Quote Originally Posted by Kalopin View Post
No, gravity alone does NOT keep us in orbit. If there was only gravity everything would form one single mass objectand be "stuck" together.There must also be repelling forces!

Science 101.
I'll second Strange's question...where do you get this stuff? Repulsive forces are absolutely not necessary for things to orbit. Simple inverse squared attractive gravity is sufficient for a very accurate model of the solar system, and certainly does not lead to everything getting "stuck together".