Memphis Facula is a

palimpsest In textual studies, a palimpsest () is a manuscript page, either from a scroll or a book, from which the text has been scraped or washed off so that the page can be reused for another document. Parchment was made of lamb, calf, or kid skin an ...

, or "ghost crater", on Ganymede, the largest of the Jovian satellites. About 360 km across, it is situated in the southwestern part of

Galileo Regio Galileo Regio is a large, dark surface feature on Jupiter's moon Ganymede. It is a region of ancient dark material that has been broken apart by tectonism and is now surrounded by younger, brighter material (such as that of Uruk Sulcus) that ha ...

, a huge almost circular dark region in Ganymede's northern hemisphere. Although almost level today, it is a relic of a massive impact and once was a deep

impact crater An impact crater is a circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact craters ...

whose walls have slumped and its floor has risen isostatically, smoothing out the remaining

topography Topography is the study of the forms and features of land surfaces. The topography of an area may refer to the land forms and features themselves, or a description or depiction in maps. Topography is a field of geoscience and planetary sci ...

with slush. The morphology of the larger

palimpsests In textual studies, a palimpsest () is a manuscript page, either from a scroll or a book, from which the text has been scraped or washed off so that the page can be reused for another document. Parchment was made of lamb, calf, or kid skin an ...

like Memphis Facula suggests that Ganymede's icy crust at the time of impact was about 10 km thick and was penetrated by the impact, allowing the slush and fluid beneath to fill and level out the crater.

References

{{Solar System Surface features of Ganymede (moon)

See also

References