Expert: Steven LJ Russo - 11/18/2007

Question
Hello,

  I have always been so much interested to know so much about the universe, infact all about the universe, but never got time or the opportunity to research. I have finally decided to spend atleast some time researching no matter what. I have been having some basic questions which I tried to google but never came across any explanation which really made it clear enough to me. So here are my questions:

1) Why do moon revolve around the earth? I mean why does it not fall on the earth? I understand due the the gravity?

2) Similar question: why does earth revolve around the Sun? why does it not fall?

3) Is there some place above the earth where somehow my body can be placed by which I will also revolve around earth? Or maybe moon? Will I feel the movements?

Regards
Bhavesh

Answer
Regardless of what object it is, there is a place above a planet, star, etc, where you can place an object where it will go fast enough to orbit, but not be pulled in to the body.  If it goes too slow, it will be pulled in by gravity.

So, Yes, there is a point where you could orbit an object, and not "fall" in.

Steve