Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: barbs7777 on 06/02/2011 18:30:02

Title: Are our galaxy and solar system expanding?
Post by: barbs7777 on 06/02/2011 18:30:02

barbs7777 asked the Naked Scientists:
   
Since the universe is expanding, where is the middle of this universe (or would that be called the origion of the big bang?)

Is our galaxy expanding also?

Then, is our solar system expanding within itself?

What do you think?

Title: Are our galaxy and solar system expanding?
Post by: graham.d on 06/02/2011 18:59:32

There is no middle to the universe. It is a 4 dimensional space. An analog is to think that you are a two dimesional being in a 3D world but are confined to the surface of a balloon that is being inflated. You see objects around you moving away but there is no point in your "world" (on the surface) that is the origin of this expansion.

Our galaxy is not thought to be expanding as such, even though the big picture shows space time expanding. You could think of whole galaxies as pieces of dust in a huge room which is expanding. The mechanisms for expansion are a much larger scale than the size of galaxies which are held together by gravity which wins at this local level.