Aristillus is a prominent lunar

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 crater ...

that lies in the eastern Mare Imbrium. It was named after Greek astronomer Aristyllus. Directly to the south is the smaller crater Autolycus, while to the southwest is the large Archimedes. To the northeast are the craters Theaetetus and Cassini. The rim of Aristillus has a wide, irregular outer

rampart Rampart may refer to: * Rampart (fortification), a defensive wall or bank around a castle, fort or settlement Rampart may also refer to: * "O'er the Ramparts We Watched" is a key line from "The Star-Spangled Banner", the national anthem of the ...

of ejecta that is relatively easy to discern against the smooth surface of the surrounding mare. The crater impact created a ray system that extends for a distance of over 600 kilometers. Due to its rays, Aristillus is mapped as part of the Copernican System. The rim is generally circular in form, but possesses a slight

hexagon In geometry, a hexagon (from Greek , , meaning "six", and , , meaning "corner, angle") is a six-sided polygon. The total of the internal angles of any simple (non-self-intersecting) hexagon is 720°. Regular hexagon A '' regular hexagon'' has ...

al shape. The inner walls of the rim have a

terraced In agriculture, a terrace is a piece of sloped plane that has been cut into a series of successively receding flat surfaces or platforms, which resemble steps, for the purposes of more effective farming. This type of landscaping is therefore ...

surface, and descend to a relatively rough interior that has not been flooded with lava. In the middle of the crater is a set of three clustered peaks, which rise to a height of about 0.9 km. In the northern outer

s of Aristillus is a

ghost crater A palimpsest , in planetary astronomy, 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 ...

remnant. This is the protruding rim of an old crater that has been almost completely submerged by the

lava Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or un ...

flows of the surrounding Mare Imbrium. The southern end of the rim has been covered by the ejecta from Aristillus. Along the eastern inner wall and rim is an unusual narrow ribbon of dark material. English progressive rock band Camel named the first song on their album '' Moonmadness'' after the crater. Science fiction author Travis J I Corcoran set much of his first novel, '' The Powers of the Earth'', on and under Aristillus.

Satellite craters

By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Aristillus.

Satellite craters

References

Sources

External links