- Diameter: 4879 kilometers
- Circumference: 15,329 kilometers
- Mass: 3.30 x 10^23 kilograms
- Volume: 6.083 x 10^10 cubic kilometres
It has a volume around 5.4% that of Earths. It has no moons. It is 0.39 AU from the sun. It’s year is 88 days long. The temperature ranges from -173 to 427 celcius. Gravity is 38% that of earths. No one knows who discovered Mercury. It is the second Densest planet behind Earth. It has the slowest rotation of all the planets. Since its discovery, only two spacecrafts have visited Mercury. In 1974 and 1975 the Mariner 10 flew by Mercury three times, mapping just under half of the planets surface. On August 3rd 2004, the Messenger probe was launched from Cape Canaveral Airforce Station.