Dear all, I have a problem as follows:
The gravitational force of the Sun is spherically symmetric. Therefore, one may naturally conclude taht the motion of the planets should also be spherically symmetric. This would only the the case if the planets moved in circles on surface of spheres. J. Kepler discovered (1609), however, that planets move in ellipses not in circles, on fixed planes not spheres, with the Sun at a focus not at the center. Explain what vialates the symmetry in the motion of plannets.
Thank you very much.