Main (lunar crater)

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Main
Main and Challis craters 4128 h3.jpg
Lunar Orbiter 4 image (Main above center, Challis below center)
Coordinates 80°48′N10°06′E / 80.8°N 10.1°E / 80.8; 10.1 Coordinates: 80°48′N10°06′E / 80.8°N 10.1°E / 80.8; 10.1
Diameter 46 km
Depth 2.8 km
Colongitude 354° at sunrise
Eponym Robert Main

Main is a lunar impact crater that is located near the north pole of the Moon. The southern rim of this formation has merged with the larger crater Challis to the south, and the level interior floor connects the two craters through a narrower gap. To the north-northwest of Main is Gioja.

Lunar craters

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

Impact crater Circular depression on a solid astronomical body formed by a hypervelocity impact of a smaller object

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.

Moon Earths natural satellite

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.

Contents

This formation consists of three overlapping craters that were joined together when the interior floor was resurfaced by lava flows, leaving a generally circular formation with outward bulges to the west and northeast. The same lava has joined the floor of Main with Challis to the south.

Lava Molten rock expelled by a volcano during an eruption

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.

The surviving rim of Main is a low slope that is nearly level with the surrounding terrain at its top. There is a small crater lying across the eastern rim that is roughly bowl-shaped and missing its western rim. The floor of Main is nearly level, and marked by a number of tiny craterlets that lie nearly in a band across the floor from the southwest towards the northeast. There is no central peak within the crater, and no other hills of note.

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 Main.

MainLatitudeLongitudeDiameter
L81.7° N23.2° E14 km
N82.3° N22.0° E11 km

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Gioja (crater) lunar crater

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Desargues (crater) impact crater

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Kugler (crater) lunar crater

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Baldet (lunar crater) impact crater

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Bolyai (crater) lunar crater

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Cannon (crater) lunar 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.

Goldschmidt (crater) impact crater

Goldschmidt is a large lunar impact crater of the variety commonly termed a walled plain. It lies in the northern part of the Moon's near side, and appears oval in shape due to foreshortening. The rim is actually relatively circular, although the western rim is overlain by the prominent crater Anaxagoras. Nearly attached to the southeast rim is Barrow, and the two formations are separated by a rugged rise about 30 kilometers across. Further to the south is Epigenes.

Loewy (crater) lunar crater

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.

Xenophanes (crater) impact crater

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Pascal (crater) lunar crater

Pascal is a lunar impact crater that lies near the northern limb of the Moon, on the western side of the pole. It is located to the north of the eroded crater Desargues, and just east of Brianchon. Pascal can be located by finding the crater Carpenter and then following the surface to the northwest towards the limb. However the visibility of this formation can be affected by libration.

Fermi (crater) impact crater

Fermi is a large lunar impact crater of the category named a walled plain. It was named after Italian-American physicist and Nobel laureate Enrico Fermi. It lies on the far side of the Moon and can not be viewed from the Earth. Thus this feature must be viewed from an orbiting spacecraft.

Challis (crater) lunar crater

Challis is a lunar impact crater that is located in the northern regions of the Moon's near side, close enough to the limb to appear significantly foreshortened when viewed from the Earth. It is joined to the crater Main through a break in the northern rim, and is close to Scoresby along the southeast side.

Crocco (crater) impact crater

Crocco is a lunar impact crater that is located on the far side of the Moon from the Earth. It is located to the northeast of the huge walled plain Planck, and northwest of the equally huge Poincaré. Just to the north, within one crater diameter, is the crater Koch.

Chevallier (crater) impact crater

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.

Mason (crater) impact crater

Mason is the remains of a lunar impact crater that lies in the northeastern part of the Moon. It is nearly attached to the eastern rim of the flooded crater Plana, and southeast of Bürg. Along the northern rim of Mason is the southern edge of the Lacus Mortis, a small lunar mare. To the south is the larger Lacus Somniorum.

Schumacher (crater) impact crater

Schumacher is a lunar impact crater that lies in the northeast part of the Moon, just to the north of the larger walled plain Messala. The two formations are separated by a rough strip of terrain less than 10 kilometers across, and bisected by a pair of small, co-joined craters. The northern member of this pair lies across the southern rim of Schumacher, and intrudes into the interior floor.

References

Ewen Whitaker British astronomer

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.

NASA space-related agency of the United States government

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.

United States Geological Survey Scientific agency of the United States government

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.