Editing D'Alembert (crater)

{{short description|Lunar impact crater}}
{{DISPLAYTITLE:d'Alembert (crater)}}
{{Infobox Lunar crater
| image       = Normal d-alembert-clem.jpg
| caption     = [[Clementine (spacecraft)|Clementine]] mosaic
| coordinates = {{coord|50.8|N|163.9|E|globe:moon_type:landmark|display=inline,title}}
| diameter    = 248 km
| depth       = ''Unknown''
| colong      = 201
| eponym      = [[Jean le Rond d'Alembert|Jean d'Alembert]]
}}
[[Image:D'Alembert crater 5053 med.jpg|thumb|right|240px|Oblique [[Lunar Orbiter 5]] image, facing west]]
'''d'Alembert''' is a large [[Lunar craters|lunar]] [[impact crater]] located in the [[northern hemisphere]] on the [[Far side (Moon)|far side]] of the [[Moon]], to the northeast of the somewhat smaller walled plain [[Campbell (lunar crater)|Campbell]]. Astride the southwest rim of d'Alembert is [[Slipher (lunar crater)|Slipher]]. To the north is the crater [[Yamamoto (crater)|Yamamoto]], and to the south-southwest lies [[Langevin (crater)|Langevin]]. This walled plain has the same diameter as [[Clavius (crater)|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 [[wikt:rampart|rampart]] and layers of ejecta from Slipher. A pair of shallow clefts in the floor surface radiate away from this crater, beginning near the midpoint 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 midpoint that is closest to D'Alembert.

{| class="wikitable"
!width="25%" style="background:#eeeeee;" |D'Alembert 
!width="25%" style="background:#eeeeee;" |Latitude
!width="25%" style="background:#eeeeee;" |Longitude
!width="25%" style="background:#eeeeee;" |Diameter
|-
|align="center"|E
|align="center"|52.8° N
|align="center"|168.2° E
|align="center"|22&nbsp;km
|-
|align="center"|G
|align="center"|50.9° N
|align="center"|167.5° E
|align="center"|18&nbsp;km
|-
|align="center"|J
|align="center"|47.5° N
|align="center"|170.4° E
|align="center"|20&nbsp;km
|-
|align="center"|Z
|align="center"|55.4° N
|align="center"|165.6° E
|align="center"|44&nbsp;km
|}

D'Alembert G is characterised by an extremely high [[rockfall]] density by lunar standards.<ref>{{cite journal |date=2020-06-08 |first=Valentin Tertius |last=Bickel |display-authors=etal |title=Impacts drive lunar rockfalls over billions of years |pages=1-7 |url=https://www.researchgate.net/publication/342008792 |doi=10.1038/s41467-020-16653-3 |journal=Nature Communications |eissn=2041-1723 |volume=11|pmc=7280507 }}</ref>{{rp|2}}

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{{refend}}

[[Category:Impact craters on the Moon]]
{{Craters on the Moon: C-F}}