Mercury, the smallest planet in our solar system, rotates very slowly, completing one full turn in approximately 58.6 Earth days. This slow spin means that a point on its equator moves at a relatively low speed.
How Fast Does Mercury Rotate?
Mercury's rotation is unique among the planets due to its slow speed and its orbital resonance with the Sun. Its rotation can be described in two primary ways: by its sidereal rotation period and its equatorial rotation velocity.
Key Rotation Facts for Mercury:
| Aspect of Rotation | Value |
|---|---|
| Sidereal Rotation Period | 58.646 Earth days (1407.5 hours) |
| Equatorial Rotation Velocity | 3.026 meters per second |
Sidereal Rotation Period Explained
The sidereal rotation period refers to the time it takes for Mercury to complete one full rotation on its axis relative to the distant stars. For Mercury, this period is 58.646 Earth days, which is equivalent to 1407.5 hours. This is significantly slower than Earth's 24-hour rotation. This slow rotation contributes to Mercury's extreme temperature variations between its day and night sides.
Equatorial Rotation Velocity Explained
The equatorial rotation velocity describes the speed at which a point on Mercury's equator is moving due to the planet's spin. For Mercury, this velocity is approximately 3.026 meters per second. To put this into perspective, this speed is roughly equivalent to walking speed. This is a direct consequence of its very long rotation period, even though Mercury is a relatively small planet.
This combination of a long rotation period and a relatively slow equatorial velocity defines how "fast" Mercury rotates.
