The planet Mercury is the closet planet to the sun. That means it’s really hot on Mercury! The temperature can get as hot as 750 degrees Fahrenheit and as cold as -328 degrees Fahrenheit. That is a very big jump in temperature! This temperature jump happens because Mercury is so close to the sun and because it has almost no atmosphere. An atmosphere is layers of gases that protect a planet from the sun rays and from outer space rocks. Mercury does not have enough gravity to hold an atmosphere. Without an atmosphere Mercury can get hit by asteroids, meteors, and comets. Most of the surface of the planet is hard, rocky, and full of craters or deep circular holes. In fact, Mercury must have been hit by something big to create the crater known
