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

B Doubts about Light...

  1. Dec 27, 2017 #41

    Dale

    Staff: Mentor

    A thread derail has been deleted and the thread is reopened
     
  2. Dec 31, 2017 #42
    I think I might have explanation of "why moving atoms preferentially emit forwards" without the help of quantum theory.
    This is because if we suppose the filament is formed of multiple small elements, then firing the light by the rear element should be seen first before the near element by the ground watcher. This causes constructive interference with angle in the direction of the motion.
    see a similar concept: https://en.wikipedia.org/wiki/Phased_array_ultrasonics
     
  3. Dec 31, 2017 #43

    PAllen

    User Avatar
    Science Advisor
    Gold Member

    Aberration can increase or decrease apparent brightness over and above any Doppler effect. Moving towards a light source which emits spherically symmetrically, aberration concentrates more of the solid angle of emission towards the line of relative motion. Blueshift adds to this effect, leading to extreme brightening, called relativistic beaming. The reverse happens moving away from spherically symmetric light source, so that any light source you are directly moving away from sufficiently fast becomes undetectable in practice. Since I am only discussing inertial motion. this has nothing to do with a Rindler horizon.

    The impact of aberration on observed intensity is a very well known phenomenon in astronomy.
     
  4. Dec 31, 2017 #44
    So, if my explanation of the aberration concentrated beam, 3 posts back, is right, what makes it is still valid for a hypothetically single source element, say one atom radiating light?
     
  5. Dec 31, 2017 #45
    I hope my consideration is answered before the thread is closed for moderation.
     
  6. Dec 31, 2017 #46

    PAllen

    User Avatar
    Science Advisor
    Gold Member

    Which post should I look at? You didn't give a link or a post number.
     
  7. Dec 31, 2017 #47
    42 and 46

    [Moderator's Note: Several posts were deleted after this post was made, so the post numbers above are no longer correct.]
     
    Last edited by a moderator: Dec 31, 2017
  8. Dec 31, 2017 #48

    PAllen

    User Avatar
    Science Advisor
    Gold Member

    I don't see #42 as much related to aberration. Aberration does not involve interference; it is, if you will, a geometric optics phenomenon, or, more generally, just a question of how Lorentz transform affects angles.
     
  9. Dec 31, 2017 #49

    PeterDonis

    Staff: Mentor

    Thread closed for moderation.

    Edit: The thread has run its course and will remain closed.
     
    Last edited: Dec 31, 2017
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook