 Lunar Orbiter 4 image | |
| Coordinates | 19°48′S69°06′W / 19.8°S 69.1°W Coordinates: 19°48′S69°06′W / 19.8°S 69.1°W |
|---|---|
| Diameter | 120 km |
| Depth | Unknown |
| Colongitude | 70° at sunrise |
| Eponym | Charles R. Darwin |
Darwin is a lunar impact crater of the type categorised as a walled plain. It lies in the southeastern part of the Moon, and is sufficiently close to the limb to appear significantly foreshortened when viewed from the Earth. Attached to its southern rim is Lamarck. To the northeast is the dark-floored crater Crüger.
Lunar craters are impact craters on Earth's Moon. The Moon's surface has many craters, almost all of which were formed by impacts.
An impact crater is an approximately circular depression in the surface of a planet, moon, or other solid body in the Solar System or elsewhere, formed by the hypervelocity impact of a smaller body. In contrast to volcanic craters, which result from explosion or internal collapse, impact craters typically have raised rims and floors that are lower in elevation than the surrounding terrain. Impact craters range from small, simple, bowl-shaped depressions to large, complex, multi-ringed impact basins. Meteor Crater is a well-known example of a small impact crater on Earth.
Earth's Moon is an astronomical body that orbits the planet and acts as its only permanent natural satellite. It is the fifth-largest satellite in the Solar System, and the largest among planetary satellites relative to the size of the planet that it orbits. The Moon is, after Jupiter's satellite Io, the second-densest satellite in the Solar System among those whose densities are known.
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The outer rim of this formation has been significantly disintegrated by the nearby impacts. The southern and northern parts of the rim in particular are all but destroyed. The eastern rim is somewhat worn but intact, and several small craters lie along the southwestern rim. The satellite crater Darwin B, a fairly large formation with a diameter of 56 kilometers, is attached to the outer western rim.
Parts of the interior floor of Darwin have been resurfaced. The southern floor of Darwin is only roughly level, with irregular surface features and several small craters. There is a dune-like set of hills in the northeast part of the floor, which is "decelerated surface-flow ejecta" from the Orientale basin impact that struck the eastern rim. [1] In the western floor is a large, low, somewhat irregular dome, one of the few such features not found on a mare. There is also the remnant of a small crater at the southern end of the floor.
Ejecta are particles ejected from an area. In volcanology, in particular, the term refers to particles including pyroclastic materials (Tephra) that came out of a volcanic explosion and magma eruption volcanic vent, or crater, has traveled through the air or under water, and fell back on the ground surface or on the ocean floor.
Mare Orientale is a lunar mare. It is located on the western border of the near side and far side of the Moon, 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.
A lunar dome is a type of shield volcano that is found on the surface of the Earth's Moon. They are typically formed by highly viscous, possibly silica-rich lava, erupting from localized vents followed by relatively slow cooling. Lunar domes are wide, rounded, circular features with a gentle slope rising in elevation a few hundred meters to the midpoint. They are typically 8–12 km in diameter, but can be up to 20 km across. Some of the domes contain a small craterlet at the peak.
A system of rilles cut across the northern part of the floor, crossing the eastern rim and continuing to the southeast. These rilles are designated the Rimae Darwin, and they stretch for a distance of about 280 kilometers. To the east of Darwin, this system of rilles crosses Rima Sirsalis, a wide rille that follows a line to the northeast.
Rille is typically used to describe any of the long, narrow depressions in the surface of the Moon that resemble channels. The Latin term is rima, plural rimae. Typically a rille can be up to several kilometers wide and hundreds of kilometers in length. However, the term has also been used loosely to describe similar structures on a number of planets in the Solar System, including Mars, Venus, and on a number of moons. All bear a structural resemblance to each other.
