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Heat death of the universe

  1. Aug 1, 2015 #1
    Dear PF Forum
    Can I ask something quoted from a closed thread?
    In a closed thread: https://www.physicsforums.com/threads/predicted-heat-death-of-the-universe.824652/
    This quote was presented by a Brian Cox. A scientist? And if he is, I'd like to ask this question.
    Is it technically possible that in the heat death of the universe, when all stars are black dwarfs, black neutron star and black holes, that there can't be a single atom left?
    The atoms aren't necessarily swept up by the black holes or celestial bodies, right.
    The black holes/black dwarf/black neutron star can still orbitiing the centre of the galactic while there are still interstellar medium? Even if their orbits are deterioting and entering SMBH event horizon, the interstellar/intergalactic medium are still there right. Or the scattered atoms just swept to the galactic core?
    In the far future, technically will all celestial body in a galaxy be joined the SMBH at the centre of the galaxy?
    If that is true, will all the SMBHs join to form just a single black hole for the universe?
    When will the time end?
    As long as the single black hole evaporates, the entropy is still increasing, right?
    If that is true, will this single black hole evaporate (by Hawking Radiation) and ceased to exist?
    And after that, what?
     
  2. jcsd
  3. Aug 1, 2015 #2

    marcus

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    IIRC Brian Cox is a particle physicist. He also writes commercial popularizations of science. Also is a media presence---used to be a rock musician.

    He is not a cosmologist and what he said there sounds kind of speculative. I wouldn't take it seriously. And it is widely thought that BH eventually evaporate.

    Roger Penrose has a different picture of the extreme future. Whether or not he's right, at least he is a cosmologist and knows more about the subject than Cox.

    I don't see why all matter would have to eventually fall into BHs.

    There are different visions of the extreme future. Just yesterday a new one came out by Kowalski-Glikman and friends. In case you are curious I'll get the link. this is really different. and who knows? it might be right : ^)
    http://arxiv.org/abs/1507.00226
    Cyclic universe from Loop Quantum Gravity
    Francesco Cianfrani, Jerzy Kowalski-Glikman, Giacomo Rosati
    (Submitted on 1 Jul 2015)
    We discuss how a cyclic model for the flat universe can be constructively derived from Loop Quantum Gravity. This model has a lower bounce, at small values of the scale factor, which shares many similarities with that of Loop Quantum Cosmology. We find that quantum gravity corrections can be also relevant at energy densities much smaller than the Planckian one and that they can induce an upper bounce at large values of the scale factor.
    4 pages
    Some other work cited in this paper
    [22] E. Alesci and F. Cianfrani, arXiv:1506.07835 [gr-qc].
    [23] J. Bilski, E. Alesci and F. Cianfrani, arXiv:1506.08579 [gr-qc].
    [24] F. Cianfrani, J. Kowalski-Glikman, G. Rosati, to appear. [
     
    Last edited: Aug 1, 2015
  4. Aug 2, 2015 #3
    Oh.
    And everything he said in that quote is speculative only?Hmmhh...:eek:
    Thanks for the link. I've visited the link, but no detail there. Perhaps there are more?
    So in simple question according to the law of thermodynamic.
    1. All stars must die?
    2. And in the far future there can only be black holes, black dwarfs and cool neutron stars? All matters are exhausted.
    3. Will the orbit of celestial bodies cease to exist also? Will the orbit deteriorate and suck in the SMBH at the galaxy centre?
    Thanks.
     
  5. Aug 2, 2015 #4

    Bandersnatch

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    John Baez has a nice, accessible, if not terribly in-depth, breakdown of the heat death future:
    http://math.ucr.edu/home/baez/end.html

    Take notice where he uses qualifying statements about the speculative nature of the whole shebang.
     
  6. Aug 2, 2015 #5

    mfb

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    Yes, they have limited fuel for fusion.

    Gas will eventually fall onto compact objects, or get ejected from the galaxy. Some free atoms, ions and electrons will be left in the vastness of the expanding universe.

    Orbits lead to the emission of gravitational waves, which means they get closer over time. For the scale of galaxies, this effect is incredibly tiny. Not sure which one is faster, evaporation of the black holes or orbital decay of everything in galaxies.
     
