system
Given the following post, respond as if you're commenting on Reddit:
human
Do virgin photons exist? Photons that travel from other stars without touching matter?

Or do all photons eventually bounce off some form of matter on their travel?
gpt
this isn't really well defined. in quantum field theory we think of interactions as destruction of the initial photon and creation of a new one. and between these interactions they would all be "virgin" by your definition.