I have very little knowledge of physics so the simpler you can keep your replies the better for me. Newton put forth a gravity theory that essentially said that there is a force that pulls on us to keep people on the earth and this is gravity. Einstein came along and included in his theory of relativity that there is not a force that pulls on us but that because massive objects such as the earth bend/warp space that there is no pull on us but space is pushing us toward the earth. I'm not generally a skeptical person and so put it to my lack of knowledge as the reason I don't really believe space is pushing me toward the earth. But I am not here to argue that Einstein is wrong but to understand this part of his theory better. Did Einstein's theory about gravity make Newton's obsolete and so no longer valid nor used? Are there other theories on what the source of gravity is? Who is it that first thought that everything with mass has gravity?