mean distance from sun: 57.8 million km (0.39 AU)

period of revolution: 88 days

Rotational period: 58.6462 days

Tilt of axis: 0.00^o

mass: 0.33*10²⁴ kg (0.38)

mean diameter: ~4,400 km (0.35)

mean density: 5.43 g/cm³ (0.99)

moons: 0

elements and combinations to be found: silicate, iron, nickle

Atmospheric composition Helium: 42% Sodium: 42% Oxygen: 15% Other: 1%

surface structure: rocky, craters

surface temperature: -170°C to 400°C

Mercury is the planet in our solar system closest to the sun. It has a core of iron and nickle that makes up 80% of the planet's diameter. The Caloris basin has a diameter of about 1300 km, and is 9 km deep.