Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Chronology of the universe

  1. Apr 23, 2013 #1
    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?
     
  2. jcsd
  3. Apr 23, 2013 #2

    Simon Bridge

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    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.
     
    Last edited: Apr 23, 2013
  4. Apr 23, 2013 #3
     
    Last edited: Apr 23, 2013
  5. Apr 23, 2013 #4

    Simon Bridge

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    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 text books ... 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
     
  6. Apr 23, 2013 #5
    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 text books 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 [Broken]

    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
     
    Last edited by a moderator: May 6, 2017
  7. Apr 23, 2013 #6
    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.
     
    Last edited: Apr 23, 2013
  8. Apr 23, 2013 #7
    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
     
    Last edited: Apr 23, 2013
  9. Apr 23, 2013 #8
    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 [itex]\Lambda[/itex]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.

    [itex]\Lambda[/itex]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.
     
  10. Apr 23, 2013 #9

    marcus

    User Avatar
    Science Advisor
    Gold Member
    Dearly Missed

    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.)
     
  11. Apr 23, 2013 #10
    Fair enough I'm not familiar enough with LQC to know how far its come. So I will take your word for it.
     
  12. Apr 23, 2013 #11

    phinds

    User Avatar
    Gold Member
    2016 Award

    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.
     
  13. Apr 24, 2013 #12
    Great, thanks for the reference.
     
  14. Apr 24, 2013 #13
    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.
     
  15. Apr 24, 2013 #14
  16. Apr 24, 2013 #15

    Simon Bridge

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    ... 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.
     
  17. Apr 24, 2013 #16
    Mordred...Now I am angry with you!!! on two counts!!


    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 lets loose on me!!!
     
    Last edited by a moderator: May 6, 2017
  18. Apr 24, 2013 #17
    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
     
  19. Apr 24, 2013 #18

    Chalnoth

    User Avatar
    Science Advisor

    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.
     
  20. Apr 24, 2013 #19
    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?
     
  21. Apr 24, 2013 #20

    Chalnoth

    User Avatar
    Science Advisor

Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Chronology of the universe
  1. The universe (Replies: 3)

  2. The universe (Replies: 4)

Loading...