whilst space has no mass, it may be expanding because it is a finite amount of space, spreading out
How do we know that atoms are not expanding along with the instruments with which the are measured?

Antway, that is not so important to me as the Question I asked:

Im surprised by the fact that you are nonchalant about what happens to them (photons that is).

If reflected, they should be observable with telescopes which could mean that some distantly observed old stars are merely reflections of even older stars.

Also, there are many stars, which could mean such photon reflection that we would have to wear sunglasses at night.

Another possibility is that they disappear on contact, but that would break the conservation of energy law, I think.

"The written word is a lie"