Orbit around the Sun: Because Mercury is so close to the Sun, it has the smallest orbit of all the planets. Mercury’s year (the time it takes to orbit the Sun one time) is 88 Earth days long.
Rotation: Although Mercury goes around the Sun quickly, it spins very slowly on its axis — about 59 Earth days for every rotation.
Surface: Scientists believe that Mercury has a thin, rocky crust, with a large metallic core, probably made of iron, at its center. Mercury is covered with craters and has ice at its poles.
Atmosphere: Mercury has an extremely thin atmosphere of helium and hydrogen captured from the solar wind.
Temperature: On Mercury, you would either freeze or roast. The highest surface temperature is 870° F (466° C), while the lowest temperature is –300 °F (–184 °C).
Other information: The Mariner 10 spacecraft flybys of Mercury in the 1974-1975 greatly enhanced our knowledge of the planet.
Because it moves so fast around the Sun, early Roman skywatchers named Mercury after their speedy messenger god. To the ancient Greeks, Mercury is identified with the god Hermes.
You can get more facts on the planets in our solar system in each of the articles linked to below: