I'll give you a four on relevance, but just because of the boldness of yours!
I see where you are going, but the Moon actually isn't big when compared to other things in outer space, like planets, earth!
So ok you could say that's the moon, and it's small and everything around it is big!...
Ok, ok... five it is!

A very small picture of a very big thing!

So small Moon in so big Universe?

Are you going for big sky? Big universe? Big black space around the little moon? I'm not getting it.

A big night sky? The centered composition doesn't say much for me.

big or little??

Ironic, intellectual, commentary on the theme. High marks.