For example i am standing and a beam of light is passing in front of me. I am able to see that beam of light so does it mean that photons are travelling in all directions other than the photons which are travelling in the beam of light travelling in front of me? And if the photons is travelling in all directions its brightness is lesser than the brightness of the direct beam of light right?


2 Answers 2


you see the beam of light because it lightens the molecules in the air. The photons you see have been diffused by the molecules of air. In the vacuum photons won't change of direction (they go at the speed of light) and you wouldn't see the beam passing in front of you.

  • $\begingroup$ then how are we able to see the light of sun in space? Are we able to see the sun's light because it releases photons in all directions? $\endgroup$
    – Bhavesh
    Mar 30, 2015 at 17:18
  • $\begingroup$ if you stare at the sun then the photons go directly in your eyes (in straight line). $\endgroup$
    – ceillac
    Apr 1, 2015 at 13:41

Well, photons behave both as a wave and as particles, and the photons in coming from the beam of light "enlighten" the particles in front of you.

  • $\begingroup$ Light does behave like a wave, but a "beam" is actually a wave with a main lobe and a small, narrow set of sidelobes. The "laser beam viewed from the side" cannot be explained by this, and furthermore the effect goes away in vacuum. Borilla's answer is right. $\endgroup$
    – MSalters
    Apr 1, 2015 at 23:32

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