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Energy of the universe

  1. Jun 10, 2009 #1
    So I hope this counts as a valid physics question, I didn't think it fit in philosophy even though it's probably speculative.

    My question is about where the universe gets its energy.
    From what science knows about the universe, would it need a giant power source to function, or is it a self contained system where the energy is somehow recycling or self sustained via some method unknown to me?

    I mean where does energy come from? Is it a side effect of the big bang that will run out?

    Any insight appreciated.
  2. jcsd
  3. Jun 10, 2009 #2
    Hi there,

    From what is known, our Universe was created from energy. The energy contained in our Universe has not changed (counting the mass as energy) since its creation. Therefore, finding the origins of energy would be the same as finding the origins of the big bang.

  4. Jun 10, 2009 #3


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    Gold Member

    All the energy in the universe is what's in it now.

    The "power sources" are things such as
    - the heat of stars
    - the potential energy of galaxies falling toward each other.

    Energy doesn't "run out" the way it does in batteries, what happens is :
    - the stars cool while heating up the surrounding matter. Eventually, the two temps are the same and no more energy can be extracted.
    - the galaxies fall together, shedding their potential energy (which goes in to star formation, then you're back at stars cooling)

    Ultimately, the energy "runs out" when the universe is one giant homogenous sea of warm atoms and there's no flow of energy from one place to another.
  5. Jun 10, 2009 #4
    Conservation of energy is one of the fundamental laws/tenants of physics. Energy can never be created nor destroyed, merely change forms
  6. Jun 15, 2009 #5
    Taken into account mass as a form of energy.
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