Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Is distant starlite coherant?

  1. May 7, 2013 #1
    by the time light from a distant star reaches us, lets say from Canopus, does the light become coherent?

    and if it is coherent, can you make an astrohologram?
     
  2. jcsd
  3. May 7, 2013 #2

    Simon Bridge

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

  4. May 9, 2013 #3

    Chronos

    User Avatar
    Science Advisor
    Gold Member
    2015 Award

    Perhaps you meant polarized instead of coherent. That too is essentially untrue. You can test this yourself by viewing stars through a polarized lens, then rotate the lens 90 degrees and see if the stars changes in brightness. Star light can be mildly polarized due to scattering by dust particles over vast distances and also by strong magnetic fields on the star.
     
    Last edited: May 9, 2013
  5. May 9, 2013 #4

    Simon Bridge

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    ... possibly just thinking of the light being parallel?
    @brianhurren: any of this useful?
     
  6. May 9, 2013 #5
    If two observers are near, the light rays from such a distance source may be considered as coherent because, the angle between the light rays is too small and negligible. Theoretically, this assumption is valid
     
  7. May 9, 2013 #6

    Simon Bridge

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

  8. May 10, 2013 #7

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    Saying that light rays are parallel does not mean they are coherent.
     
  9. May 10, 2013 #8
    Oh. Sorry. I thought any parallel rays in phase are coherent
     
  10. May 10, 2013 #9

    davenn

    User Avatar
    Science Advisor
    Gold Member
    2015 Award

    yes they are, but that wasnt in your statement earlier, you didnt mention anything about them being in phase

    Dave
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Is distant starlite coherant?
  1. Distant objects imaging (Replies: 11)

Loading...