Planet
Mercury ☿
The smallest planet and the closest to the Sun. It never strays far from the Sun in our sky, so look low in the west after sunset or low in the east before dawn around its greatest elongations.
| Diameter | 4,879 km |
|---|---|
| Mean distance from the Sun | 0.387 AU (58 mln km) |
| Rotation period | 58.7 days |
| Orbital period | 88.00 days |
| Known moons (2025) | 0 |
| Symbol | ☿ Astronomical symbols |
| Naked-eye visible | Yes |