Mercury

Mercury is the first planet from the sun, but it isn't the hottest. It is considered the smallest planet in our solar system.

Appearance
Mercury looks like a gray rock with a lot of craters, and it's too close to the sun to have ice or water on its surface. The reason it has so many craters is from meteor collisions. Meteors are chunks of space rocks that form when gravity pulls small pieces of matter into a large rock.

Moons
Mercury does not have any moons.

Facts
Mercury is tidally locked with the sun. It completes one orbit every 88 days, and completes a full rotation 58.5 days. Mercury does not have an atmosphere. Probes that have visited mercury include Mariner 10 and MESSENGER. Although Mercury is the closest planet to the sun, that doesn't make it the hottest. For instance, see Venus. And since it doesn't have an atmosphere, it is extremely cold at night there.