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How are Mercury’s craters different from craters on the Moon?
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Mercury
Mercury as seen by the Messenger probe, January 14, 2008. This image shows half of the hemisphere missed by Mariner 10 in 1974–75 and was snapped by Messenger's Wide Angle Camera when it was about 27,000 km (17,000 miles) from the planet.
While Mercury’s surface appears superficially similar to the Moon, its craters exhibit distinct differences due to the planet's higher surface gravity and proximity to the Sun.12
Key differences include:
- Ejecta Distribution: Because Mercury’s gravity is more than twice that of the Moon, material ejected during an impact travels only about 65 percent of the distance it would on the lunar surface. This contributes to the greater prominence of secondary craters on Mercury.1
- Structural Thresholds: The complex features associated with larger craters—such as central peaks, slumped walls, and flattened floors—appear in smaller craters on Mercury (starting at diameters of about 10 km) compared to the Moon (where they begin at about 19 km).1
- Formation Dynamics: Mercury’s craters are influenced by higher impact velocities, as objects in solar orbit move faster the closer they are to the Sun.1
Additionally, while both bodies feature intercrater areas, Mercury’s intercrater plains are significantly more pervasive than the light-colored plains found in the lunar highlands.2