Question

2 photons travel in opposite directions, what is the speed of one photon relative to the other in a vacuum?

Answer 1

what the heck is a photon?

Answer 2

in laymen terms,
a photon is a particle of light, its also a wave

Answer 3

Both travel at c.

Answer 4

C is right, I think... also interesting to think of the apparent speed of one photon from the perspective of the other

Answer 5

... in every reference frame.

Answer 6

hm... gremlins in the web server... my post above was from 10-15 min ago, just appeared now. odd..

Answer 7

I agree it's C in every frame, I just think it's interesting :)