Galois (crater)

Galois
	Lunar Orbiter 1 image
Coordinates	14°12′S151°54′W / 14.2°S 151.9°W Coordinates: 14°12′S151°54′W / 14.2°S 151.9°W
Diameter	222 km
Depth	Unknown
Colongitude	156° at sunrise
Eponym	Évariste Galois

Last updated August 07, 2019

Galois is a large lunar impact crater on the far side of the Moon. Features of this class are commonly termed walled plains, due to their appearance and dimension. It is located just to the southeast of another huge walled plain, Korolev, a formation nearly double the diameter of Galois. Several hundred kilometers due south is another enormous feature, Apollo.

Lunar craters are impact craters on Earth's Moon. The Moon's surface has many craters, almost all of which were formed by impacts.

An impact crater is an approximately circular depression in the surface of a planet, moon, or other solid body in the Solar System or elsewhere, formed by the hypervelocity impact of a smaller body. In contrast to volcanic craters, which result from explosion or internal collapse, impact craters typically have raised rims and floors that are lower in elevation than the surrounding terrain. Impact craters range from small, simple, bowl-shaped depressions to large, complex, multi-ringed impact basins. Meteor Crater is a well-known example of a small impact crater on Earth.

Earth's Moon is an astronomical body that orbits the planet and acts as its only permanent natural satellite. It is the fifth-largest satellite in the Solar System, and the largest among planetary satellites relative to the size of the planet that it orbits. The Moon is, after Jupiter's satellite Io, the second-densest satellite in the Solar System among those whose densities are known.

This is a heavily eroded feature with a rim that has been reshaped by impacts, particularly along the northwest edge where it lies near Korolev. An influx of material forms an inward bulge along the southern edge, which is impacted by Galois Q. The interior floor is also overlain by several notable craters, with the craters Galois A and Galois L forming a nearly matching pair near the midpoint. Along the northeastern rim are Galois B and Galois C, while Galois U lies against the northwestern inner wall. The most intact and nearly level section of floor is along the southwestern part of the interior.

A small, unnamed impact crater located along the northeastern rim of Galois has a relatively high albedo and lies at the focus of a small ray system. The rays from this impact are the most prominent to the north, where they cross the floor of the crater Mechnikov. Craters that have a ray system are considered indicative of a relatively recent impact, as the rays are steadily erased by space weathering.

Albedo is the measure of the diffuse reflection of solar radiation out of the total solar radiation received by an astronomical body. It is dimensionless and measured on a scale from 0 to 1.

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 several times the diameter of their originating crater, and are often accompanied by small secondary craters formed by larger chunks of ejecta. Ray systems have been identified on the Moon, Earth, Mercury, and some moons of the outer planets. Originally it was thought that they existed only on planets or moons lacking an atmosphere, but more recently they have been identified on Mars in infrared images taken from orbit by 2001 Mars Odyssey's thermal imager.

Mechnikov is an impact crater on the far side of the Moon. It is located just to the northeast of the much larger walled plain Galois, being separated by a stretch of irregular terrain about 20–30 km in width.

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 Galois.

Galois	Latitude	Longitude	Diameter
A	14.0° S	152.5° W	54 km
B	11.3° S	151.8° W	20 km
C	12.4° S	150.5° W	22 km
F	13.9° S	146.4° W	13 km
H	15.2° S	150.9° W	19 km
L	15.5° S	152.0° W	51 km
M	16.1° S	152.4° W	18 km
Q	15.2° S	154.7° W	132 km
S	14.5° S	154.9° W	18 km
U	13.2° S	154.7° W	35 km

Oblique view of Galois A

Related Research Articles

Doppler is a lunar impact crater named for Christian Doppler that is located at the southern edge of the walled plain Korolev, on the far side of the Moon. To the east are the craters Das and Galois. Farther to the southwest of Doppler is Mohorovičić.

Korolev is a large lunar impact crater of the walled plain or basin type, named for Soviet rocket engineer Sergei Korolev. It lies on the far side of the Moon, and the northern part of its floor crosses the lunar equator. Notable nearby craters include Galois just to the southeast, Das to the south-southeast, Doppler attached to the southern rim, and Kibal'chich to the northeast. Rays of the crater Crookes cover parts of the basin.

Fabry is a large lunar impact crater of the form termed a walled plain. It is located on the far side of the Moon, just beyond the northeastern limb. Parts of this area are sometimes brought into view by the effects of libration, but the terrain is seen from the edge and so not much in the way of detail can be observed.

Brisbane is a lunar impact crater that is located in the southeastern part of the Moon, to the south of the crater Peirescius. To the northwest lie the craters Vega and Reimarus, and farther to the east is the walled plain Lyot. Due to its proximity to the limb, foreshortening of this crater causes it to appear somewhat elliptical in shape, even though it is actually circular.

