[mrlala]

Does that mean like, all the time?

For example.. if I'm looking at a star, and thinking it's the 'same' photon that came off of that star billions of years ago... that might be true in the vacuum of space, but since it's passed through the medium of the atmosphere, does that mean it's constantly been absorbed/new photons being emitted?

[empath75]

It’s not even true in the vacuum of space. It might have been created and annihilated billions of times on the way.