Located on Jupiter's moon Callisto, Valhalla (/vælˈhælə/ val-HAL-ə)[1] is the largest multi-ring impact crater in the Solar System. It is named after Valhalla, the hall where warriors are taken after death in Norse mythology.
Valhalla consists of a bright central region 360 km across, an inner ridge and trough zone, and striking concentric rings extending up to about 1,900 km from the center.[2] Several large impact craters and crater chains are superimposed on Valhalla. The multi-ring system may have formed as semi-liquid or liquid material underlying the brittle lithosphere punctured by the impactor slumped towards the center of the crater following the impact.[3]
Greeley 2000
was invoked but never defined (see the help page).Schenk1995
was invoked but never defined (see the help page).