What Determines the Precise Chronology of the Universe?

[DiracPool]

I was just reading this wiki page:

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

and was wondering where can I find the seminal papers or books that derived these amazingly exact figures of all these nucleation and decoupling, etc. events at such specific instances (e.g., 10^-43s, 10^-8s, 1 second, 10 seconds, etc.) And then after that, we have "approximately 70k years, approximately 377k years, etc., for later events. Why so specific in the beginning, and not so much later?

What is the mathematical model that drives this cosmological model and how can it be so precise? Is it general relativity per se or some derivative theory thereof? Quantum field theory?

 

[Simon Bridge]

Do not confuse small numbers for accuracy - the initial figures are approximate too.
For instance, from your source, the Grand unification epoch is between 10[sup–43[/sup seconds and 10^–36 seconds after the Big Bang.
That is a variation, Δt/t, of 99.99999% ...

However, we do know about fundamental process to a high degree of accuracy (because we can study them up close) - and that is what the early numbers are based on. Later stages depend on effects over long distances, so the uncertainty on the distances involved will contribute to the variation. Not as good at measuring long distances as we are at measuring small times.

The later stages are modeled in general relativity. On the small scale, QFT dominates.

The article follows a standard theory ... it is just a model and makes a bunch of assumptions.
The way to read it is "if the big bang hypothesis is true, then something close to the following has to happen in order to end up with a universe much like what we see around us."

The wikipedia article has references, and those references also have references.
Hunting down all the papers would be quite a mission. Have fun.

 

[Naty1]

For instance, from your source, the Grand unification epoch is between 10[sup–43[/sup seconds and 10–36 seconds after the Big Bang.
That is a variation, Δt/t, of 99.99999% ...

I've always understood that to be an interval, not a span of possibles points...in other words
grand unification took some time.

Yes...I confirmed, it's explained under 'Grand Unification Epoch' in Wikipedia...a separate article.

I don't know how accurate those points in time are, but I have seen them in multiple sources. My guess is they are 'exact' based on a simplified model and/or assumptions, so one gets a particular 'exact' number from an agreed upon [approximate] model.

 

[Simon Bridge]

Ah - OK. But the main point remains.

Looking more carefully - the numbers are order-of-magnitude estimates.
Still not "accurate".

10^-43s is the Plank time ... so that's the earliest anything could have been separate.
GR has a singularity at t=0, giving size=0 ... but (oversimplifying) QM means that nothing gets smaller than 10^-33cm ... below that concepts of "time" and "distance" are ambiguous. What this means is that the earliest time we can stick into our math and get sensible results is the Plank time. That means we can be pretty definite about it.

The others will be similar.
I notice all the references are textbooks ... hopefully the texts have references.
I wonder if there's a list of fundamental sources for this someplace...

wikipedia has a history mentioning important papers to hunt for:
http://en.wikipedia.org/wiki/Cosmology

 

[Mordred]

It would help if you refer to the earlier periods as epochs which is a key word in googling for references. Even then finding good material not in textbooks is tricky.

here is a couple of links

http://www.physicsoftheuniverse.com/topics_bigbang_timeline.html

http://www.nicadd.niu.edu/~bterzic/PHYS652/Lecture_13.pdf

the second one is better than the first in my opinion.

http://physics.uoregon.edu/~jimbrau/astr123/notes/chapter27.html

this link is related if you look closely however unlike the other chronologies this one describes one possibility when dark matter would form.

http://www.fas.org/sgp/othergov/doe/lanl/pubs/00285549.pdf

As I stated finding good information on the BB epochs is tricky usually they are relatively the same as the articles I posted.
Another search that sometimes gets results though its described later on is BB nucleosynthesis. Even though this occurs after the Epochs it has some origins during the epochs.

Hope this helps

 

[Mordred]

So what does the above mean in current cosmology,unfortunately to answer that you have to describe a couple of specific models which you may or may not agree with.

The Epochs are essentially a break down of matter and the forces, its loosely based on symmetry. Prior to
10^-43 seconds it does not cover. the other model this describes in a sense is a universe from nothing model. Lawrence R Krauss supports this idea. Other models related is the original false vacuum model described by A.Guth.
Essentially according to the combination of the two during the Planck epoch there is no matter, or forces. However there is quantum fluctuations. (see false Vacuum) Heisenburg uncertainty principle.
The forces develop during the late epochs so does quarks leptions etc. see the epoch list for history of formation.

