Mare Orientale
.png)
1967 Lunar Orbiter 4 image
|
|
| Coordinates | 19°24′S 92°48′W / 19.4°S 92.8°WCoordinates: 19°24′S 92°48′W / 19.4°S 92.8°W |
|---|---|
| Diameter | 327 km (203 mi) |
| Eponym | Eastern Sea |
Mare Orientale ("eastern sea" in Latin) is a lunar mare. It is located on the western border of the Moon's nearside and is difficult to see from an Earthbound perspective. Images from spacecraft have revealed it to be one of the most striking large scale lunar features, resembling a target ring bullseye.
During the 1960s, rectified images of Mare Orientale by Gerard Kuiper at the Lunar and Planetary Laboratory gave rise to the notion of it being an impact crater. The structure, with the flat plain of the mare in the center, is about 900 kilometres (560 mi) across and was formed by the impact of an asteroid-sized object, possibly 64 km (40 mi) in diameter and travelling at 15 km/s (9.3 mi/s). Compared with most other lunar basins, Mare Orientale is less flooded by mare basalts, so that much of the basin structure is visible. The basalt in the central portion of the Orientale basin is probably less than 1 km (0.62 mi) in thickness which is much less than mare basins on the earth-facing side of the moon. The collision caused ripples in the lunar crust, resulting in the three concentric circular features. The innermost rings of this vast, multi-ringed crater are the inner and outer Montes Rook, and the outermost ring are the Montes Cordillera, 930 km (580 mi) in diameter. Outward from here, ejecta extend some 500 km (310 mi) from the foot of the mountains and form a rough surface with hummocks and with features radially aligned towards the center.
The Apollo program did not sample rocks from Mare Orientale so its precise age is not known. However, it is the Moon's most recent impact basin, probably rather younger than the Imbrium Basin, which is about 3.85 billion years old. The surrounding basin material is of the Lower Imbrian epoch with the mare material being of the Upper Imbrian epoch.
...
Wikipedia