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Does mass exist when matter is completely inert?

  1. Jun 19, 2013 #1
    I've been thinking about mass and the question occurred to me: If a particle is completely inert i.e. absolutely no motion whatsoever then does it still have a mass? I ask because, as far as I understand it, everything we've ever measured cannot strictly be said to be inert. That is: Every particle we've measured is always under some kind of motion.

    Thanks, :)
     
  2. jcsd
  3. Jun 19, 2013 #2

    Dale

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    If you are talking about the physics of a situation that is, in your mind, impossible even in principle, then is it really physics? In other words, if you consider every particle ever measured to be in motion then it seems that you believe that being at rest is impossible, so how can you answer questions about impossible states?

    In all possible states tested so far massive particles do not lose their mass due to moving slowly.
     
  4. Jun 19, 2013 #3
    You can wait until God knows when all heat (particle motion) energy is over in the universe and you will still have the gravitational potential energy that is a property of something that has MASS.
    Every time your car stops , it doesn't disappear in thin air does it?
    Well , why do you think black holes form? Well yes even after supernova the particles making up stars are still in some motion but even if they would suddenly loose all their motion a black hole would still form.
     
  5. Jun 19, 2013 #4
    What happens (theoretically) to a system of identical fermions (which cannot occupy the same quantum state) at absolute zero? The system still has non-zero Fermi energy. Doesn't this imply fermions still have mass at 0 K (no translational motion)?
     
    Last edited: Jun 19, 2013
  6. Jun 19, 2013 #5
    I was thinking specifically in terms of Roger Penrose's conformal cyclic cosmology. In his hypothesis mass is required to eventually decay over time. I wondered whether it is plausible that instead of mass decaying, all motion stops at the heat death and then there is no more mass.
     
  7. Jun 19, 2013 #6

    ZapperZ

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    How does heat death equate to no mass? No thermal energy is not the same as no mass.

    Zz.
     
  8. Jun 19, 2013 #7

    Dale

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    Penrose's CCC is a solution in GR, and in GR the stress-energy tensor follows a well-known continuity equation which ensures that mass/energy etc. cannot simply disappear.
     
  9. Jun 19, 2013 #8
    Do particles still have gravitational potential energy if they are trapped in their own light cones; isolated from everything else (eg. when space has sufficiently expanded)? Surely GPE only exists when a particle is in relation to other particles...?
     
  10. Jun 19, 2013 #9
    gravity is a property of mass , any kind and any size. particles including.Just like the need to sleep is a property of humans any color, size or shape.

    Now as long as physics knows , there is no know way to stop gravity or shield it.You can shield Em radiation and photons etc but you cannot shield gravity.
    No matter how many particles would there be left in space even if one it still would have a gravitational potential to it.
    The strength of gravity falls of with distance and obeys the inverse square law.

    http://en.wikipedia.org/wiki/Inverse-square_law

    And no a lightcone cannot stop gravity , indeed light itself is influenced by it.Photons to be exact curve around strong gravitational fields and when the fields get extremely strong photons "fall into them" Hence Black holes.
     
  11. Jun 19, 2013 #10

    mfb

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    "absolutely no motion whatsoever" in which reference frame?
    For every particle, at every moment in time, there are reference frames where it is at rest, and others where it is not. Do objects have mass? Sure. Mass is invariant under coordinate transformations, so it is the same in all reference frames.
     
  12. Jun 20, 2013 #11

    ZapperZ

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    I'm still waiting for you to show what physics that we know of today actually support any of what you have posted here. You seem to throw out a lot of claims, but you didn't actually support those with any established physics.

    So, can you at least cite a paper that equate heat death with no mass? Can we at least settle things one at a time before bringing up something else?

    Zz.
     
  13. Jun 20, 2013 #12

    Dale

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    Thread closed pending moderation.
     
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