Fundamentaly the epochs list is an atempt of Grand unification theory where everything combined, balances to a net energy, matter and force balance of zero.
I doubt you find recent literature on this subject however as it does not address dark matter or dark energy.

As such I have never seen the epochs referenced in current cosmology of the hot big bang model or Lambda CDM model which is the current concordance model. LambdaCDM for the OP is essntially hot big bang with dark matter dark energy added to it, in the FLRW metrics the CDM describes cold (non relativistic) dark matter.

 

[DiracPool]

Thanks for the leads everyone. So am I getting that the standard BB chronology model that we get these time epoch figures from comes from a combination of GR and QM? If so, is it a hybrid model of both, somehow artifically forced to overcome the incompatibilities of the two models? Or perhaps they are just artifically "Frankensteined" together to force a timeline? I guess I'm just trying to see how the incompatibility issue was addressed in order to develop the model. The wiki article I referenced mentions the Lambda-CMD model. Could this be the hybrid I'm thinking of? The mathematical details of these models are a bit advanced for me to make a quick assessment of this. In a related sense, what about QFT, loop quantum gravity, string theories, etc. Do each of these models mathematically find the same times for the epochs discussed in that wiki page?

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

Or do each have varying stories?

Edit: I apologize for any inconsistencies in the temporal flow of this post as I wrote and sent it before Modreds previous post

 

[Mordred]

QUOTE=DiracPool;4358789]Thanks for the leads everyone. So am I getting that the standard BB chronology model that we get these time epoch figures from comes from a combination of GR and QM? If so, is it a hybrid model of both, somehow artifically forced to overcome the incompatibilities of the two models? Or perhaps they are just artifically "Frankensteined" together to force a timeline? I guess I'm just trying to see how the incompatibility issue was addressed in order to develop the model. The wiki article I referenced mentions the Lambda-CMD model. Could this be the hybrid I'm thinking of? The mathematical details of these models are a bit advanced for me to make a quick assessment of this. In a related sense, what about QFT, loop quantum gravity, string theories, etc. Do each of these models mathematically find the same times for the epochs discussed in that wiki page?

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

Or do each have varying stories?[/QUOTE]

Wish I could answer this more accurately with a timeline of developments lol. I've been researching the timeline of developments of the hot BB model however seperating data into a correct sequence is daunting. The closest match I've found on the Epochs is its an attempt of BB model to incorperate symmetry and QM by extension. The BB model already had GR as its basis.

One of the earliest forms of the big bang model is the false vacuum model, this developed into the inflationary model, chaotic inflationary model, some symmetry models some string theory models. the list goes on.

Essentially any cosmology model that describes the history of the universe is a collection of related models. The Hot big bang model incorperates lots of related models, same with LCDM or $\Lambda$CDM. LQC also is a collection of models from a variety of other related physics.
Thats one of the reasons I feel to truly understand a model or theory one must understand its history of development.

$\Lambda$CDM is the often cited as the best fit to observation however their are competitive models such as LQC. Hence its considered the current concordance model. Prior to that the concordance model was BB without dark matter or energy. Concordance model is simply put considered the most agreed upon model at a given time of history.

 

[marcus]

...

$\Lambda$CDM is the often cited as the best fit to observation however their are competitive models such as LQC..

I don't know of anyone who says LCDM is a better fit to the observational data than LQC, since LQC reproduces the goodness of with with the data. You probably heard someone say LCDM is "best fit" from among classical-type models, and thought they were making a broader comparison.

LQC should always be included in your concept of "best fit".

(Until such time as somebody derives a DIFFERENT testable PREDICTION and that prediction is tested by some more refined observation. Then we will be able to say A is better fit than B or B is better fit than A.)

 

[Mordred]

Fair enough I'm not familiar enough with LQC to know how far its come. So I will take your word for it.

 

[phinds]

DiracPool, Weinberg did some early work on the chronology --- you might check out his "The First Three Minutes". I think you can still get a paperback copy pretty cheaply on Amazon.

