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Another light question

  1. Jul 29, 2004 #1
    So, if the speed of light appears to reach the observer at the same time no matter the observers velocity, then does that mean that light from the nearest star reaches us just as quickly as light from the farthest galaxy?
  2. jcsd
  3. Jul 29, 2004 #2


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    I think you may have misread or misunderstood something. Light doesn't take the same amount of TIME regardless of the source. It has the same SPEED, regardless of the source. The constancy of the speed of light is one of the fundamental postulate of Special Relativity, NOT the constancy of the TIME that light travels.

    This correction should answer your question above.

  4. Jul 29, 2004 #3
    ZapperZ is right, light is emmited from a source, no matter what its inetrial frame is, at c. But if one source if further from the other, the closer sources light will reach us first. Now if you were in the frame of reference of the light, then it would all reach us at the same time, since at the speed of light, d becomes 0, and time becomes 0, so you can say that light is everywhere in the universe at the same time. But we do not live or can see the frame of reference of light, so using this explination is rather useless.
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