I recently found out that gravity on any given planet is caused by the mass of the planet. I had always assumed that gravity on a planet was caused by the speed of rotation, orbit, proximity to the sun, and size of the sun. I began exploring why gravity didn't get stronger during its ellipse when it was closest to the sun, and less when it was far. It was googling that which lead me to realize the size of the planet was the cause of gravity. But I am wondering, does speed of orbit and rotation play any part of planetary gravity?