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Simple question about the universe

Discussion in 'Science' started by Anteros, Sep 22, 2012.

  1. Anteros

    Anteros Member

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    So, in the rather distant future when the universe has degraded to the point where electrons, protrons and neutrons don't exist and gravity becomes the dominant/only force, what happens. Do we have any chance of slowing/reversing our expansion and crunching?

    Been thinking about a lot today and can't find any information on theroies regarding it. I have a bbq on thursday and need to know if i should be prepared.
     
  2. SLATYE

    SLATYE SLATYE, not SLAYTE

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    As far as we can tell now, no. The laws of thermodynamics state that the entropy in the universe as a whole will always increase, until it reaches the point where energy is perfectly evenly distributed. At this point all these complex things (like people, planets, stars, etc) cannot exist, so that's the end of it for us.

    Up until very close to the end, we can continue to create local reductions in entropy (to allow life) at the expense of more quickly increasing the universe's entropy. It's a bit like a battery going flat - you can continue to extract the same amount of power by increasing the current to compensate for a lower voltage, but increasing the current just makes it go flat faster.
     
  3. power

    power Member

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    I think your Thursday bbq should be just fine.
     
  4. Zylatis

    Zylatis Member

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  5. OP
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    Anteros

    Anteros Member

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    So the laws of physics should stay the same even when the basis all physical matter has broken down?
     
  6. spludgey

    spludgey Member

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    Hang on, electrons, protons and neutrons are going to break down?
    Why?
     
  7. OP
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    Anteros

    Anteros Member

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    Okay, mis-understood what i was reading, only protrons decay. Still, i would think that would have to have some effect on the current laws of physics.
     
  8. elementalelf

    elementalelf Member

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    FWIW, there are some theories regarding the speed of light slowing down, if that is true, your thursday BBQ is all good, just try to figure it out before then and let us know :tongue:
     
  9. Sakinho

    Sakinho Member

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    Neutrons decay too! Outside an atomic nucleus they're actually relatively unstable, with a half-life of around 10 minutes. Inside a nucleus they're expected to decay with about the same half-life as the proton. As protons in an atom decay, the atom becomes too neutron-rich and beta decay is then favourable, turning neutrons into protons, which will then themselves decay. There is also no bound state made purely of multiple neutrons. Therefore, all neutrons in the Universe will decay into protons, and all protons will decay into photons and positrons. The end state of the Universe (assuming it is flat) will be a tremendously sparse collection of neutrinos, photons, maybe some electrons/positrons (electrons and positrons are stable but should annihilate mutually, however I think the expansion of the Universe will dilute them so much that it'll take an immense amount of time for the pairs to find each other and decay) and possibly dark matter remnants.

    As far as I understand, proton decay is practically guaranteed, the only problem is determining the timescale. GUTs usually allow a (relatively) easy decay process and stipulate a half-life on the order of 1040 yr or so, but even if it turns out that proton decay is a strongly forbidden process, there are many other ways for it to happen, all of which can't be blocked as far as I know. Even virtual black holes might play a role. The more forbidden the decay is, the longer the half-life though. It might take as much as 10200 yr but it should happen.

    For anyone in this thread, here is a very good article about the end of the Universe. I've read it a few times over, and it still blows me away every time. The physics of deep time is truly fascinating.
     
  10. elementalelf

    elementalelf Member

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    Easy solution is to take entropy to its limit.

    Entropy is merely the decay of a pattern.

    If the universe isn't ordered, there will be a point where the "pattern" ceases.

    Since the only relative point we can use is time;
    as time approaches infinity, order approaches 0.



    No need to worry, sunday BBQ probably alright too.
     
  11. OP
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    Anteros

    Anteros Member

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    BBQ went off without a hitch, in casr anyone was wondering.

    Thanks for the link Sakinho, reading through it slowly in my spare time, loomed really interesting. Now to annoy others around me with things I know that they have never thought of :)
     
  12. Hyram

    Hyram Member

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    Definitely not the first time that question has been asked ...

    ... but it is definitely "The Last Question".

     
  13. Gunna

    Gunna Member

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    Wouldn't this model potentially mean that could never happen?
     

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