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I Question about Relatavistic mass

  1. Oct 24, 2016 #1

    DHF

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    I am trying to get my head abound something and I am hoping you guys can shed some light on this for me.

    When discussing objects moving an relativistic speeds, its often mentioned that as an object approaches the speed of light, it gains mass.
    My question is: is this mass real? If you somehow managed to impart enough energy on a probe to move it fast enough that it has the mass of a star, would that probe have the same gravitational pull of a star? Or is the increase in mass simply something we use to discuss how much kinetic energy the object contains?
     
  2. jcsd
  3. Oct 24, 2016 #2
    That depends on the definition of "real". It is as real as any other measurable quantity.

    There is no reasonable answer because the source of gravity in GR is not mass (no matter wich kind of mass) but the stress-energy-tensor. Depending on the circumstances the probe can have the gravity of a stars or not.

    In relativity it is in fact a measure of the energy. In it's original meaning it is a measure of the inertia.
     
  4. Oct 24, 2016 #3

    DHF

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    Thank you very much for the clarification.
     
  5. Oct 24, 2016 #4
  6. Oct 24, 2016 #5

    DHF

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    Thank you, reading it now.
     
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