Fermi (crater)

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Fermi crater 3121 med.jpg
Coordinates 19°18′S 122°36′E / 19.3°S 122.6°E / -19.3; 122.6Coordinates: 19°18′S 122°36′E / 19.3°S 122.6°E / -19.3; 122.6
Diameter 183 km
Depth Unknown
Colongitude 240° at sunrise
Eponym Enrico Fermi
Apollo 17 mapping camera image of the interior
Oblique Apollo 17 image, facing east

Fermi is a large lunar crater of the category named a walled plain. 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.

The most notable aspect of Fermi is that the large and prominent crater Tsiolkovskiy intrudes into its southeastern rim. Unlike Tsiolkovskiy, however, the interior of Fermi is not covered by dark basaltic lava, and so it is barely distinguishable from the surrounding rugged and battered terrain. If it were located on the near side of the Moon, however, this would be one of the largest visible craters, with a dimension roughly equal to the crater Humboldt, lying several hundred kilometers to the west-southwest.

This formation has been significantly eroded and damaged by subsequent impacts, and several notable craters lie across the rim and within the basin. Delporte is the most notable of these, lying across the northwest rim. Just to the east and inside the northern rim of Fermi is Litke. The smaller crater Xenophon is centered across the southern rim. In the southern half of the floor are the craters Diderot and Babakin.

The rim, where it survives, is the most intact along the northern half. The southern half of the rim has been nearly obliterated, forming an irregular stretch of ground. The interior floor of Fermi has been modified by the creation of Tsiolkovskiy, with striations in the northeastern floor of Fermi, and parallel ridges along the western rim of Tsiolkovskiy. The remaining sections of the floor is somewhat more level, although pock-marked by myriads of tiny craterlets. The central section of the floor in particular has several clustered crater formations.

Prior to formal naming in 1970 by the IAU,[1] the crater was known as Basin V.[2]


  1. ^ Fermi, Gazetteer of Planetary Nomenclature, International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN)
  2. ^ Lunar Farside Chart (LFC-1A)

External links[edit]

The following are L&PI topographic maps that show portions of Fermi.