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Quick question about light

  1. Apr 20, 2006 #1
    I know photons are massless, but is it possible at all for them in the form of say a laser to distort the curvature of space in the same way as an object with mass would? And if so is there any way to measure how much?

    Many thanks in advance.
  2. jcsd
  3. Apr 20, 2006 #2

    Doc Al

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    Yes, because photons have energy. In General Relativity, the source of gravity (and space-time distortion) is not mass, but energy (really the stress-energy tensor).
  4. Apr 20, 2006 #3
    Situation: i am travelling at 99,999....etc. speed of light and my mass is about 5000% my real mass. so, my gravitational distortion is 5000% more deeper than the stationary condition.

    but, as you assume, it's energy that makes the grav field, but i have an incredible cinetic energy (K=1/2mv²/gamma), and the distortion that it produces should grow if i also consider the distortion of my mass (not rest mass...the other i don't know the name) so my grav field is more than i aspect or there is something strange in your quote?
  5. Apr 20, 2006 #4


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  6. Apr 20, 2006 #5
    :uhh: Probably should've put a disclaimer about my poor maths in the first post. That article went way over my head:tongue2: ...

    Ok now simple energy I can understand (E=MC^2 can do that), but whilst I can understand that working for a single photon, can it work for a laser? If not, what I need is something where you can input say the diameter and length of the laser (plus energy at the target) to work out its equivalent mass (if that makes any sense at all :tongue: ). Damn I wish I could do maths better :( .
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