What caused the big bang?

[Genecks]

I spent some time over a month ago seeing what model for the big bang exists. As far as I was able to get, the argument was that a quantum fluctuation generated the universe. Is that quantum fluctuation argument the current view on how the universe was generated?

[ajb]

Is that quantum fluctuation argument the current view on how the universe was generated?

Simply put no-one has a proper understanding of this and so there is not really a "current view". It is all very speculative and outside of well tested physics.

[Genecks]

Well, since I'm going to re-use this thread, I'll pose another question: Why didn't the big bang fizzle out right away?

 

If I've read correctly, the theory is that we live in a zero-energy universe, whereby everything cancels out. I can only assume it had something to do with geometry, perhaps the universe beginning at the inner-side surface of a sphere and blowing inward toward the center; but that seems contradicting, as things are allegedly accelerating away from each other.

Edited May 4, 2014 by Genecks

[ajb]

If I've read correctly, the theory is that we live in a zero-energy universe, whereby everything cancels out.

Why zero energy?

 

The FWR metrics which under some very general assumptions (independent of GR) describe the geometry of our Universe. These solutions are time dependent and so energy will not be conserved.

[Orodruin]

Well, since I'm going to re-use this thread, I'll pose another question: Why didn't the big bang fizzle out right away?

 

If I've read correctly, the theory is that we live in a zero-energy universe, whereby everything cancels out. I can only assume it had something to do with geometry, perhaps the universe beginning at the inner-side surface of a sphere and blowing inward toward the center; but that seems contradicting, as things are allegedly accelerating away from each other.

 

Well simply put the Universe did not contain enough matter and radiation for it to contract immediately. Instead the recent BICEP2 results seem to be pointing to the early Universe undergoing an inflationary phase, in some sense similar to the one we currently seem to be about to enter.

 

It should be said that, although we have a pretty good picture of the formation of the Universe after very early times, at some point we would typically run into problems of our currently established theories not being applicable. It should also be said that there are also some things we do not yet understand about the standard cosmology as well, such as how the dark matter was created and why there is an overabundance of matter over antimatter.

[Mordred]

Well, since I'm going to re-use this thread, I'll pose another question: Why didn't the big bang fizzle out right away?

good question. The hot dense state of the big bang model prior to inflation was in thermal equilibrium, I'll simply start with the quark-gluon plasma state. Prior to being able to collapse, inflation occured. This effectively and suddenly increased the volume of the universe by roughly 60 e-folds. Exact value depends on the model of inflation. This caused a sudden cooling due to a sudden increase in volume. However towards the end of inflation there is also a significant reheating phase. This places the universe back into thermal equilibrium however over a larger volume. No one knows the mechanism of the comological constant, however it continues to expand the universe. Now the cosmological constant keeps the universe expanding rather than gravity causing a collapse

[Genecks]

good question. The hot dense state of the big bang model prior to inflation was in thermal equilibrium, I'll simply start with the quark-gluon plasma state. Prior to being able to collapse, inflation occured. This effectively and suddenly increased the volume of the universe by roughly 60 e-folds. Exact value depends on the model of inflation. This caused a sudden cooling due to a sudden increase in volume. However towards the end of inflation there is also a significant reheating phase. This places the universe back into thermal equilibrium however over a larger volume. No one knows the mechanism of the comological constant, however it continues to expand the universe. Now the cosmological constant keeps the universe expanding rather than gravity causing a collapse

 

If I understand your argument correctly, the beginning geometry was a point in space or spacetime. From there, inflation occurred, which prevented a collapse (fizzle) from occurring. Is that right?

[Mordred]

Correct, the hot big bang model only explains the history of our observable universe or rather shared causality/lightcone. We do not know if the universe is finite or infinite. We can only measure our observable portion and assume that the regions outside our observable portion follows the same understanding. This is unfortunately often misrepresented by multi-media programs and article. They often show the universe as starting from some infinitely small and superdense point. This is not predicted by the hot big bang model. Now speaking of observational limits, we cannot make any observations prior to the dark ages

http://en.wikipedia.org/wiki/Timeline_of_the_Big_Bang#Dark_Ages

so how did we determine the chronology of the epochs represented by this list?

http://en.wikipedia.org/wiki/Chronology_of_the_universe

 

The answer to that is based on studies at nuclear reactors and the LHC. In other words our understanding of particle physics. However be warned the list represented by that wiki page is based on an older symmetry breaking understanding, SU(5). I haven't seen any correlation for say SU(32). Most current textbooks and early universe particle physics textbooks no longer include the epochs.

