Cayley is a small lunar

impact crater An impact crater is a depression (geology), depression in the surface of a solid astronomical body formed by the hypervelocity impact event, impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal c ...

that is located in a

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 Natural satellite, moon onto its surface. Lava may be erupted at a volcano or through a Fissure vent, fractu ...

-flooded region to the west of

Mare Tranquillitatis Mare Tranquillitatis (Latin for Sea of Tranquillity or Sea of Tranquility) is a lunar mare that sits within the Tranquillitatis basin on the Moon. It contains Tranquility Base, the first location on another celestial body to be visited by huma ...

. It was named after the 19th-century English mathematician

Arthur Cayley Arthur Cayley (; 16 August 1821 – 26 January 1895) was a British mathematician who worked mostly on algebra. He helped found the modern British school of pure mathematics, and was a professor at Trinity College, Cambridge for 35 years. He ...

. It lies to the northwest of the smaller crater De Morgan and the larger D'Arrest. West and slightly north of Cayley is Whewell, a crater of about the same dimensions. To the north is a linear

rille Rille (German for 'groove') is typically used to describe any of the long, narrow depressions in the surface of the Moon that resemble channels. The Latin term is ''rima'', plural ''rimae''. Typically, a rille can be several kilometers w ...

designated Rima Ariadaeus, which follows a course to the east-southeast.

Description

This is a circular, bowl-shaped formation with a small interior floor at the midpoint. (Small being relative to the overall diameter, as it occupies about one-fourth the total cross-section.) The sloping interior walls are relatively light in hue, having a higher

albedo Albedo ( ; ) is the fraction of sunlight that is Diffuse reflection, diffusely reflected by a body. It is measured on a scale from 0 (corresponding to a black body that absorbs all incident radiation) to 1 (corresponding to a body that reflects ...

as the surrounding terrain. However it is not nearly as bright as the slightly larger crater Dionysius to the east-southeast, and lacks a

ray system In planetary geology, a ray system comprises radial streaks of fine '' ejecta'' thrown out during the formation of an impact crater, looking somewhat like many thin spokes coming from the hub of a wheel. The rays may extend for lengths up to ...

. The smooth, rolling plains to the east of this crater are called the Cayley Formation. It is somewhat similar to the lunar maria, but has a slightly higher

and is overlapped at the eastern edge by the

. Lunar scientists suspect that this plain may have resulted from deposits of ejecta from the formation of large impact basins such as

Mare Imbrium Mare Imbrium (Latin ''imbrium'', the "Sea of Showers" or "Sea of Rains") is a vast lunar mare, lava plain within the Imbrium Basin on the Moon and is one of the larger craters in the Solar System. The Imbrium Basin formed from the collision ...

or Mare Orientale. (The most likely source is the

impact basin to the northwest.) Cayley is a crater of

Eratosthenian The Eratosthenian period in the lunar geologic timescale runs from 3,200 million years ago to 1,100 million years ago. It is named after the crater Eratosthenes, which displays characteristics typical of craters of this age, including a surface ...

age.The geologic history of the Moon

USGS The United States Geological Survey (USGS), founded as the Geological Survey, is an government agency, agency of the United States Department of the Interior, U.S. Department of the Interior whose work spans the disciplines of biology, geograp ...

Professional Paper 1348. By Don E. Wilhelms, John F. McCauley, and Newell J. Trask. U.S. Government Printing Office, Washington: 1987. Table 12.2.

References

* * — see Fig. 46 * * * * * * * * * * * *

External links

Cayley at The Moon Wiki
(now defunct) * - includes a couple of craters such as Cayley * {{Craters on the Moon: C-F Impact craters on the Moon