A palimpsest , in

planetary astronomy Planetary science (or more rarely, planetology) is the scientific study of planets (including Earth), celestial bodies (such as moons, asteroids, comets) and planetary systems (in particular those of the Solar System) and the processes of their fo ...

, is an ancient crater that has been degraded over time. They may also be referred to as "ghost craters", "degraded craters", "buried craters", or "pathological craters". Palimpsests have been identified on Mercury, the Earth, the Moon, Mars, Ganymede, Callisto, and possibly even Titan. On Mars, these features are morphologically described as craters that are "flat-floored, rimless, extremely shallow, without central peaks, and would probably represent what remains after erosion." On an

icy moon Icy commonly refers to conditions involving ice, a frozen state, usually referring to frozen water. Icy or Icey may also refer to: People * Icy Spicy Leoncie, an Icelandic-Indian musician Arts, entertainment, and media Music * ICY (band), a voca ...

of the

outer Solar System The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar S ...

, a palimpsest is a crater whose

relief Relief is a sculptural method in which the sculpted pieces are bonded to a solid background of the same material. The term '' relief'' is from the Latin verb ''relevo'', to raise. To create a sculpture in relief is to give the impression that th ...

has disappeared due to creep of the icy surface ("viscous relaxation") or subsequent cryovolcanic outpourings, leaving a circular albedo feature, perhaps with a "ghost" of a rim.

Icy Icy commonly refers to conditions involving ice, a frozen state, usually referring to frozen water. Icy or Icey may also refer to: People * Icy Spicy Leoncie, an Icelandic-Indian musician Arts, entertainment, and media Music * ICY (band), a vocal ...

surfaces of natural satellites like

Callisto Callisto most commonly refers to: *Callisto (mythology), a nymph *Callisto (moon), a moon of Jupiter Callisto may also refer to: Art and entertainment *''Callisto series'', a sequence of novels by Lin Carter *''Callisto'', a novel by Torsten Kro ...

and Ganymede preserve hints of their history in these rings. A typical example is Memphis Facula on Ganymede, a 340 km wide palimpsest.

References

{{Reflist, refs = {{cite journal , title=Characterization of palimpsest craters on Mars , last1=Barata , first1=T. , last2=Alves , first2=E. I. , last3=Machado , first3=A. , last4=Barberes , first4=G. A. , journal=Planetary and Space Science , volume=72 , issue=1 , pages=62–69 , date=November 2012 , doi=10.1016/j.pss.2012.09.015 , bibcode=2012P&SS...72...62B {{Cite book , last = Harland , first = D. M. , title = Jupiter Odyssey , publisher = Springer Praxis , edition = 1st , date = 2000-11-10 , pages = 448 (see pp. 136–137) , url = http://google.com/books?id=QtxVTDhrRAEC&pg=PA136 , isbn = 978-1-85233-301-0 , oclc = 44461919 Space science Planetary geology Surface features of bodies of the Solar System Impact craters

See also

References