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Basic question about speed of light situation

  1. Mar 28, 2009 #1

    fluidistic

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    Hi,
    I've read for any object, no matter how fast its motion is, it will always be "hit" by light at the speed of light. Does this also apply for light?
    In other words : Say there's a photon going in a way and another photon is created to go in the same way, but about 5 seconds later. I guess the last photon won't reach the other one that is already 5 seconds ahead. It would only apply for objects going less fast than the speed of light, right?
     
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  3. Mar 28, 2009 #2

    DaveC426913

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  4. Mar 28, 2009 #3

    fluidistic

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    Thanks for clearing my doubt.
    EDIT: By the way I'm sorry I posted this question in a wrong section. I didn't know exactly where it'd fit better and I made a bad choice.
     
  5. Mar 28, 2009 #4
    You could be interested in this simple question: you are in a starship (let's call it ST1) travelling at 0.99c with respect to Earth (for example); another starship (ST2), faster than your, passes by you at 0.99995c. At which speed will you see ST2 travelling with respect to you?
    It could, maybe, amaze you that the answer is: greater than 0.99c.
     
  6. Mar 28, 2009 #5
    Another variation on the original question:

    Even if the second photon is released from a starship moving at, say 0.9c, the second photon will still never catch the first.....both move at c.

    And if your speed varies as you mopve toward some distant light signal, you will still measure it's speed as c but as your speed changes your will detect the light as different colors...that is, different wavelengths (or equivatenly, different frequencies)...This is like running into head seas in boat...as you go faster the apparent wavelength shortens (in time) and you start to hit peaks and troughs faster....
     
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