- Distance
- 0.39 AU
- Diameter
- 4,879 km
- Year
- 88 days
- Day
- 59 Earth days
- Moons
- 0
About Mercury
Mercury is a cratered, airless world only slightly larger than Earth's Moon. With no atmosphere to trap heat, its surface reaches 430 °C in daylight and plunges to −180 °C at night. Despite being so close to the Sun, permanently shadowed craters at its poles hold water ice. Mercury has an oversized iron core that makes up about 85% of its radius, and a weak magnetic field. A day on Mercury (sunrise to sunrise) lasts 176 Earth days, twice as long as its year.
- Fastest-moving planet at 47 km/s
- Largest temperature swing of any planet
- Visited by Mariner 10, MESSENGER and BepiColombo