Main Question or Discussion Point
Hello, I would like to ask why if the Earth rotate around the Sun in circle orbit, it must have an kinetic energy equal to negative half of potential energy it has at anytime rotating round the sun, which Ek = -Ep/2 ! If this situation cannot be achieved, our Earth will move in a new ellipse orbit round the Sun. I read this article from a Chinese website, just troubling why Ek = -Ep/2 for circle orbit to be formed. Hope can get perfect answer...