"Richard Dickison" wrote in message
...
Why are most galaxies and solar systems 'flat'? If there is a cloud of
dust/gas that starts to coalesce around a localized density in the middle
of
the dust/gas, it seems it would attract from all 3 dimensions equally. But
galaxies and solar systems attract primarily in a single plane. What
happened to all the debris above/below the plane?

I understand there will probably be an unequal distribution of matter
surrounding the central object and there will consequently be a resultant
angular momentum after a while. But that doesn't seem to explain why
there
still isn't debris spiraling in from above/below the primary plane.

I also think that Centripatal force would play a part here. Any Galaxy
(like ours) that spins around a central point will tend to spread it's mass
out along the plane of the spin motion. I understand that calculating the
rate a Galaxy turns is one method used to calculate it's mass?

Martin