Buffon is a lunar impact crater that is located on the southern hemisphere on the far side of the Moon. It lies a crater diameter south of the large walled plain Chebyshev. To the northeast is the crater Langmuir and to the southwest is Leavitt. Buffon lies nearly at the midpoint between these formations.

Casatus is a lunar impact crater that is located near the southern limb of the Moon. The north-northeast rim of the crater overlies a portion of the slightly larger crater Klaproth. Along the western rim, Casatus A intrudes somewhat into the interior, producing an inward-bowing rim. To the southeast of Casatus is Newton.

Demonax is a lunar impact crater near the southern limb of the Moon. This location makes the crater difficult to observe due to foreshortening. The crater is also illuminated at a very low angle, when it is in the sunlit side. Demonax lies just to the north of the crater Scott, one of the south polar formations. To the north-northwest is Boguslawsky.

Chebyshev is a large lunar impact crater that lies in the southern hemisphere on the far side of the Moon. The somewhat smaller crater Langmuir is intruding into the east-southeastern rim of Chebyshev, forming a chain of large craters with Brouwer on Langmuir's eastern rim.

Pasteur is a large lunar impact crater, approximately 233 kilometers in diameter, belonging to the category termed a walled plain. It was named after French chemist and microbiologist Louis Pasteur. It lies on the far side of the Moon as seen from the Earth, just beyond the eastern limb. The vicinity of this crater is occasionally brought into view from Earth due to librations, although not much detail can be seen.

Crookes is a lunar impact crater that lies on the Moon's far side as seen from the Earth. It lies just to the southwest of the giant crater Korolev. To the southwest of Crookes is McKellar.

Dyson is a lunar impact crater, 63 kilometers in diameter, that lies on the far side of the Moon, past the northwest limb. It is located in the northern part of the surface, to the northwest of the crater Coulomb, and east of van't Hoff.

Chandler is a lunar impact crater in the northern hemisphere, on the Moon's far side. It lies to the southeast of the large walled plain D'Alembert, and southeast of the slightly smaller Chernyshev crater.

Congreve is a lunar impact crater that is located on the far side of the Moon relative to the Earth, and lies across the lunar equator. It lies to the west-northwest of the massive walled plain Korolev. To the southeast is the crater Icarus, and due north is Zhukovskiy.

Gauricus is a lunar impact crater that is located in the rugged southern part of the Moon's near side. It was named after Italian astronomer Luca Gaurico. Nearly attached to the western rim is the heavily eroded crater Wurzelbauer, and to the north-northwest lies Pitatus.

Montanari is a lunar impact crater. It is located to the west-southwest of the prominent ray crater Tycho, and is attached to the southern rim of the walled plain Wilhelm. Along the northwestern side is the crater remnant Lagalla, and just to the south is the large walled plain Longomontanus.

Fraunhofer is a lunar impact crater that is located just to the south-southwest of the walled plain Furnerius, in the southeastern part of the Moon. This crater appears foreshortened when viewed from the Earth, and is actually nearly circular.

Fersman is a large lunar impact crater on the Moon's far side. It lies to the east of the crater Poynting, and west-northwest of Weyl. To the south is the huge walled plain Hertzsprung.

Icarus is a lunar impact crater that lies on the Moon's far side. It is located to the west of the huge walled plain Korolev, and less than two crater diameters to the east of the crater Daedalus. To the south of Icarus is the smaller Amici.

Wood is a lunar impact crater that lies entirely within the interior of the much larger walled plain Landau, on the far side of Moon. Wood is situated along the northwestern part of the floor of Landau, and shares a common northwestern rim with the larger impact. The inner wall of the northwest rim extends inward about halfway toward the crater midpoint, where there is a central peak. The rim of Wood is somewhat worn and uneven, with a small crater laid across the southwest section. The surviving interior floor is nearly level and is marked only by a few tiny craterlets.

References

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Ewen Adair Whitaker was a British-born astronomer who specialized in lunar studies. During World War II he was engaged in quality control for the lead sheathing of hollow cables strung under the English Channel as part of the "Pipe Line Under The Ocean" Project (PLUTO) to supply gasoline to Allied military vehicles in France. After the war, he obtained a position at the Royal Greenwich Observatory working on the UV spectra of stars, but became interested in lunar studies. As a sideline, Whitaker drew and published the first accurate chart of the South Polar area of the Moon in 1954, and served as director of the Lunar Section of the British Astronomical Association.

The National Aeronautics and Space Administration is an independent agency of the United States Federal Government responsible for the civilian space program, as well as aeronautics and aerospace research.

The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology, geography, geology, and hydrology. The USGS is a fact-finding research organization with no regulatory responsibility.

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Lunar Orbiter 1 image
Coordinates	14°12′S151°54′W / 14.2°S 151.9°W / -14.2; -151.9 Coordinates: 14°12′S151°54′W / 14.2°S 151.9°W / -14.2; -151.9
Diameter	222 km
Depth	Unknown
Colongitude	156° at sunrise
Eponym	Évariste Galois