Mersenius is a lunar

impact crater An impact crater is a circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact crater ...

that is located to the west of the

Mare Humorum Mare Humorum (Latin ''hūmōrum'', the "Sea of Moisture") is a lunar mare. The impact basin it is located in is 425 kilometers across. Geology It was not sampled by the Apollo program, so a precise age has not been determined. However, geologi ...

, in the southwestern part of the

Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...

. To the southwest is the crater

Cavendish Cavendish may refer to: People * The House of Cavendish, a British aristocratic family * Margaret Cavendish (1623–1673), British poet, philosopher, and scientist * Cavendish (author) (1831–1899), pen name of Henry Jones, English au ...

, and to the south-southeast lies

Liebig Justus Freiherr von Liebig (12 May 1803 – 20 April 1873) was a German scientist who made major contributions to agricultural and biological chemistry, and is considered one of the principal founders of organic chemistry. As a professor at t ...

. Mersenius is 84 kilometers in diameter and 2.3 kilometers deep. It is from the Nectarian period, 3.92 to 3.85 billion years ago. The rim of Mersenius is heavily worn, especially in the low northern section. The crater Mersenius N lies across the southwestern rim. The interior has been flooded by

basalt Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90 ...

lava Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or un ...

, which bulges upwards forming a

convex Convex or convexity may refer to: Science and technology * Convex lens, in optics Mathematics * Convex set, containing the whole line segment that joins points ** Convex polygon, a polygon which encloses a convex set of points ** Convex polytop ...

domed shape with an estimated height of 450 metres relative to the floor edges. This was most likely formed by lava upwelling beneath the surface. There are several tiny craters across the floor surface, but little in the way of a central peak. At least two faint

rille Rille (German for 'groove') 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 several kilometers wi ...

s lie along the surface of the floor. To the east of the crater on the surface and edges of the Mare Humorum is a

system designated Rimae Mersenius. These rilles are generally parallel and run to the north-northeast for a length of about 230 kilometers. The crater was named after the 17th-century French philosopher and physicist Marin Mersenne in 1935.

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 Mersenius.

References

* {{cite web , last = Wood , first = Chuck , date = October 13, 2006 , url = http://www.lpod.org/?m=20061013 , title = Mercy, Mersenius , publisher = Lunar Photo of the Day , accessdate = 2006-10-13 , url-status = dead , archiveurl = https://web.archive.org/web/20070927004747/http://www.lpod.org/?m=20061013 , archivedate = September 27, 2007 Impact craters on the Moon Nectarian