something I've always wondered about

"dave blacker" wrote in message
m...
If the Universe is expanding, then all the galaxies must be moving
away from one another.

So how come there are such things as 'colliding galaxies'?

I think I remember on a Sky at Night show they said M31 and our own galaxy
will one day pile into each other. You should also remember that the images
of galaxies we see colliding actually took place hundreds of thousands of
years ago. We are looking into the past all the time.

Martin