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Energy cannot be created. Then where did it all come from?

  1. Dec 8, 2014 #1
    Someone asked me this question: If energy cannot be created then where did the Universe come from?
    Are there any websites, papers or documents concerning this question, answer?
    The first law of thermodynamics which is a version of the law of conservation of energy, adapted for thermodynamic systems. The law of conservation of energy states that the total energy of an isolated system is constant; energy can be transformed from one form to another, but cannot be created or destroyed.

    I have researched all thermodynamic processes to no avail.

    Thank You
     
  2. jcsd
  3. Dec 8, 2014 #2

    russ_watters

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    It isn't really known where the universe came from. But the statement that energy can't be created or destroyed does not apply to the universe's creation, it applies only in the universe after it was created. It wouldn't make logical sense for conservation of energy to apply to the creation of the uinverse since before the creation of the universe there was no universe for conservation of energy to be applied to!
     
  4. Dec 8, 2014 #3

    Danger

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    There is also no reason that the laws including those of thermodynamics, gravity, and whatnot came out as they did. In a different big bang, the speed of light (if light even existed) could very well be half of what it is here. If the charge of an electron was -1.3 instead of -1, you'd have a difficult time trying to find something to build a house out of. Things are the way they are just because... they are... :oldcool:
     
  5. Dec 8, 2014 #4

    Bandersnatch

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    There's also the issue of applicability of conservation of energy to cosmological scales.
    Have a look at these two articles:
    http://www.preposterousuniverse.com/blog/2010/02/22/energy-is-not-conserved/
    http://math.ucr.edu/home/baez/physics/Relativity/GR/energy_gr.html

    And perhaps this might help too:
    http://www.talkorigins.org/faqs/astronomy/bigbang.html#firstlaw
     
    Last edited: Dec 8, 2014
  6. Dec 9, 2014 #5

    ChrisVer

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    Who said anything about violation of energy?
    The total energy of the universe is conserved in BBT.
    http://machineslikeus.com/news/big-bang-beginners-13-does-big-bang-theory-violate-law-conservation-energy [Broken]
     
    Last edited by a moderator: May 7, 2017
  7. Dec 9, 2014 #6

    PeterDonis

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    As the second article Bandersnatch linked to says, it depends on how you define "energy" and how you define "conserved". These terms aren't as simple as you and the article you have linked to appear to believe.

    I strongly recommend reading both of Bandersnatch's links, but the basic error the article you linked to makes is to assume that "gravitational potential energy" is a well-defined term for the universe as a whole. It isn't; it is only well-defined in a stationary spacetime, and the universe is not stationary because it is expanding. (The first article Bandersnatch linked to goes into this in some detail.) So the analogy the article makes between analyzing the orbits of satellites around the Earth, and analyzing the universe as a whole, is not really valid.

    It turns out that, for a closed universe, you can finesse this point by coming up with a way to define "gravitational potential energy" that works similarly enough to the orbiting satellite scenario to make the analogy valid. However, note that I said "a closed universe"; the article you linked to says this too. According to our best current model, our actual universe is not closed, so this way out doesn't work.

    Btw, I should emphasize that I am in sympathy with the desire of the writer of the article you linked to, to not give religious people an excuse to say that the Big Bang theory requires something to be created out of nothing. But there is a much simpler way of doing that, which the article doesn't mention: point out that the law of conservation of energy is really a local law, not a global law: it says that energy can't be created or destroyed in any small volume of spacetime. Our current theories obey this law: in General Relativity it shows up as an identity, the Bianchi identity, which is obeyed by the Einstein Field Equation.
     
  8. Dec 9, 2014 #7
    "In any big bang model, one must deal with the problem of 'creation'. This problem has two aspects. One is that the conservation laws of physics forbid the creation of something from nothing. The other is that even if the conservation laws were inapplicable at the moment of creation, there is no apparent reason for such an event to occur."

    I suppose if every matter has an antimatter then infinite "m" created "c". Annihilation is a release of energy available to do work, proportional to the total matter and antimatter mass, in accord with the mass-energy equivalence equation, E=mc2
     
    Last edited by a moderator: May 7, 2017
  9. Dec 9, 2014 #8

    ChrisVer

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    I am sorry, I don't understand what you mean by "infinite m created c" ... it doesn't make sense.
     