 

[DiracPool]

DiracPool, Weinberg did some early work on the chronology --- you might check out his "The First Three Minutes". I think you can still get a paperback copy pretty cheaply on Amazon.

Great, thanks for the reference.

 

[yenchin]

Thanks for the leads everyone. So am I getting that the standard BB chronology model that we get these time epoch figures from comes from a combination of GR and QM? If so, is it a hybrid model of both, somehow artifically forced to overcome the incompatibilities of the two models? Or perhaps they are just artifically "Frankensteined" together to force a timeline?

The incompatibility between QM and GR only becomes important at certain regimes, such as at the "singularities" of black holes and Big Bang. This is not saying that we cannot apply both quantum field theoretic method with GR -- we certainly know how to do it at the right regime, e.g. semi-classical type of calculation. Hawking emission of black hole is one such type of calculation.

 

[Devils]

I was just reading this wiki page:

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

http://upload.wikimedia.org/wikiped...no_WMAP.jpg/440px-CMB_Timeline300_no_WMAP.jpg

Shouldn't this be a cone rather than cylinder/bell.

 

[Simon Bridge]

... only if the expansion were constant.

Be careful with that pic though - it is for illustration only.
Only one dimension of space is shown - the volume "inside" the bell has no meaning but the artist has filled it with stuff as if it does.

 

[Naty1]

Mordred...Now I am angry with you! on two counts!

http://www.nicadd.niu.edu/~bterzic/P...Lecture_13.pdf

the second one is better than the first in my opinion.

That does look like a nice series of26 lectures ...
[1]it looks so good I am going to have to read it...


[2]My 92 year old neighbor is out doing his spring lawn work, outclassing my efforts in my yard, and my wife says I am spending too much time on the computer already...]

I will tell her 'See Mordred' next time she let's loose on me!

 

[Mordred]

Lol its funny that my wife has the same complaints. As she claims "I don't know why your so addicted to this space stuff you'll never go there".

Lol

 

[Chalnoth]

I don't know of anyone who says LCDM is a better fit to the observational data than LQC,

I'm not sure this statement even makes sense, as LCDM makes no statement about inflation, and LQC makes no statement about the late-time makeup of our universe (as far as I know). The two apply to cosmology in different regimes, so that I don't think it makes sense to compare them in this way.

 

[DiracPool]

... only if the expansion were constant.

Be careful with that pic though - it is for illustration only.
Only one dimension of space is shown - the volume "inside" the bell has no meaning but the artist has filled it with stuff as if it does.

http://upload.wikimedia.org/wikiped...no_WMAP.jpg/440px-CMB_Timeline300_no_WMAP.jpg

Am I correst in guessing that the flaring out of the bell at the end reflects the transition from dark matter dominance to dark energy dominance roughly 7BYA?

 

[Chalnoth]

http://upload.wikimedia.org/wikiped...no_WMAP.jpg/440px-CMB_Timeline300_no_WMAP.jpg

Am I correst in guessing that the flaring out of the bell at the end reflects the transition from dark matter dominance to dark energy dominance roughly 7BYA?

Yes.

 

[rbj]

just testing

 

[Mordred]

Chronos posted a review paper on LCDM recently. Its got a decent coverage of chronology without the maths. It also does a decent job of describing the BB paradigm.


http://arxiv.org/abs/1304.4446

 

[DiracPool]

Chronos posted a review paper on LCDM recently. Its got a decent coverage of chronology without the maths. It also does a decent job of describing the BB paradigm.


http://arxiv.org/abs/1304.4446

Looks like a good article, thanks for the reference!

 

[Mordred]

Found this article.

http://web.njit.edu/~gary/202/Lecture26.html

The explanation of how the epochs are defined is better done. The main factors I can see is the overall energy or temperature. The accuracy of symmetry. Assuming symmetry is correct (the GUT portion still needs work) at higher energy levels the forces become indistinquishable from each other (GUT). The other particles cannot form until the energy levels lower to cause decoupling.I was always wondering how they derived the epochs lol.

Edit: its more complicated than that simple explanation. Somehow I don't feel that anyone wants to pour through a 298 page article for more thorough details. Lol I'm a sucker for punishment