zlacker

> It seems like the vast majority of photons would just fly through the universe without interacting with anything, unless there are other ways for photons to interact with matter besides being absorbed.

Maybe someone who actually knows will chime in, but afaik:

- Most light doesn't have a fixed frequency. If it did, it would have a fixed momentum, but then you would have no idea where it is! Instead it is some superposition of many frequencies. That could be part of the story.

- Light could be stopped by something other than absorption into an individual atom. Metals don't have discrete spectra.