 

Putting that aside the BB model starts at 10^-43 seconds, prior to that our understanding of physics cannot describe the conditions at this point in time. However due to our understanding of thermodynamics, the universe must have been expanding prior to inflation. No one knows for sure the rate of expansion at this time but you can calculate the rate of expansion via the radiation equation of state corresponding the temperature and energy-density. as shown on page 41, equation 4.0.1 of this article.

 

http://www.wiese.itp.unibe.ch/lectures/universe.pdf:" Particle Physics of the Early universe" by Uwe-Jens Wiese Thermodynamics, Big bang Nucleosynthesis

 

however you must keep in mind we have no means of knowing the exact temperature, we cannot observe this period, so we apply our understanding of particle physics,ideal gas laws and cosmology to calculate an approximation.

inflation is said to occur at roughly 10^-36 sec however this depends on which inflation model is correct (there is over 60 still viable observational fit models). However the recent Planck favors the single scalar models with slow roll. This however does not discount the multi scalar models. A full list of viable models is here

Encyclopaedia Inflationaris

http://arxiv.org/abs/1303.3787

 

hope this helps the second link of my signature has a site which is a compiled list of articles I have found useful to teach cosmology over the years. None of the material there is conjectural and is all based on textbook concordance model of the LCDM. However I did include some loop quantum cosmology articles, as it has the same predictable ability as LCDM. (LCDM's closest competitor)

Edited May 11, 2014 by Mordred

[MirceaKitsune]

This is one of the things science will have a very hard time knowing with 100% certainty, and where the best bet seems like going with what makes most sense and fits most logics and observations.

 

Myself, I'm a believer of the theory that black holes form new universes, and an universe ceases existing when all and any matter in it is absorbed by black holes. In other words, the big bang in one universe might be the moment when a collapsed star can no longer take it and becomes a black hole inside another universe. Each universe might then be the interior of a black hole. If this system is indeed correct, I personally believe it recurses infinitely, and each universe leads to other universes which do the same in turn.

[Mordred]

This model fits observations the least. Here is several reasons as to why. Universe according to observations in homogeneous and isotropic. No preferred location and direction. (essentially uniform in distribution)

Now lets look at the properties of black holes. They can spin or be static. They can only grow in size with the material near them or within their gravitational influence.

As such their feeding rates are inconsistent.

 

Now lets use Poplowskii's spin and torsion model

 

http://news.nationalgeographic.com/news/2014/02/140218-black-hole-blast-explains-big-bang/

 

"The compacting process halts, according to Dr. Poplawski, because black holes spin. They spin extremely rapidly, possibly close to the speed of light. And this spin endows the compacted seed with a huge amount of torsion. It's not just small and heavy; it's also twisted and compressed, like one of those jokey spring-loaded snakes in a can. Which can suddenly unspring, with a bang. Make that a Big Bang—or what Dr. Poplawski prefers to call "the big bounce.""

 

http://arxiv.org/abs/1105.6127

rather than post all his articles and the various metrics he's tried to make his model work you can look through them.

http://arxiv.org/a/poplawski_n_1

 

He has several key problems that he struggles to address. Acoording to his model the the universe has a spin and torsion.

 

problem 1) a rotating universe cannot be isotropic and homogeneous. It will always have a preferred location and direction. Regardless of how slow it is rotating.

problem 2) a rotating black hole would impart that rotation upon our universe.

problem 3) Poplowskii's model does not have the cosmological constant, expansion is due to the rotation.

problem 4) where does inflation fit in.

problem 5) A black hole does not have consistent feeding rates. Where is the variations in energy density distributions in our universe. If a BH supply starts gobbling a star the energy it takes in increases (more material) Why do we see no evidence of this,? we should see regions of higher energy density expanding outward form the preferred location.

problem 6)Black holes gradually lose angular momentum due to Hawkings radiation in the accretion disk. For technical details see this article.

http://arxiv.org/abs/1104.5499 :''Black hole Accretion Disk'' -Handy article on accretion disk measurements provides a technical compilation of measurements involving the disk itself. also the article covers how a BH gains spin due to the laws of conservation of momentum. Coincidentally Poplowskii's models sets the torsion and spin rate as a consistent value

problem 7) The Einstein Rosen bridge his model uses and is only predicted by the EFE. has never been observed its questionable if it exists.

