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Gassendi (crater)
Encyclopedia
Gassendi is a large lunar
crater
feature located at the northern edge of Mare Humorum
. The formation has been inundated by lava
during the formation of the mare
, so only the rim and the multiple central peaks remain above the surface. The outer rim is worn and eroded, although it retains a generally circular form. A smaller crater Gassendi A intrudes into the northern rim, and joins a rough uplift at the northwest part of the floor. The crater pair bears a curious resemblance to a diamond ring.
In the southern part of the crater floor is a semi-circular ridge-like formation that is concentric with the outer rim. It is in the southern part where the rim dips down to its lowest portion, and a gap appears at the most southern point. The rim varies in height from as little as 200 meters to as high as 2.5 kilometers above the surface. The floor has numerous hummocks and rough spots. There is also a system of rille
s that criss-cross the floor, named the Rimae Gassendi.
On some older maps the crater Gassendi A was called Clarkson, after the British amateur astronomer and selenographer Roland L T Clarkson, but this name is not officially recognized by the IAU
and the name has been removed.
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...
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...
feature located at the northern edge of Mare Humorum
Mare Humorum
Mare Humorum is a lunar mare. The impact basin it is located in is 825 kilometers across. It was not sampled by the Apollo program, so a precise age has not been determined. However, geological mapping indicates that it is intermediate in age between the Imbrium and Nectaris Basins, suggesting an...
. The formation has been inundated 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...
during the formation of the mare
Lunar mare
The lunar maria are large, dark, basaltic plains on Earth's Moon, formed by ancient volcanic eruptions. They were dubbed maria, Latin for "seas", by early astronomers who mistook them for actual seas. They are less reflective than the "highlands" as a result of their iron-rich compositions, and...
, so only the rim and the multiple central peaks remain above the surface. The outer rim is worn and eroded, although it retains a generally circular form. A smaller crater Gassendi A intrudes into the northern rim, and joins a rough uplift at the northwest part of the floor. The crater pair bears a curious resemblance to a diamond ring.
In the southern part of the crater floor is a semi-circular ridge-like formation that is concentric with the outer rim. It is in the southern part where the rim dips down to its lowest portion, and a gap appears at the most southern point. The rim varies in height from as little as 200 meters to as high as 2.5 kilometers above the surface. The floor has numerous hummocks and rough spots. There is also a system of rille
Rille
Rille is typically used to describe any of the long, narrow depressions in the lunar surface that resemble channels. Typically a rille can be up to several kilometers wide and hundreds of kilometers in length...
s that criss-cross the floor, named the Rimae Gassendi.
On some older maps the crater Gassendi A was called Clarkson, after the British amateur astronomer and selenographer Roland L T Clarkson, but this name is not officially recognized 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...
and the name has been removed.
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 Gassendi.| Gassendi | Latitude | Longitude | Diameter |
|---|---|---|---|
| A | 15.5° S | 39.7° W | 33 km |
| B | 14.7° S | 40.6° W | 26 km |
| E | 18.4° S | 43.5° W | 8 km |
| F | 15.0° S | 45.0° W | 8 km |
| G | 16.8° S | 44.6° W | 8 km |
| J | 21.6° S | 37.0° W | 9 km |
| K | 18.7° S | 43.6° W | 6 km |
| L | 20.4° S | 41.8° W | 6 km |
| M | 18.6° S | 39.0° W | 3 km |
| N | 18.0° S | 39.2° W | 3 km |
| O | 21.9° S | 35.1° W | 11 km |
| P | 17.2° S | 40.6° W | 2 km |
| R | 21.9° S | 37.7° W | 3 km |
| T | 19.0° S | 35.4° W | 10 km |
| W | 17.6° S | 43.7° W | 6 km |
| Y | 20.8° S | 38.3° W | 5 km |
External links
- Trimley's Moon Man - Roland Clarkson (accessed 9/16/05)