: If motion is relative the how do we know that space : is expanding rather than we are shrinking ???

Well, we can tell because those things reletively close to us, like the sun, planet and moons are not getting bigger than us. I mean, if we, as a solar system are shrinking, reletive to the rest of the universe, yes, than it is possible. But, if that is what is going on, then why are we the only one's who are shrinking? That would be a galactic, if not universal anomoly.

Branwyn