  10. Dec 9, 2014 #9

    Drakkith

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    This statement is wrong. The current big bang model doesn't deal with creation. At all. It merely states that the very early universe was extremely hot and dense and expanded from there. There is no 'creation' event in the model like people think there is.
     
  11. Dec 9, 2014 #10

    bhobba

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  12. Dec 9, 2014 #11

    bhobba

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    That's not quite correct - photons for example are not conserved.

    What you are probably talking about is conservation of energy where if photons for example are created then energy must be supplied. These days that's associated with the celebrated Noether's Theorem - the application of which to the entire universe is a bit problematical as the link I gave previously detailed.

    Also, interestingly, gravitational energy in the entire universe is negative, while the energy of matter is positive and the interesting thing is they cancel to give a big fat zero - that leads to the rather interesting view of the universe from nothing.

    Thanks
    Bill
     
  13. Dec 10, 2014 #12

    timmdeeg

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    I understand that the conservation of energy is a local law. But from a pars pro toto point of view it's not clear to me why this holds for "any small volume of spacetime". Because as I understand it the ideal fluid models require that the spacetime expands at any scale, so also locally. So, something should be the reason that energy conservation in expanding spacetime is obeyed locally, though any local volume expands. Could you kindly explain?
     
  14. Dec 10, 2014 #13

    bhobba

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    Its related to the curved space-time of GR that breaks the symmetry required of Noethers theorem which is the modern basis of energy conservation -
    http://motls.blogspot.com.au/2010/08/why-and-how-energy-is-not-conserved-in.html
    'The main lesson here is that general relativity is not a theory that requires physical objects or fields to propagate in a pre-existing translationally invariant spacetime. That's why the corresponding energy conservation law justified by Noether's argument either fails, or becomes approximate, or becomes vacuous, or survives exclusively in spacetimes that preserve their "special relativistic" structure at infinity. At any rate, the status of energy conservation changes when you switch from special relativity to general relativity.'

    There are ways around the problem, but, as the link explains there is no clear consensus on what to do about it.

    It would be wrong to say that energy is not conserved in GR - its much closer to the truth to say the issue isn't clear eg its not clear energy can even be defined.

    Thanks
    Bill
     
    Last edited: Dec 10, 2014
  15. Dec 10, 2014 #14

    ChrisVer

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    However I have one question. The conservation of entropy used in cosmology comes from the conservation of energy. How is the conservation of energy used in that scheme?
    Also I'm not sure about the global thing. The vacuum energy density is constant in the universe as a whole, that means that is is always increasing with the expansion of the universe, and at a naive level it can be described by the matter/antimatter creation and annihilation happening in the vacuum which is a local thing (of course this doesn't work out fine leading to the cosmological constant problem)
     
    Last edited: Dec 10, 2014
  16. Dec 10, 2014 #15

    PeterDonis

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    Spacetime does not expand. Spacetime just is. It's a 4-dimensional geometric object. The local energy conservation law applies in each infinitesimal 4-dimensional patch of that 4-dimensional object. The fact that a particular spacetime has geometric properties that are referred to by the word "expansion" doesn't change any of that; from the 4-d point of view, "expansion" is just another word for a particular kind of geometry.
     
  17. Dec 10, 2014 #16

    PeterDonis

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    Can you give a reference? I'm not sure what you're referring to here.
     
  18. Dec 10, 2014 #17

    timmdeeg

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    Thanks, bhobba, for providing this linked article, very interesting.

    Thanks for clarifying, I was interpreting "any small volume of spacetime" erroneously.
     
  19. Dec 10, 2014 #18

    ChrisVer

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    Ah it's almost everywhere that is dealing with the BBT, see eg:
    http://www.damtp.cam.ac.uk/user/db275/Cosmology/Lectures.pdf
    At eq. 3.2.59
    and above where they use the 2nd thermodynamical law [=the conservation of energy]
     
  20. Dec 10, 2014 #19

    PeterDonis

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    The second law is the one about entropy; conservation of energy is the first law. The reference does clarify what you meant by "conservation of entropy", however; it's just the approximation (which, as the reference notes, is a good one for the universe as a whole) that the expansion of the universe is adiabatic.
     
  21. Dec 10, 2014 #20

    ChrisVer

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    I think adiabatic implies the conservation of energy?
     
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