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B Newton's law of conservation as it applies to the big bang

  1. Feb 11, 2019 #1
    I had a thought the other day and I am looking for someone to tell me why it does not work.

    In consideration of energy be neither created nor destroyed, to me this would say there is not enough energy to continue expanding the universe.

    I also make the conjecture the gravity never stop effecting any or everything else in the universe, similar to quantum entanglement.

    Any thoughts?
     
  2. jcsd
  3. Feb 11, 2019 #2

    Drakkith

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    Conservation of energy doesn't apply to the universe as a whole, since there is no way to unambiguously define the total energy of the universe under General Relativity. See here: http://math.ucr.edu/home/baez/physics/Relativity/GR/energy_gr.html

    Quantum entanglement and gravity are nothing alike, but you are correct about gravity in the sense that gravity's range is infinite.
     
  4. Feb 11, 2019 #3

    bhobba

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    Just to expand on Drakkiths excellent reply you have to understand the modern view of energy conservation. It actually follows from a very profound theorem called Noether's Theorem:
    http://math.ucr.edu/home/baez/noether.html

    The history behind it is both interesting, instructive about the climate for female students at the start of the last century, and explains why energy conservation does not apply to the universe as a whole:
    https://arstechnica.com/science/201...-the-course-of-physics-but-couldnt-get-a-job/

    To sum up because space-time is curved the symmetry required for energy conservation does not exist so even the concept of energy is up for grabs in GR as explained in the link Drakkith gave.

    Putting my mentors hat on I want to mention personal theories are not allowed on this forum. I know you just mentioned a conjecture in passing, however in the spirit of our rule against personal theories if you can resit the urge in future it will make it easier for those following the thread - they will not be distracted by side issues.

    Thanks
    Bill
     
  5. Feb 11, 2019 #4

    PeterDonis

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    Just to be clear: it's not the fact that the spacetime of the universe is curved; it's the fact that the spacetime of the universe does not have any time translation symmetry. There are curved spacetimes that do; but the curved spacetime that describes our universe is not one of them.
     
  6. Feb 11, 2019 #5
    Thank you for the replies, I only meant to say that like entanglement it would have no range.
     
  7. Feb 11, 2019 #6

    Drakkith

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    Have any links that elaborate on this but aren't quite graduate-textbook level?
     
  8. Feb 11, 2019 #7

    PeterDonis

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