Mercury
The smallest planet and the closest to the Sun, a cratered world of extreme temperature swings.
See Mercury in the 3D solar system →Mercury at a glance
- Distance from Sun
- 0.387 AU
- Radius
- 2,439.7 km
- Day length
- 176 days
- Year
- 88 days
- Moons
- 0
- Mean temperature
- 167 °C
- Surface gravity
- 3.7 m/s²
- Mass
- 0.055 × Earth
About Mercury
Mercury is the smallest planet in the solar system and the nearest to the Sun, orbiting at an average of about 58 million kilometres. With almost no atmosphere to trap heat, it swings between roughly 430 °C in daylight and −180 °C at night — one of the largest temperature ranges of any planet.
A single day on Mercury (sunrise to sunrise) lasts about 176 Earth days, longer than its 88-day year. Its grey, heavily cratered surface looks much like our Moon, a record of billions of years of impacts.
- Smallest planet in the solar system
- Closest planet to the Sun
- A day lasts longer than its year