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Speed light travels on earth and in our solar system

  1. Aug 11, 2004 #1
    We know the speed light travels on earth and in our solar system, but if there is a universal speed max then one of two things must be true. One, light moves with its origanator's velocity and hence its own velocity to a subjective observer moving with the originator's velocity seems slower then the actual speed max. Say the sun is moving in any given direction at .25 of the max then light from the sun would be travelling at .75 max. Hence light moving from a star travelling at a slower velocity then ours would be faster then 'our' light. If it is faster it could reach us far sooner then we would expect it to and the ojects could be a lot closer, or inversly, a lot farther away if they are moving faster then us.
    Two, if light does not move with its origantor's velocity and its origanator is moving at .25 max then it would be warped in the same manner as the doppler effect. This too would alter the calculations of distances between stars.
    Since there is no absolute stationary point is it possible to know which of these hpothesis are true?
  2. jcsd
  3. Aug 12, 2004 #2


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    The second one is closer to the truth. All observers measure the same velocity of light, irrespective of the velocity of the source. Light is doppler shifted depending upon the velocity of the source. It is 'redshifted' (wavelength increases) if the source is receeding and is 'blueshifted' (wavelength decreases) if the source is closing.
  4. Aug 12, 2004 #3


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    What makes you think that either alters the measurement of the distance between stars?
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