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

Do photons bounce into each other?

  1. Aug 19, 2014 #1
    if photons bounce into each other at a frequent rate, and photons bouncing off of each other may result in large change in direction of motion... then why dont we see "junk" photons? photons that enter our eye not because they bounced off a surface, but instead bounces off of another photon?
  2. jcsd
  3. Aug 19, 2014 #2


    User Avatar
    Science Advisor

    Photons don't bounce into one another. They cannot interact with one another directly. They can only scatter off one another indirectly (c.f. Delbruck scattering).

    The term "collision" is often used in scattering theory but in that context "collision of particles" translates into "interaction of particles through some potential of finite range" so scattering doesn't necessarily entail an actual collision in the colloquial sense. It's a very poor but ubiquitous terminology.
  4. Aug 19, 2014 #3
    Not in the conventional sense. Having no mass, they do not collide as other particles would, especially if you look on the macroscopic level. They do interact, but remember that they are bosons, not fermions. They can, and do, occupy the same physical space as other photons.
  5. Aug 19, 2014 #4


    User Avatar
    Gold Member

    I found this an interesting question so poked around the internet a bit (acesuv, I encourage you to do a bit of your own research on questions like this) and found that you can even shoot laser beams through each other with basically no effect.
  6. Aug 20, 2014 #5
    Hmm under some conditions they could I guess. In this article http://phys.org/news/2013-09-scientists-never-before-seen.html researchers were able to create a "photon molecule" so I guess if you could get two of them you could get them to bounce off each other.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook