Lassell is a small 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 is located in the eastern part of the

Mare Nubium Mare Nubium (Latin ''nūbium'', the "sea of clouds") is a lunar mare in the Nubium basin on the Moon's near side. The mare is located just to the southeast of Oceanus Procellarum. Formation The basin containing Mare Nubium is believed to ha ...

. It was named after British astronomer

William Lassell William Lassell (18 June 1799 – 5 October 1880) was an English merchant and astronomer.Alpetragius and southwest of Alphonsus. Lassel crater AS16-P-5401

Description

The interior of Lassell has been flooded and resurfaced by

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 ...

, leaving a nearly flat surface with a low remaining outer rim. The surface has a low

albedo Albedo (; ) is the measure of the diffuse reflection of solar radiation out of the total solar radiation and measured on a scale from 0, corresponding to a black body that absorbs all incident radiation, to 1, corresponding to a body that refl ...

, giving the interior a dark appearance. The surviving outer wall is generally circular but with a somewhat

polygon In geometry, a polygon () is a plane figure that is described by a finite number of straight line segments connected to form a closed ''polygonal chain'' (or ''polygonal circuit''). The bounded plane region, the bounding circuit, or the two to ...

al shape. To the east-northeast is a circular, bowl-shaped crater designated Lassell B. This formation has a higher albedo than its surroundings and so appears relatively bright, especially at high sun angles. The tiny crater Lassell D is located to the west-northwest of Lassell, about halfway to the ruined crater Guericke. This craterlet is surrounded by a patch of high-

surface, and is an example of a prominent lunar bright patch. The light hue is thought to be an indication of recent formation, at least in lunar geological terms.

Lassell massif

To the west of Lassell, at coordinates 14.65°S, 350.96°E is a small highland area called the Lassell Massif, which has a reddish color relative to the surrounding mare. The massif was created by series of eruptions of viscous silicic lavas starting 4.07 billion years ago. Its surface is suspected to be partially buried by ejecta from Copernicus crater. The southern domes Lassell G and Lassell K have most silica-rich composition and feature a caldera-like depressions on tops.The Lassell massif—A silicic lunar volcano
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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 Lassell.

References

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External links

Lassell at The Moon Wiki
* * {{cite web, last = Wood , first = Chuck , date = January 31, 2010 , url = http://lpod.wikispaces.com/January+31%2C+2010 , title = Spotted Moon, publisher = Lunar Photo of the Day Impact craters on the Moon