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.
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