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

Hubble constant and Entropy v2

  1. Apr 13, 2015 #1
    Is there agreement here regarding the relationship between expansion of the universe from its initial conditions, entropy (2nd law), time, (and more tenuously perhaps) "evolution"?

    I asked a question awhile back that was too specific I think that tried to tie the constant of expansion to the "cause" of entropy.

    This is related to this Chaisson's (Harvard/Tufts) recent discourse on the "Rise of Complexity in Cosmic Evolution". My original question, I now realize was due to stewing on his fundamental natural association of these things - which I encountered in an earlier discourse, and was strongly influenced by. I had assumed that there was a deep and detailed physical, theoretical underpinning to his argument. Partly why Verlinde's Entropic Gravity seemed so compelling. I thought that was sort of it-ish.

    I'm rechecking, rewording my original, to just find out how fringe or mainstream Chaisson's ideas are. So "of course" or "obviously", or "yeah, if only we knew what it was", or "whatever gave you that crazy idea", or "yeah, that guy is a crackpot" is the kindof thing I'm after, since it is clearly a wide landscape.

    I can understand if some might feel this borders on the philosophy, but my estimate is that it surely must be on the appropriate side. If the answer here is, "that's not about physics", then that is also useful information.
  2. jcsd
  3. Apr 13, 2015 #2


    User Avatar
    Gold Member

    One thing is - presumably - that the CC must be low enough to allow for complex structures to arise. It pulls apart everything when ##T>1/\sqrt{\Lambda}## more or less, so any structure which hasn't had time to form by then cannot arise after that. I would expect too high a CC to even prevent nucleosynthesis, not to speak of the formation of stars, planets, and more.
  4. Apr 13, 2015 #3
    Great quote from Chaisson's book re.

    "organized systems of a physical, biological, or cultural kind everywhere apparently optimize (per unit volume or mass) the flux of energy passing through them. By "optimum" is meant an intermediate range in energy flow, below which the energy flow is too small to affect order and above which is so large as to destroy order." p.33 "Cosmic Evolution: The Rise of Complexity in Nature" Harvard University Press, London 2001.

    The notion of how it is that complexity can form, or that the wild potentiality of the physics allows it, also came up in a couple of other places (the question of how DNA, or where E.T. For instance). To me there is just this fascinating puzzle of how that gradient "action" of matter and energy occurs. I keep thinking that we have well developed models for evolutionary processes in macroscopic systems (biologics). It seems like those must somehow derive from the physics, and that perhaps they describe in somewhat novel terms the same physics at the microscopic level.
  5. Apr 13, 2015 #4


    User Avatar
    Gold Member

    I've got to read that Chaisson stuff : ) which book/articles would you recommend ?

    Otherwise, evolution is a general mechanism, I don't see what would limit it to living systems. That quote reminds me of another book about complex systems I read quite some time ago, but I can't remember which one - or perhaps it's actually the same one and I forgot the auhor :)
    Last edited: Apr 13, 2015
  6. Apr 13, 2015 #5
    Sorry man, I sound like this guys agent, or something. No agenda, I swear.
    What happened was I stumbled across this one a number of years ago only lately have I realized how profoundly affected my efforts to understand things (for better or worse.). So recently revisiting his stuff - trying to figure out if it's fit to eat...:confused:. My initial impressions are ... that I could have done worse.

    Recently started this one:
    Last edited by a moderator: May 7, 2017
  7. Apr 13, 2015 #6


    User Avatar
    Gold Member

    Thanks, some good reading ahead of me it seems : )
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook