Drygalski (crater)
Encyclopedia
Drygalski is a large lunar
impact crater
that lies along the southern limb of the Moon
. It partly overlies the crater Ashbrook
to the west on the far side of the Moon
. Just to the north of Drygalski is the smaller Boltzmann
. The location of this crater restricts its observation from the Earth
, and even under conditions of favorable libration
it is viewed from the edge. It is only illuminated by the Sun at an oblique angle, and it lies close to the south polar craters that are permanently shielded from sunlight.
The outer rim of this crater has been worn and eroded by subsequent impacts, leaving a rugged, mountainous ring that is overlaid in places by small craters. The most notable of these are Drygalski P across the southwest rim where it joins Ashbrook, and Drygalski V along the north-northwest inner wall. There is a small catena, or crater chain, beginning tangentially the northern outer rim then arcing to the north towards Boltzmann. To the south is an odd formation of two or more small craters, forming a short valley.
Portions of the interior floor within the inner walls is flat and level, having been resurfaced by lava
. The flattest parts are in the southern and eastern sections of the interior. The surface is more rugged in the west, and is marked by several small craterlets. At the mid-point of the interior is a rugged central peak formation with several smaller ridges along the flanks.
The following craters have been renamed by the IAU
.
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...
that lies along the southern limb 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...
. It partly overlies the crater Ashbrook
Ashbrook (crater)
Ashbrook is a large lunar impact crater that is located in the vicinity of the south pole on the far side of the Moon, and so cannot be viewed directly from the Earth. The eastern face of the crater has been overlain by the similar-sized Drygalski, and more than half the interior floor of Ashbrook...
to the west 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...
. Just to the north of Drygalski is the smaller Boltzmann
Boltzmann (crater)
Boltzmann is an old lunar crater that is located along the southern limb of the Moon, in the vicinity of the south pole. At this location the crater is viewed from the side from Earth, and so not much detail can be seen...
. The location of this crater restricts its observation from the Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
, and even under conditions of favorable libration
Libration
In astronomy, libration is an oscillating motion of orbiting bodies relative to each other, notably including the motion of the Moon relative to Earth, or of Trojan asteroids relative to planets.-Lunar libration:...
it is viewed from the edge. It is only illuminated by the Sun at an oblique angle, and it lies close to the south polar craters that are permanently shielded from sunlight.
The outer rim of this crater has been worn and eroded by subsequent impacts, leaving a rugged, mountainous ring that is overlaid in places by small craters. The most notable of these are Drygalski P across the southwest rim where it joins Ashbrook, and Drygalski V along the north-northwest inner wall. There is a small catena, or crater chain, beginning tangentially the northern outer rim then arcing to the north towards Boltzmann. To the south is an odd formation of two or more small craters, forming a short valley.
Portions of the interior floor within the inner walls is flat and level, having been resurfaced by lava
Lava
Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...
. The flattest parts are in the southern and eastern sections of the interior. The surface is more rugged in the west, and is marked by several small craterlets. At the mid-point of the interior is a rugged central peak formation with several smaller ridges along the flanks.
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 Drygalski.| Drygalski | Latitude | Longitude | Diameter |
|---|---|---|---|
| P | 81.0° S | 99.9° W | 30 km |
| V | 78.5° S | 93.4° W | 21 km |
The following craters have been renamed by the IAU
International Astronomical Union
The International Astronomical Union IAU is a collection of professional astronomers, at the Ph.D. level and beyond, active in professional research and education in astronomy...
.
- Drygalski Q — See AshbrookAshbrook (crater)Ashbrook is a large lunar impact crater that is located in the vicinity of the south pole on the far side of the Moon, and so cannot be viewed directly from the Earth. The eastern face of the crater has been overlain by the similar-sized Drygalski, and more than half the interior floor of Ashbrook...
.