 

I was going to add that his model doesn't explain early large scale structure formation but I can't locate the technical paper.

Edited May 12, 2014 by Mordred

[Ten oz]

This is one of the things science will have a very hard time knowing with 100% certainty, and where the best bet seems like going with what makes most sense and fits most logics and observations.

 

Myself, I'm a believer of the theory that black holes form new universes, and an universe ceases existing when all and any matter in it is absorbed by black holes. In other words, the big bang in one universe might be the moment when a collapsed star can no longer take it and becomes a black hole inside another universe. Each universe might then be the interior of a black hole. If this system is indeed correct, I personally believe it recurses infinitely, and each universe leads to other universes which do the same in turn.

Forgive me if the following isn't organized clearly:

Black holes feed for long periods of times. If a black hole created our universes wouldn't it have fed material into our universe over a long period of time? That does not fit with current expansion models.

In order for your black hole theory to work energy during the supernova of a large enough star would have to momentarily burst into and or create another dimension and the the following expansion into that dimension immediately dissipate energy and close the connection between dimensions. The black hole which follows would never have the energy to reconnect dimensions again.

[MigL]

While I accept that inflation 'dilutes' the universe enough so that the cosmological constant becomes the driver rather than gravity, Mordred, I believe we're avoiding the issue.

 

What keeps the universe from collapsing prior to inflation ( 10^-36 sec ) ?

 

The energy density is there as expansion and inflation only affect separation or volume of space, and you can't invoke the HUP since even though we are dealing with a very short time, we have an immeasurable amount of energy which goes on to become our whole universe.

 

We are never answering the question, just pushing the goalposts back to avoid having to.

There has to be a fundamental reason and I'm not sure its a quantum gravity effect.

[Mordred]

that's the problem, we simply don't know prior to inflation, there must have been some form of expansion prior to inflation otherwise the universe would have simply collapsed. (temperatures would have also increased, instead of decreasing) However we simply do not know as we can never collect any data prior to the dark ages. There is the possibility we will one day see further than the dark ages using the cosmic neutrino background. However our ability to detect neutrinos are still too limited. So making any statements prior to inflation is purely conjectural. If we can resolve which inflationary model is correct that would also provide clues. For example if say one of the Higg's inflationary models and either supersymmetry (MSSM) or SO(10) proves to be accurate. Then we can at least develop a thermodynamic process.

 

More specifically we would be able to understand the particle physics and thermodynamic relations of the Higg's field and standard model/supersymmetric particles involved. An expanding universe is one that would cool down, that cooling allows particles to drop out of thermal equilibrium and results in phase transitions. Inflation may be a result of one of those phase transitions. One other detail is if the GUT models are accurate, then the planch epoch, GUT epoch and electroweak epoch can only occur for an expanding universe. To the best of our understanding the universe must have had a pre-inflation expansion rate. However we do not know what that rate or mechanism is due to no direct measurement data.

 

As far as quantum explanations Loop quantum cosmology has the pre inflation expansion as the result of a bounce from a previous collapsing universe. However this is only one possible model. There are numerous bounce, cyclic and universe from nothing models, as well as the black hole models

 

In the universe from nothing models, its the result of Heisenburg's uncertainty and the zero energy model. However another universe from nothing model has quantum tunneling from nothing. Similar to inflation's false vacuum to true vacuum in the false vacuum inflation model.

Edited June 1, 2014 by Mordred

[petrushka.googol]

My own primitive understanding of this is :-

 

a) Before Planck time there was no way of knowing what transpired

b) Circumstances proved propitious The set of positive (inflationary) factors outnumbered the set of negative (implosive) factors producing a net expansion.

c) It was probabilistic, much like the creation of amino acids of earth, which could be attributed to the "qualities" of the primordial "soup".

d) It was irreversible.

 

Just my way of visualizing the cosmological phenomena.