Planet
Mercury
The closest planet to the Sun and the smallest. Its cratered surface resembles the Moon; because of a 3:2 spin–orbit resonance one Mercury day lasts two Mercury years.
| Type | Planet |
|---|---|
| Parent body | Sun |
| Radius | 2,440 km · 0.383 R⊕ |
| Mass | 3.301 × 10²³ kg · 0.0553 M⊕ |
| Mean density | 5.43 g/cm³ |
| Surface gravity | 3.7 m/s² · 0.38 × Earth |
| Escape velocity | 4.25 km/s |
| Rotation period | 58.7 days |
| Mean distance from the Sun | 0.387 AU (58 million km) |
| Eccentricity | 0.206 |
| Orbital period | 88 days |
| Class | Terrestrial, cratered |
| Surface temperature | 100–700 K |
| Moons | 0 |
Through a telescope from Earth
Moons and companions
- BepiColombo Spacecraft