left, 240px, Location of the crater Democritus
Democritus is a
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 on the northern part of the
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 ...
, just to the north 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 j ...
. Just to the south of Democritus is the
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 ...
-flooded crater
Gärtner, which forms a bay on the
mare
A mare is an adult female horse or other equine. In most cases, a mare is a female horse over the age of three, and a filly is a female horse three and younger. In Thoroughbred horse racing, a mare is defined as a female horse more than fo ...
. Directly to the north is
Arnold, another flooded formation.
Description
The rim of Democritus is generally sharp-edged and shows little sign of erosion. It forms not quite a circle, with outward notch-like bulges that give it a slightly irregular shape. The inner walls have single or double
terrace
Terrace may refer to:
Landforms and construction
* Fluvial terrace, a natural, flat surface that borders and lies above the floodplain of a stream or river
* Terrace, a street suffix
* Terrace, the portion of a lot between the public sidewalk an ...
s that lead down to a relatively flat interior floor. Near the midpoint of the crater is a small central peak.
Names
Democritus is named after
the Greek philosopher of the same name. Like many of the craters on the Moon's near side, it was given its name by
Giovanni Riccioli
Giovanni Battista Riccioli, SJ (17 April 1598 – 25 June 1671) was an Italian astronomer and a Catholic priest in the Jesuit order. He is known, among other things, for his experiments with pendulums and with falling bodies, for his discussion ...
, whose 1651 nomenclature system has become standardized. Earlier lunar cartographers had given the feature different names:
Michael van Langren's 1645 map calls it "Alfonsi IX Reg. Cast." after
Alfonso IX of León and Castile, and
Johannes Hevelius
Johannes Hevelius
Some sources refer to Hevelius as Polish:
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Some sources refer to Hevelius as German:
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*of the Royal Society
* (in German also known as ''Hevel''; pl, Jan Heweliusz; – 28 January 1687) was a councillor ...
called it "Mons Bontas".
[Ewen A. Whitaker, ''Mapping and Naming the Moon'' (Cambridge University Press, 1999), p. 202.]
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 Democritus.
References
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Impact craters on the Moon
{{Craters on the Moon: C-F
