Why do galxies move at different speeds?

Question

If everything originated from the same explosion, shouldn't all matter be traveling at the same speed, and wouldn't this create a sphere of sorts, with nothing but space where the bang originated?

Answer 1

There are plenty of alternative explanations (more theories) to explain the current observations that our telescopes reveal. One person I really enjoy is James Hogan, He is a sci-fi writer but trained technically. He certainly has no more answers than others but he is excellent in digging up alternative explanations as to how the universe may have been formed. I liked his book "Kicking the Sacred Cow" in which he offers alternative ways to think about a wide variety of subjects.

Also he has a great website and newsletter, just google James Hogan and you can get there.

One of his favorite subjects is the possibility that electric and magnetic fields played a larger role in the formation of the universe than did gravity. Here is a speech (lecture) he gave recently.

http://www.jamesphogan.com/demostuff/Eglin/FTCE.pdf

I listened to Stephen Hawkings on TV once and he made a statement somehting like this, "IF we are interpreting the red shift data correctly and IF general relatively is true than the big bang is feasible."

Seems to me that the two "IF's" leave no doubt that the fat lady hasn't sung yet. In other words, the answers aren't easy and I doubt that we have scratched the surface on many of these subjects.

Another answer on Y! stated it this way, "It isn't something that we should feel obligated to believe or not believe, to know or not to know, it is something we should try to understand."

And my two favorite humbling quotes from Albert Einstein himself:

1. I only had two ideas in my life and one of them was wrong.

2. Mankind does not know one thousandths of one percent about anything.

Lee Smolin's book, "The Trouble With Physics" is an eye opener also.

Answer 2

Ah...these are the questions that keep astronomers and astrophysisists up at night.
So far in super computer models of the big bang explosion, debris does NOT go out in a uniform manner.There are clusters of debris in some places,and no debris in others.
Also the matter at the farthest reaches of the universe (away from a central origin) seems to be moving FASTER than that that is more central.Explanation? Dark matter.