D'Alembert (crater)
Encyclopedia
D'Alembert is a large lunar
impact crater
located in the northern hemisphere
on the far side of the Moon
, to the northeast of the somewhat smaller walled plain Campbell
. Astride the southwest rim of D'Alembert is Slipher
. To the north is the crater Yamamoto
, and to the south-southwest lies Langevin
. This walled plain has the same diameter as Clavius
on the near side, making it one of the largest such formations on the Moon.
As with many lunar walled plains of comparable dimensions, the outer rim of this formation has been worn and battered by subsequent impacts. Besides Slipher, the most notable of these craters is D'Alembert Z intruding into the northern rim. There is also a small crater on the northwest inner wall that has a wide cleft in its eastern side, and a smaller crater along the southeastern inner wall. As eroded as the rim may be, its form can still be readily discerned as a roughly circular ridge line in the lunar terrain.
The interior floor of D'Alembert is a relatively level surface, at least in comparison with the rough terrain that surrounds the crater rim. It is marked with a number of small crater impacts, the largest being D'Alembert G and D'Alembert E toward the eastern rim. In the southwest, the floor is more irregular due to the outer rampart and layers of ejecta from Slipher. A pair of shallow clefts in the floor surface radiate away from this crater, beginning near the mid-point of D'Alembert and reaching half-way toward the inner wall.
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
impact crater
Impact crater
In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...
located in the northern hemisphere
Northern Hemisphere
The Northern Hemisphere is the half of a planet that is north of its equator—the word hemisphere literally means “half sphere”. It is also that half of the celestial sphere north of the celestial equator...
on the far side of the Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
, to the northeast of the somewhat smaller walled plain Campbell
Campbell (lunar crater)
Campbell is a large lunar crater that is located in the northern hemisphere on the far side of the Moon. It lies to the southwest of the walled plain D'Alembert, an even larger formation. If Campbell were located on the near side of the Moon as seen from the Earth, it would form one of the largest...
. Astride the southwest rim of D'Alembert is Slipher
Slipher (lunar crater)
Slipher is a lunar impact crater that is located in the northern latitudes on the far side of the Moon. The crater overlies the southwestern outer rim of the much larger walled plain D'Alembert, and it occupies a portion of the interior floor of D'Alembert...
. To the north is the crater Yamamoto
Yamamoto (crater)
Yamamoto is a damaged lunar crater that is located to the north of the large walled plain D'Alembert. To the north-northeast is the crater Avogadro. This feature lies on the northern hemisphere of the Moon's far side....
, and to the south-southwest lies Langevin
Langevin (crater)
Langevin is a crater on the far side of the Moon. It is located to the east of the walled plain Campbell, and to the west of the crater Chandler....
. This walled plain has the same diameter as Clavius
Clavius (crater)
Clavius is one of the largest crater formations on the Moon, and it is the third largest crater on the visible near side. It is located in the rugged southern highlands of the Moon, to the south of the prominent ray crater Tycho.- Description :...
on the near side, making it one of the largest such formations on the Moon.
As with many lunar walled plains of comparable dimensions, the outer rim of this formation has been worn and battered by subsequent impacts. Besides Slipher, the most notable of these craters is D'Alembert Z intruding into the northern rim. There is also a small crater on the northwest inner wall that has a wide cleft in its eastern side, and a smaller crater along the southeastern inner wall. As eroded as the rim may be, its form can still be readily discerned as a roughly circular ridge line in the lunar terrain.
The interior floor of D'Alembert is a relatively level surface, at least in comparison with the rough terrain that surrounds the crater rim. It is marked with a number of small crater impacts, the largest being D'Alembert G and D'Alembert E toward the eastern rim. In the southwest, the floor is more irregular due to the outer rampart and layers of ejecta from Slipher. A pair of shallow clefts in the floor surface radiate away from this crater, beginning near the mid-point of D'Alembert and reaching half-way toward the inner wall.
Satellite craters
By convention these features are identified on lunar maps by placing the letter on the side of the crater mid-point that is closest to D'Alembert.| D'Alembert | Latitude | Longitude | Diameter |
|---|---|---|---|
| E | 52.8° N | 168.2° E | 22 km |
| G | 50.9° N | 167.5° E | 18 km |
| J | 47.5° N | 170.4° E | 20 km |
| Z | 55.4° N | 165.6° E | 44 km |