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Star light from a dead star ?

  1. Nov 20, 2009 #1
    I understand that a great number of star's we see are no longer there (now dead)we are just seeing the light traving from them over the vast distense of space, Question
    If I were looking in to the sky at night and seeing start light from a now Dead star and someone else (you) at the same time, was in the place that was once occupied by that star would they (you) be able to see the same star light moving away from them as i'm seeing on eath . IE would they be able to see the back of the light ??

    Star->->->-Light->->->->-Me
    You->->->-Light->->->->-Me
    Just a question For a friday
     
  2. jcsd
  3. Nov 20, 2009 #2

    Nabeshin

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    Science Advisor

    Think about light as individual photons for a second. The only way you see light is when photons hit your detector, be that a telescope, the back of your eye, or some other device you've concocted. So ask yourself: How could the observer on the star possibly see the light if the photons were traveling away from him? He wouldn't, because they would never come in contact with his detector.
     
  4. Nov 20, 2009 #3
    If a ball flies away from you, can it hit you in the head? It needs to bounce of something to come back. Same with light. But if you are on the our Sun, and you manage to shut it down instantly, you would see Earth for 16 more minutes.
     
  5. Nov 20, 2009 #4
    suppose the dying star collapsed in on itself and made some sort of black hole, and the last photon never made it past the event horizon. If you were still standing at the center of where the star once was (now a black hole) would you be able to see the photon that never escaped and is now getting infinity stretched due the black hole ? or would you forever be beyond the range of the stretching photon and thus never detect it?
    basically ... can the photon catch up to your eye within the black hole since it started a little ways off therefore giving you a "head start"?

    assuming your not crushed into a singularity
     
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