Haushofer, danke sehr!
Now I quite understand the point that I firstly mentioned:)
I now remembered the answer to my second question.
It was on tip of my tongue and you helped me out. XD
According to Einstein's General relativity, gravity is known as a curvature of space-time fabric. I watched a video clip on youtube and it said that gravity is not really a force but a shape of space and time. Then here comes a question-if gravity is not a force and just a curvature of fabric of...