"Topquark" wrote in message
...
A program on the Science Channel last night talked about black holes in
the
center of galaxies. It also mentioned that the galaxy in Andromeda M31 is
moving toward us and will therefore collide with our galaxy some time in
the
future--They showed simulations. Is this true?

Probably not.

You can get the radial
velocity from the Doppler shift, but how can they know the angular
velocity?

Not sure about angular, but we certainly don't know about the transverse
velocity. Chances are we'll miss each other.

Isn't it more likely that it's just gravitationally bound?

Most likely it is, since we're both part of the local cluster.