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Neith (crater)
Encyclopedia
Neith crater is a crater
on Jupiter
's moon
Ganymede
, the largest moon in the solar system.
Impact features like Neith have been called "penepalimpsests" by some investigators or "dome craters" by others and are considered to be transitional between craters and palimpsests. Palimpsests are bright, nearly circular patches that are believed to be remnant impact features. They occur also on Callisto, Ganymede's neighbor farther distant from Jupiter.
The most striking feature in Neith is a large, circular dome about 45 km in diameter. The dome is surrounded by a wreath of rugged terrain. The wreath does not represent the original crater rim but the rim of a large central pit instead. The rim itself is barely visible and is located along the outer boundary of a relatively smooth, circular area, assumed to be the crater floor, which in turn surrounds the wreath of rugged terrain. In some parts along the rim, inward-facing scarp
s may be seen. The rim is not circular but appears to be petal-shaped. Outside the rim, a continuous ejecta
blanket may be discerned.
The morphology of impact features such as Neith results either from the response of a relatively weak target material to a high-energy impact or from long-term viscous relaxation of the surface subsequent to impact.
Absolute ages derived from crater frequency measurements are model-dependent. In one crater chronology model, based on impacts dominated by asteroids, Neith may be old and very likely was formed during a period of more intense bombardment than today, about 3.9 billion years ago. In a different model, based on impacts preferentially by comets with a more or less constant impact rate, Neith may be only about 1 billion years old.
Impact crater
In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...
on Jupiter
Jupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...
's moon
Natural satellite
A natural satellite or moon is a celestial body that orbits a planet or smaller body, which is called its primary. The two terms are used synonymously for non-artificial satellites of planets, of dwarf planets, and of minor planets....
Ganymede
Ganymede (moon)
Ganymede is a satellite of Jupiter and the largest moon in the Solar System. It is the seventh moon and third Galilean satellite outward from Jupiter. Completing an orbit in roughly seven days, Ganymede participates in a 1:2:4 orbital resonance with the moons Europa and Io, respectively...
, the largest moon in the solar system.
Impact features like Neith have been called "penepalimpsests" by some investigators or "dome craters" by others and are considered to be transitional between craters and palimpsests. Palimpsests are bright, nearly circular patches that are believed to be remnant impact features. They occur also on Callisto, Ganymede's neighbor farther distant from Jupiter.
The most striking feature in Neith is a large, circular dome about 45 km in diameter. The dome is surrounded by a wreath of rugged terrain. The wreath does not represent the original crater rim but the rim of a large central pit instead. The rim itself is barely visible and is located along the outer boundary of a relatively smooth, circular area, assumed to be the crater floor, which in turn surrounds the wreath of rugged terrain. In some parts along the rim, inward-facing scarp
Escarpment
An escarpment is a steep slope or long cliff that occurs from erosion or faulting and separates two relatively level areas of differing elevations.-Description and variants:...
s may be seen. The rim is not circular but appears to be petal-shaped. Outside the rim, a continuous ejecta
Ejecta
Ejecta can mean:*In volcanology, particles that came out of a volcanic vent, traveled through the air or under water, and fell back on the ground surface or on the ocean floor...
blanket may be discerned.
The morphology of impact features such as Neith results either from the response of a relatively weak target material to a high-energy impact or from long-term viscous relaxation of the surface subsequent to impact.
Absolute ages derived from crater frequency measurements are model-dependent. In one crater chronology model, based on impacts dominated by asteroids, Neith may be old and very likely was formed during a period of more intense bombardment than today, about 3.9 billion years ago. In a different model, based on impacts preferentially by comets with a more or less constant impact rate, Neith may be only about 1 billion years old.