entropy was very low at the start.  Is this the case?

Entropy of space is tending towards zero as the universe expands. See Penroses ideas. The big bang might repeat itself over and over again in different Aeons.

It follows, therefore, that at the point at which the “known” history of the Universe starts, the Universe already existed.

Why should a universe not already exist.

------------

The HUP does not violate the laws of thermo dynamics because it only borrows energy from the vacuum of space momentarily. The Zero point energy of the vacuum, is theoretically zero. The Casimir effect proves it exists.. It is not beyond the realms of possibility that the inflation of a region of space separated virtual particle pairs from the vacuum of space causing baryogenesis. Not unlike Hawking radiation around Blackholes.

A pop science link to SED, this link got me interested. http://www.calphysics.org/zpe.html It seems that the zero point vacuum energy of space might be behind the HUP the expansion of space how atoms are created, entanglement etc etc. SED has been under development for about 30 years by various theoretical physicists.

[Bill S]

  No it does not, the Big bang is a model of the visible universe. Space is expanding, and a microscopic volume of space now in a few trillion trillion years will occupy a larger volume of space.

Are you saying that about 10^-43s after the BB, the “visible universe” did not occupy “an unimaginably small space”?  If you are not; I struggle to see the relevance of the comment, however correct it might be in itself.

Entropy of space is tending towards zero as the universe expands.

I do my best with entropy.   I thought it was increasing as the Universe expands, but I could have that wrong.

See Penroses ideas. The big bang might repeat itself over and over again in different Aeons.

No argument there, but I don’t see the relevance to the entropy of the nascent Universe.

It follows, therefore, that at the point at which the “known” history of the Universe starts, the Universe already existed.

Why should a universe not already exist.

If my quote suggested that the Universe should not already have existed, it was unintentional.

[pensador]

I do my best with entropy.   I thought it was increasing as the Universe expands, but I could have that wrong

Yes the overall entropy of the universe is increasing. However in space there isnt much there except galaxies. As the universe continues to expand and all the visible galaxies and bits of rock dissappear over your visible horizon you are effectively in an area of space with a very low entropy ie it tends towards zero, because there aint nothing there except zero point energy of the vacuum, which might be what drives the expansion of space.

Are you saying that about 10-43s after the BB, the “visible universe” did not occupy “an unimaginably small space”?  If you are not; I struggle to see the relevance of the comment, however correct it might be in itself.

OK I suspect you are taking the piss But lets say in a volume of space the size of a grapefruit devoid of matter and therefore zero entropy, it starts to expand at speeds not seen before the inflationary stage of the big bang model due to the zero point energy of the vacuum. This expansion is so fast that virtual particles are separated and become real causing baryogenesis and Big Bang nucleo synthesis the universe as we know it etc Until the next Aeon
 

No argument there, but I don’t see the relevance to the entropy of the nascent Universe.

https://en.wikipedia.org/wiki/Conformal_cyclic_cosmology

[pensador]

At the start, the entropy of the Universe must have been at its maximum.  There were few, if any, ways in which the contents could be distributed.  Only when the Universe began to expand would there have been room for possible variations of the state of the quark/gluon plasma, or whatever the composition was.

The “creation” of space lowered the entropy by providing the potential for “work”. 

You are agreeing with me here I think. Expansion of space reduces the entropy locally in that region of space.

[Bill S]

We are, probably trying to cover too many points at once, so I’ll start with just one point from your last post.  Hopefully we can clear that up before moving to the next.

Yes the overall entropy of the universe is increasing. However in space there isnt much there except galaxies. As the universe continues to expand and all the visible galaxies and bits of rock dissappear over your visible horizon you are effectively in an area of space with a very low entropy…….

If we are considering the entropy of the Universe a fraction of a second after the BB; we are certainly looking at the whole Universe.  It becomes important to distinguish clearly between the Universe (= observable universe) and anything else that might be hypothesised to exist.

E.g. in
 

] No it does not, the Big bang is a model of the visible universe. Space is expanding, and a microscopic volume of space now in a few trillion trillion years will occupy a larger volume of space.

You seem to be saying that I cannot make a specific proposal about the entropy of the Universe just after the BB, because some unspecified “volume of space” will expand in the distant future.   Is that right?

[pensador]

You seem to be saying that I cannot make a specific proposal about the entropy of the Universe just after the BB, because some unspecified “volume of space” will expand in the distant future.   Is that right?

There is a lot to this question. You appear to be assuming a closed area of space, which might not have been the case.
Rather than me waffle on here is a link from Ethan https://www.forbes.com/sites/startswithabang/2017/04/15/ask-ethan-what-was-the-entropy-of-the-universe-at-the-big-bang/#7b2b4ac27280

The laws of thermodynamics in the Big bang seem a bit muddled dont you think? My point being the big bang theory is only a mathematical model, which you will note does not require the high degrees of proof required in other sciences, particle physics for example. So when I look at it, I dont believe it is proven fact. It is only the current favored evolving model of the universe. Other interesting models exist, and perhaps some where in the middle of them all lies the truth.

Cosmic Cyclic Cosmology, Quantum Loop Gravity, etc etc >  the list goes on. Some of which might be partly plausible and others appear to be science fiction.

The CMBR appears to support a hot dense state of photons that spread out filling all of space. But would there be any difference to the model, if at the end of the inflationary epoch baryogenesis occurred, without the original hot dense state?
I think in my simple way of looking at things, this fits the data without all matter in the universe coming out of an area the size of a grapefruit.

It is possible if Hawking radiation is correct, that the inflation of space might have caused particle production, from the zero point energy of the vacuum.  Here is a wiki on the subject https://en.wikipedia.org/wiki/Zero-point_energy

Edit just remembered this link posted some time ago https://profmattstrassler.com/2014/03/17/my-new-articles-on-big-bang-inflation-etc/ enjoy

[pensador]

Edit to answer the OP was the big bang the beginning of the universe? Likely it was not the beginning of the entire universe, maybe just the visible universe.

Ref various different views on inflationary models http://universe-review.ca/R02-13-inflation.htm this is a quick overview.

I like the idea of repeated big bangs, in an already existing universe. It appears to step around the need for inflation and a beginning of time. Our visible universe might be circa 40 billion years old, but an older universe likely exists beyond what can be observed.

[Bill S]

Flummoxed, I'm unlikely to have time to follow the links in #37 for a while.  I've found both Siegel and Strassler very helpful in the past.  In the meantime:

I like the idea of repeated big bangs, in an already existing universe. It appears to step around the need for inflation and a beginning of time. Our visible universe might be circa 40 billion years old, but an older universe likely exists beyond what can be observed.

Starting everything at the BB, or any specific point, involves the something-from-nothing problem.
Multiple, bouncing or otherwise repeating universes, run into "Turtles-all-the-way-down" problem.
What about an infinite, eternal, changeless cosmos, of which our Universe is a 3+1D "shadow". No creation from nothing, no infinite regression!   

Just a thought.