  7. Aug 2, 2015 #6
    From my understanding of astrophysics (as a process engineer) I would call the attention just to our contemporary observations in the UV-, VIS-, IR-spectral ranges:
    Apparently our Universe is occupied by grand and vast patterns of in- and outflows of particles and gases in the large scale environment of stars and galaxies.
    Low (e.g. HII clouds) and high velocity (e.g. jets) structures are created and are dissolved in the near and in high-z distances as well.
    Therefore convincingly and plausibly it doesn't look as if the universe would be threatened by heat death, although infinite expansion would imply this.
    Actually and quite the contrary it seems that stabilizing recovery processes are happenening, mainly related to the re-formation of neutrons, positrons and hydrogen.
    I would hazard this guess just from what is witnessed by the latest views through our telescopes, spectrometers and detectors.
     
  8. Aug 2, 2015 #7

    mfb

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    It doesn't matter. The amount of hydrogen is finite. No matter where it is, it can release energy by fusion at most once. The same applies to helium (although it can be created by fusing hydrogen - that process is finite as well) and all other elements.
    Unless some completely new physics is discovered, ongoing expansion means the heat death is inevitable.
    Please give a (peer-reviewed) reference for that statement.
     
  9. Aug 2, 2015 #8
    Wow, I didn't read that post before mfb reply. Quite interesting.
    If this is true, why just neutrons, positrons and hydrogen?
    Matter hydrogen or anti matter hydrogen? You mean proton? or Anti proton?
    But it doesn't make sense if positron and proton, then the universe charge will be imbalance. Or it can be imbalance? I read that in [EDIT hadrongenesis] baryongenesis and lepto genesis the number of proton and electron are somewhat equal. No remains of antimatter.
     
    Last edited: Aug 2, 2015
  10. Aug 2, 2015 #9
    I just remember, another Brian, Brian May is a guitarist from Queen and a Phd in astrophysics.
     
  11. Aug 2, 2015 #10
    Thank you for your reply:
    Sorry, it is not yet a statement but, as I wrote, a strong guess or a plausible assumption or thesis:
    (already suggested 20...30 years ago, not by me)
    There are weak (van der vaals) and strong (nuclear) processes for the recovery of elementary hydrogen
    - weak: in the environment of stars the reduction to H2 on dust particles from hydrocarbons
    e.g. arXiv:astro-ph/0205503 , C.Gry et al.: H2 formation and excitation in the diffuse interstellar medium
    (see many publications under search item "H2 Formation")
    - strong (and as well challanging): in the vicinity of neutron stars and pulsars ,
    e.g. arXiv:1402.5088, R. Kothes et al.: G141.2+5.0, a new Pulsar Wind Nebula discovered in the Cygnus Arm of the Milky Way
    ( see many publications under search item "pulsar wind")
    I think this could be a great research topic in the next decades...,
    mainly the[/PLAIN] [Broken] re-estimation and calculation of the H-balance within a galaxy or a cluster
     
    Last edited by a moderator: May 7, 2017
  12. Aug 2, 2015 #11

    Bandersnatch

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    @grauitate neither of the two processes leads to fission of helium or other pre-iron nuclei in order to recover hydrogen.
    Once hydrogen is fused into helium in a star, it cannot be recovered without net energy loss, hence the total amount of energy available in the universe is limited.
     
  13. Aug 2, 2015 #12
     
  14. Aug 2, 2015 #13

    mfb

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    I'm not talking about chemical reactions, the number of hydrogen nuclei (= the number of protons not part of larger nuclei) is going down, and there is no mechanism that produces them in relevant quantities.
     
  15. Aug 2, 2015 #14
    Sorry, I made a mistake: Instead of a reply I quoted again. Please seee my quote.
     
  16. Aug 2, 2015 #15
    That's what I thought until I checked Wikipedia. I sure don't know which of differing views is more or less speculative, but this article seems less sure of the final outcome.
    https://en.wikipedia.org/wiki/Heat_death_of_the_universe
    See current status for an overview.

    I checked Roger Penrose THE ROAD TO REALITY thinking maybe with his interest in black holes he'd have a view on the final outcome. I could not find such a specific view. He is a firm believer in the second law of thermodynamics, entropy increases, and supports mfb's general description.

    Penrose claims heat death, entropy increase, is not dependent on the expansion of the universe. Nor does he subscribe to the idea that there is any meaningful distinction between an 'isolated' and an 'expanding' universe. So whatever the details, in you believe entropy increases, that means information is dissipated and eventually an equilibrium is reached where 'nothing' can take place. There is no energy left for energy consuming processes.
    I wonder if there is any room left for any type of vacuum energy.
     
  17. Aug 2, 2015 #16

    mfb

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    All the models with exponential expansion (in the long run) predict a "boring" end. Call it heat death, or find a different name - does not matter.
     
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