The closest planet to the Sun, Mercury is also the smallest (now that Pluto has been demoted to dwarf planet). Mercury is much denser than other objects (such as moons) of its size, probably because of a very large planetary core composed of iron. Mercury is a Terrestrial Planet.
Mercury is about 4880 kilometers (3000 miles) in diameter. In a spacefaring campaign, it may be useful to know that Mercury's escape velocity is 4.25 kilometers per second (2.65 miles per second), somewhat more than a third of Earth's.
Due to its position in the Sun's gravity well, Mercury is harder to reach than its distance would suggest.
Game and Story Use
- Scientific stations to study the Sun could be placed on Mercury.