Expert: Courtney Seligman - 6/10/2010

Question
Hey Courtney,
I'm doing a culminating activity for my astronomy class and I'm having a little trouble answering a few questions. Please help me with any of the questions you can answer. Thanks! :)

1. If everything is moving away from us, does that mean that we are in a special place in the universe? Explain.

2. How does Hubble's Discovery of the expansion of the universe imply that there was a Big Bang?

3. Would a larger value for the Hubble Constant make the universe older or younger?

Answer
I'm not supposed to answer homework questions, but I can give you a couple of brief comments, and a link to a page which may be of some use.

First, as the page will explain, the Hubble age is inversely proportional to the Hubble constant, so a larger constant would make the Universe younger.

Second, there is no center to the Universe, but the fact that it expands in all directions makes it appear that you are at the center, no matter where you are. So there is an illusion of being at the center, but it is only an illusion.

The page I'm referring you to is a "quick and dirty" summary, covering much of the astronomy (and the history of the astronomy) involved in discussing the expansion. The first half should take care of your second question. Its address is http://cseligman.com/text/galaxies/universe.htm

If you have any questions about specific topics involving this material which you would like explained in more detail, I'll be happy to answer them; but as noted above, I can't just provide you with an answer.