Arnold is a
lunar
Lunar most commonly means "of or relating to the Moon".
Lunar may also refer to:
Arts and entertainment
* ''Lunar'' (series), a series of video games
* "Lunar" (song), by David Guetta
* "Lunar", a song by Priestess from the 2009 album ''Prior t ...
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 craters ...
that is located in the north-northeastern part of the visible
Moon
The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...
, near the lunar limb. This location gives the crater a notably oval appearance due to foreshortening, although the formation is actually relatively round. It lies to the northeast of the
Mare Frigoris
Mare Frigoris (Latin ''frīgōris'', the "Sea of Cold") is a lunar mare in the far north of the Moon. It is located in the outer rings of the Procellarum basin, just north of Mare Imbrium, and stretches east to north of Mare Serenitatis. It is ju ...
, to the north of the crater
Democritus
Democritus (; el, Δημόκριτος, ''Dēmókritos'', meaning "chosen of the people"; – ) was an Ancient Greek pre-Socratic philosopher from Abdera, primarily remembered today for his formulation of an atomic theory of the universe. No ...
. West of Arnold is the smaller crater
Moigno.
The ancient rim of Arnold has been worn and rounded by ages of subsequent bombardment. There is a gap in the wall to the southwest, marked by the tiny crater Arnold J, and the wall is relatively low along the eastern edge. The northern half of the rim is the most intact, particularly to the northeast where is joins the satellite crater Arnold A.
The inner floor of Arnold crater has been 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 ...
, and is relatively flat except for a number of tiny craterlets. The most notable crater in the interior is Arnold F, in the northwest section. If the crater once possessed a central peak, no sign of this feature now remains.
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 Arnold.
References
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External links
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{{Authority control
Impact craters on the Moon