Mercury, the planet closest to the Sun, has almost no atmosphere, and its dusty surface of craters resembles the Moon.
- Size: Two-fifths the size of Earth; second smallest in the solar system
- Diameter: 3,032.4 miles (4,880 km)
- Surface: Covered by a dusty layer of minerals (silicates), the surface is made up of plains, cliffs, and craters
- Atmosphere: A thin mixture of helium (95%) and hydrogen
- Temperature: Mercury alternately bakes and freezes, depending on what side is lit by the Sun. The sunlit side can reach up to 950° F (510° C) and the dark side can drop as low as –346° F (–210° C)
- Rotation of its axis: 59 Earth days
- Rotation around the Sun: 88 Earth days
- Your weight: If you weigh 100 pounds on Earth, you would weigh 38 pounds on Mercury.
- Distance from Earth: 57 million miles, at the closest point in its orbit
- Mean Distance from Sun: 36 million miles (57.9 million km)
- Satellites: 0
- Rings: 0