Gum (crater)

Gum
	Lunar Orbiter 4 image showing the eastern 2/3 of Gum
Coordinates	40°24′S88°36′E / 40.4°S 88.6°E Coordinates: 40°24′S88°36′E / 40.4°S 88.6°E
Diameter	55 km
Depth	Unknown
Colongitude	272° at sunrise
Eponym	Colin S. Gum

Last updated August 09, 2019

Gum is a lunar impact crater that is located near the southeastern limb of the Moon, and is viewed nearly from the side from Earth. It lies along the western edge of the irregular Mare Australe, to the northeast of the crater Hamilton. To the north-northwest is the larger Abel, and to the east-southeast on the far side of the Moon is Jenner.

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.

The interior floor of this crater has been completely resurfaced by lava that has entered through a break in the eastern rim. The surviving rim forms a shallow, arcing ridge about the interior. A small flooded crater lies across the southeast rim, and the remains of a small crater form an incision along the northeastern rim. The interior floor has the same low albedo as the lunar mare to the east, and is marked only by a few small craterlets.

Lava is molten rock generated by geothermal energy and expelled through fractures in planetary crust or in an eruption, usually at temperatures from 700 to 1,200 °C. The structures resulting from subsequent solidification and cooling are also sometimes described as lava. The molten rock is formed in the interior of some planets, including Earth, and some of their satellites, though such material located below the crust is referred to by other terms.

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.

The lunar maria are large, dark, basaltic plains on Earth's Moon, formed by ancient volcanic eruptions. They were dubbed maria, Latin for "seas", by early astronomers who mistook them for actual seas. They are less reflective than the "highlands" as a result of their iron-rich composition, and hence appear dark to the naked eye. The maria cover about 16% of the lunar surface, mostly on the side visible from Earth. The few maria on the far side are much smaller, residing mostly in very large craters. The traditional nomenclature for the Moon also includes one oceanus (ocean), as well as features with the names lacus (lake), palus (marsh), and sinus (bay). The last three are smaller than maria, but have the same nature and characteristics.

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 Gum.

Gum	Latitude	Longitude	Diameter
S	39.8° S	85.0° E	33 km

Related Research Articles

Agatharchides is a lunar impact crater located at the southern edge of Oceanus Procellarum, in the region between the Mare Humorum and Mare Nubium. To the east-southeast is the crater Bullialdus, and to the south-southwest lies Loewy. It is named after the Greek geographer Agatharchides.

Archytas is a lunar impact crater that protrudes into the northern edge of Mare Frigoris. To the northwest is the comparably sized crater Timaeus, and the smaller Protagoras lies in the opposite direction to the southeast. Further to the southwest, beyond the opposite edge of the mare, is the dark-floored crater Plato.

Boss is a lunar impact crater that is located along the northeast rim of the Moon's near side. Due to its location, the crater is viewed from the side by observers on the Earth, and its visibility is subject to libration effects.

Bel'kovich is a large lunar impact crater of the form termed a walled plain. The formation has been heavily eroded by a history of subsequent impacts, leaving it reshaped, worn, and the features softened and rounded. Bel'kovich is located along the northeastern limb of the Moon, and so its visibility is subject to libration effects. From the Earth this crater is viewed from the side, making it difficult to view it in detail.

De La Rue is the remnant of a lunar impact crater, or possibly several merged craters, creating a formation sometimes called a walled plain. It lies in the northeastern part of the Moon on the near side, and so appears foreshortened due to its location. This formation lies to the north-northwest of the prominent crater Endymion, just beyond the eastern extreme of Mare Frigoris. The crater Strabo intrudes into the northern part of De La Rue's northern rim, and the smaller Thales is attached to the northwestern part of the wall.

Blackett is a lunar impact crater that lies on the far side of the Moon, behind the southwest limb. It lies beyond the southeast outer ring of the immense Mare Orientale basin. The formation of that major feature has left Blackett deeply marked with ridge features trending from the northwest. Much of the crater has been shaped by the ejecta from Mare Orientale, particularly along the western half of the crater.

Cannon is a lunar impact crater that is located near the east-northeastern limb of the Moon's near side. It lies just to the northwest of the Mare Marginis, and south-southeast of the crater Plutarch. Farther to the east-northeast is Hubble.

Carmichael is a lunar impact crater that is located along the eastern edge of the Sinus Amoris, in the northeastern quadrant of the Moon's near side. Its diameter is 20 km. It was named after American psychologist Leonard Carmichael. It lies within a couple of crater diameters south-southwest of the smaller crater Hill. Further to the east-northeast is the prominent crater Macrobius. Carmichael was designated Macrobius A before being given its current name by the IAU.

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.

Loewy is a small lunar impact crater that lies along the eastern rim of Mare Humorum, in the southwest part of the Moon's near side. It was named after French astronomer Maurice Loewy. This is a lava-flooded formation that lies to the southwest of the larger, lava-flooded crater Agatharchides. To the southeast is an even larger lava-flooded formation, Hippalus.

Damoiseau is a lunar impact crater that is located just to the west of the Oceanus Procellarum, in the western part of the Moon's near side. It lies due east of the prominent crater Grimaldi, a walled plain with a distinctive dark floor. Due south of Damoiseau is the crater Sirsalis.

Cook is a lunar impact crater that lies in the western part of the Mare Fecunditatis, just to the southeast of the prominent crater Colombo. To the southwest is Monge.

Crozier is a lunar impact crater that is located on the southwest edge of Mare Fecunditatis, a lunar mare in the eastern part of the Moon's near side. It lies to the east-northeast of the prominent crater Colombo, and southeast of the small crater Bellot.

Carnot is a large crater in the northern part of the Moon's far side. It intrudes into the southern rim of the huge walled plain Birkhoff. To the west-southwest of Carnot is the crater Paraskevopoulos.

Chevallier is a lunar impact crater that is located in the northeastern part of the Moon's near side, about a crater diameter east-southeast of the prominent crater Atlas. To the south-southeast of Chevallier is the flooded crater Shuckburgh.

Charlier is a lunar impact crater that is located on the far side of the Moon. To the south-southeast is the larger crater Kovalevskaya, and northeast of Charlier is Perrine.

Palmieri is a lunar impact crater that lies to the southwest of the Mare Humorum, in the southwestern quadrant of the Moon's near side. It lies due south of the crater Liebig and east-northeast of the larger Fourier.

Fourier is a lunar impact crater that is located in the southwestern part of the Moon's near side, just to the southeast of the crater Vieta. To the northeast is the Mare Humorum. The rim of this crater is roughly circular, but appears oval when viewed from the Earth due to foreshortening.

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.

Kurchatov is a lunar impact crater that is located on the Moon's far side. It is just to the southwest of the crater Wiener, and farther to the southeast of Bridgman. A couple of crater diameters to the south of Kurchatov is the northern edge of the Mare Moscoviense.

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 4 image showing the eastern 2/3 of Gum
Coordinates	40°24′S88°36′E / 40.4°S 88.6°E / -40.4; 88.6 Coordinates: 40°24′S88°36′E / 40.4°S 88.6°E / -40.4; 88.6
Diameter	55 km
Depth	Unknown
Colongitude	272° at sunrise
Eponym	Colin S. Gum