A planet���s period of revolution is the time it takes for one complete spin around the sun. This is different from a planet���s period of rotation, which is the spinning of a planet on its own axis.
Mercury is the nearest planet to the Sun. Ancient Assyrian astronomers knew about this planet, which has the name of the Roman messenger god. The surface temperature ranges between -173 and 427 degrees Celsius. Due to many impacts from comets and asteroids, Mercury has many craters. A famous crater due to its size is Caloris Basin, which is 1.550 kilometers. This planet has no moons.Learn more about Planets