Kepler’s Law and Gravitation

Each planet orbits the Sun following an ellipse with the Sun at one focus and nothing at the other focus. Distances from the Sun vary when planets are orbiting. Kepler said that a planet covers the same area in the same time. It sweeps out equal areas in equal times so must go a bigger distance when it is closer to the Sun, and a smaller one when it’s farther, so the area stays the same. Therefore each planet travels faster when it is nearer the Sun than when it is further.