Here are some sites and videos to help you with your research into Space.  There are more sites available on the Science Resources tab under Space and Our Universe.

Here is a video that helps show some size comparisons.  

Let Bill Nye give you a demonstration of the scale of our solar system.

Gravity - Use the links (attached to the questions) to help you find some of the answers for which you are looking.

Why don't we crash into the sun?


Why do the planets go around the sun?

The Milky Way Galaxy - Use the following links to help you understand where we are located in the Milky Way Galaxy.

Enchanted Learning's version

Astrodigital's information

Universe Today