Image courtesy of NASA / JPL-Caltec

Mercury, named after the ancient Roman God of commerce, is the closest planet to the Sun and also the smallest planet in our solar system. Mercury is a small and dense rocky planet without an atmospher. Mercury has extreme temperature variations. The planet has long days and short years as it orbits the Sun in just 88 days.

Mercury looks very similar to our Moon with great plains and cratered surface formed by impact. Like Earth it has an iron core but a weak magnetic field. Unlike Earth it has no satellites orbiting the planet.

Mercury has a very elliptical orbit around the Sun. At the closest point (perihelion) it's 46.000.000 km from the Sun, but at the farthest point (aphelion) it's 70.000.000 km from the Sun.

Missions to Mercury

Mariner 10 - United States - Launched november 3, 1973 Read more

MESSENGER - United States - Launched august 3, 2004 Read more


Radius: 2.440 km

Density: 5.427 g/cm3

Gravity: 3.7 m/s2

From Sun: 0.38 AU

Lenght of day: 58.65 Earth days

Lenght of year: 87.97 Earth days

Surface temperature: -173 to +427

Core temperature: ?

Composition: Silicates and iron