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Does light continue to travel through space after its source is removed?

  1. Oct 26, 2014 #1
    Does light continue to travel through space after its source is removed?
     
  2. jcsd
  3. Oct 26, 2014 #2

    jedishrfu

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    yes it does.
     
  4. Oct 26, 2014 #3

    Drakkith

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  5. Oct 26, 2014 #4

    Nugatory

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    Here's an easy but pretty good analogy: I throw a stone into a quiet pond. The ripples spread out in a circle, and they will keep on propagating long after the stone has sunk to the bottom and is no longer disturbing the surface of the water.
     
  6. Oct 26, 2014 #5

    NascentOxygen

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    Fortunately for astronomers, it does. :cool:
     
  7. Oct 26, 2014 #6

    sophiecentaur

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    It never looks back.
     
  8. Oct 26, 2014 #7

    NascentOxygen

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    Yet it does reflect.
     
  9. Oct 26, 2014 #8

    sophiecentaur

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    And it gives a wave as it goes past.
    :D
     
  10. Oct 26, 2014 #9

    NascentOxygen

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    and if not going past, it gives a standing wave.
     
  11. Oct 28, 2014 #10
    Yes it does!!!!
    so probably, when you are observing a star thousands of lightyears away, you see how it looked thousands of years ago.

    That start could be fizzled up, and dead, and you don't even know
     
    Last edited by a moderator: Oct 28, 2014
  12. Oct 28, 2014 #11
  13. Oct 28, 2014 #12

    Drakkith

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  14. Oct 28, 2014 #13

    sophiecentaur

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    . . . . the same as the familiar sampling scope technique, which uses picosecond sample pulses to plot the voltage variation in a repeated waveform. Even more than that, he seems to be saying that the process is repeated many times, to achieve a sufficient exposure at each position of the pulse. because the actual energy admitted in a single fs sample is so incredibly low. Fair dooz. It's still pretty clever and produces an interesting insight into the progress of the light through (and also back through) that bottle.
     
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