cosmology question

[dolfanjack]

I have been watching the history channel today and the programs where about the cosmos and there is a concept I don’t understand and maybe someone here can help. After the ‘big bang’ the universe is expanding and all the galaxies are moving away from us and away from each other, I get that. Another episode discussed galaxies and explained that many collided with each other including our own. So, may question is if the universe is expanding and galaxies moving away from each other how can some of them also collide? Has dark mass caused some of their paths to move out of a straight line? Just something I was wondering with no one I could ask personally. Thanks, Jack

 

[Neal]

I'm not sure I entirely understand what you are asking, but here's my 2 cents. There are so many galaxy's out there of different sizes, every one of them is moving in some direction. Some are moving at different speeds than others and with so many out there collisions are bound to happen and have happened.

In a few thousand / million years we will be able to look up at the sky and see nothing but black intersteller medium because ever star and galaxy will be so far away from each other.

hubblesite.org is an amazing site if you are interested in the cosmos. There is currently a video on the front page called "cosmic collision". I didn't view it but it sounds like it may have something to do with your post. There is also a link to the "Tonight's sky" video that they update every month. It tells you what to look for as far as planets, stars, galaxy's, and whatever during the month.

 

[fhintz]

I'm not particularly knowledgable about these things . but I believe the answer roughly is that, while the universe is expanding, galaxies are not necessarily all moving out at the same speed, as various gravitational pulls slow them down and speed them up. Although, I do seem to recall hearing somewhere that the majority of collisions happened a long time ago when the universe was much smaller and denser.

Just my quick, off the top of the head answer. I'm sure there's some great websites out there on it.

Frank

 

[Angi]

HaHa I read cosmetology and thought cool a topic I know something about. Sorry Jack I thought I could help you, but I guess not LOL!