My dad's really into astronomy and cosmology... sometimes some of the things he says are pretty woo, but overall he just likes reading popular science books on the topic.
Anyway, he insists that every point in the universe is moving away from every other point in the universe. I thought this sounded plausible, except I was wondering... on what scale? Would that apply to the cells in our body, or is each astronomical mass one of those "units" moving away from each other?
He tried to use this to refute that the Milky Way and Andromeda Galaxy would ever collide, even though as I understand it, that's a scientific fact. Can somebody set me straight on this?