posted on Aug, 18 2004 @ 11:05 PM
The expanding universe was just featured on the science channel last night. Apparently, there are a growing number of astrophysicists who believe in
eternal expansion, especially without being able to accurately explain the dark matter problem (or lack thereof, if I remember correctly).
As far as galaxies colliding even though the universe is moving continually outward, well, that's our old friend gravity. Galaxies themselves are
gravitically bound to each other in groups, such as our Local Group which includes the Andromeda galaxy and the Small and Large Megellanic Clouds. In
fact, current theory holds that gravity will eventually win out and the Milky Way and the Andromeda galaxies will one day face a collision of their
own. Many things can influence the way in which two objects interact gravitically, and there are also mitigating circumstances during galactic,
stellar, and intergalactic formation that influence precise direction and momentum. Imagine if you threw a perfectly round object into the air and for
whatever reason, it would continue in the same direction forever. Then wind, heavier elements in the air, and such begin to interact with it and
affect its trajectory. Same thing on a much larger scale happens in the cosmos. it is possible that some event in the distant past influenced the
trajectory of the galaxies in the universe, and coupled with gravity and other altering effects (super and hypernova explosions in the galaxy or
outside the galaxy, density and frequency of activity in the central Black hole,etc) can have their directions changed enough to send them on a
Am I rambling? Because I think I'm rambling.
your mileage may vary.