Planet 1 of 8
Mercury
The scorched speedster
The smallest planet and the closest to the Sun, Mercury races around its orbit faster than any other world while swinging between blistering days and freezing nights.
Quick facts
- Type
- Terrestrial
- Distance from Sun
- 0.39 AU
- Diameter
- 4,879 km
- Mass
- 0.055 × Earth
- Surface gravity
- 3.7 m/s²
- Day length
- 58.6 Earth days
- Year length
- 88 Earth days
- Moons
- 0
- Average temperature
- 167 °C
- Composition
- Iron core, thin silicate crust, almost no atmosphere
Fun facts
- A single Mercury day lasts about two thirds of its year.
- Its iron core makes up roughly 85% of the planet's radius.
- Temperatures swing over 600°C between day and night.
- Water ice hides in permanently shadowed polar craters.