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The light from a star

  1. Nov 26, 2009 #1
    What is different about the photons from a star compared to something man-made which allows it to travel so far?
     
  2. jcsd
  3. Nov 26, 2009 #2

    Garth

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    The star's bright!

    Garth
     
  4. Nov 26, 2009 #3

    Janus

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    In other words, there is nothing different about the photons themselves, it is just the sheer number of them emitted by the star.
     
  5. Nov 27, 2009 #4
    But then doesn't that imply that photons decay? If so then, shouldn't all photons decay at the same rate? Which means that the light from stars shouldn't be visible. Sorry, I'm a noob. I googled a lot of info but it's hard for me to find accurate and very specific answers to very specific questions. I appreciate any and all replies.
     
  6. Nov 27, 2009 #5

    Ich

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    No, they merely get http://en.wikipedia.org/wiki/Inverse-square_law" [Broken], lost in the universe.
     
    Last edited by a moderator: May 4, 2017
  7. Nov 27, 2009 #6
    Is the dillution rate constant?

    If not, then, would light from a flashlight have limited range because the photon dillution rate is much higher than the rate of the light from stars?
     
    Last edited by a moderator: May 4, 2017
  8. Nov 27, 2009 #7

    Ich

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    I don't know how a "dilution rate" should be defined. If you take a look at the link in my last post, you see that the photons simply spread over an increasingly large area as they gain distance from the star.
     
  9. Nov 27, 2009 #8

    sylas

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    "dilution rate" is simply a way of saying that something further away appears less bright, because there are fewer photons per unit area (or per eyeball) as the light spreads out over a larger area.

    There's no difference between man made photons and natural photons. They are all just photons.

    A Sun-like star appears no more and no less bright than a 3.8 x 1026 Watt light bulb.
     
  10. Nov 29, 2009 #9
    To answer your initial question nothing. There is no difference between sun made photons and flashlight made photons. They are both stable (do not decay). They both travel at the same speed c. They both just keep going until they hit something. Then they may be absorbed or scattered.
     
  11. Nov 30, 2009 #10
  12. Dec 2, 2009 #11

    Matterwave

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    Photons must be stable, else the Electromagnetic force would be limited in range...(IIRC)
     
  13. Dec 3, 2009 #12

    Chronos

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    Photons disperse and scatter, they do not become 'diluted' over time.
     
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