system
Given the following post, respond as if you're commenting on Reddit:
human
Where do photons of light go?

I was watching the episode of Deeper, Deeper, Deeper Still of Cosmos and during it they kept mentioning photons of light. It got me thinking about how things absorb light allowing us to see different colors and stuff. 

So where exactly do the photons of light that initially bounce of off "things" and into our eyeballs end up? I've seen multiple diagrams showing the light bouncing or refracting off of a material and then into the retina or cornea (can't remember which) of our eyes. If it does this, is that the end of the road for a photon? Our eyes? Or does it go through our eyes and continue on into space?
gpt
The "end of the road" is when they are converted into another form of energy.  This could be heat when absorbed by a non-reflective surface, or the movement of an electron (photosynthesis and photoelectric effect).

When light hits the retina in your eye, a type of molecule known as a "chromophore" absorbs certain frequencies of light and this absorption causes an electron to move to an excited state.  

If the photon continued into space, that would mean it was not absorbed, and thus could have had no effect on your eyes or body.  (think radio waves - they pass right through you.)