Facts about Callisto's Impact Basins
- 09
Mapping data from NASA's Galileo spacecraft reveals that Callisto's impact basins formed in a target of layered water ice and rock, with basin depths reaching 25 kilometers below the surface.
- 08
Callisto's oldest impact basins exhibit degraded morphologies with subdued rim topography, while younger basins retain sharp crater walls, demonstrating how thermal creep in the icy crust progressively smooths surface features over geological timescales.
- 07
Roughly 40 percent of Callisto's surface displays ejecta blankets from impact basins, with material scattered hundreds of kilometers from crater rims across the moon's ancient terrain.
- 06
Callisto's heavily cratered surface shows virtually no evidence of geological activity, preserving impact basins essentially unchanged for over 3.5 billion years due to its frozen, geologically dead interior.
- 05
Callisto's Valhalla impact basin created shock waves that traveled across the moon's surface, producing concentric fracture patterns visible across nearly half the satellite's diameter.
- 04
Impact basins on Callisto preserve a geological record spanning over 4 billion years, with crater density variations revealing that heavy bombardment continued long after the Late Heavy Bombardment period ended on inner solar system bodies.
- 03
Ancient multi-ring basins on Callisto lack the central peaks common to younger impact structures, indicating that viscous relaxation of the icy crust erased topographic relief over billions of years.
- 02
Callisto's impact basins display concentric rings extending outward from central peaks, with the Adlinda basin showing up to seven distinct circular ridges spanning over 1,200 kilometers.
- 01
The Gilgamesh impact basin on Callisto spans approximately 1,620 kilometers in diameter, making it one of the largest impact structures in the solar system.