Light and energy

[astrocuriousstudent]

The other day I was doing some reading, and I came across an article that said something about a spot in space, a rather large spot actually. It contains nothing, an 8billion light-year long abyss of nothing. I also read, in the same article, that light will lose its enegy faster in a vacuum with no matter whatsoever there with it. Is this true? I understand that light is basically energy and it is basically a wave, like sound almost, only in that it is a wave. so it only makes sense that it would lose energy, but how can something that I have been told time and time again that it isnt made up of anything with mass, how can that be affected by the lack of matter around it? I'm no astrophysics major, so if this seems like a dumb question, tell me.