Mare Nectaris (Latin ''nectaris'', the "Sea of Nectar") is a small lunar mare or sea (a volcanic lava plain noticeably darker than the rest 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 ...

's surface) located south of Mare Tranquillitatis southwest of Mare Fecunditatis, on the near side of the moon. Montes Pyrenaeus borders the mare to the east and Sinus Asperitatis fuses to its northwestern edge. It is 84,000 square kilometers in size. Several large craters are situated at the borders of Mare Nectaris. The biggest one is lava-filled

Fracastorius ''Fracastorius'' is a genus of Asian seed bugs in the tribe Homoeocerini, erected by William Lucas Distant in 1901. It contains the species ''Fracastorius cornutus ''Fracastorius'' is a genus of Asian seed bugs in the tribe Homoeocerini, e ...

(124 km), which fuses with southern coast of the Sea. A prominent trio of 100-km craters Theophilus,

Cyrillus Cyrillus, Greek jurist of the 5th century, was a professor in the ancient Law School of Berytus (present-day Beirut), and one of the founders of the oecumenical school of jurists (τῆς οἰκουμένης διδάσκαλοι). This school pr ...

and

Catharina Catharina is a feminine given name, the Dutch and Swedish spelling of the name Catherine. In the Netherlands, people use a great number of short forms in daily life, including ''Carine'', ''Catelijne'', ''Cato'', ''Ina'', ''Ineke'', ''Kaat'', ''Kaa ...

is located near northwestern coast. Other notable feature is a "

ghost crater A palimpsest , in planetary astronomy, is an ancient crater that has been degraded over time. They may also be referred to as "ghost craters", "degraded craters", "buried craters", or "pathological craters". Palimpsests have been identified on M ...

" Daguerre, almost entirely covered with lava, in the northern part of Mare Nectaris. Mare Nectaris is located in the central part of 860-km-diameter impact basin, which was formed 3.8–3.9 billion years ago. This event marks the beginning of

Nectarian The Nectarian Period of the lunar geologic timescale runs from 3920 million years ago to 3850 million years ago. It is the period during which the Nectaris Basin and other major basins were formed by large impact events. Ejecta from Nectaris fo ...

period of the

lunar geologic timescale The lunar geological timescale (or selenological timescale) divides the history of Earth's Moon into five generally recognized periods: the Copernican, Eratosthenian, Imbrian ( Late and Early epochs), Nectarian, and Pre-Nectarian. The boundarie ...

. The best-preserved part of the rim of this basin is called

Rupes Altai Rupes Altai is an escarpment in the lunar surface that is located in the southeastern quadrant of the Moon's near side. It is named for the Altai Mountains in Asia, and is the most prominent lunar escarpment. The selenographic coordinates of this f ...

, in the southwest part of the basin. Lava filling of Mare Nectaris is younger than the basin itself. The mare material is approximately 1000m in depth, and mainly of the

period and the Lower Imbrian epoch, with the mare material of the

Upper Imbrian The Imbrian is a lunar geologic period divided into two epochs, the Early and Late. Early Imbrian In the lunar geologic timescale, the Early Imbrian epoch occurred from 3,850 million years ago to about 3,800 million years ago. It overlaps the end ...

epoch. The crater Theophilus on the northeastern side of the mare is of the Eratosthenian period. Thus, the crater is younger than the mare to its southeast. Enough subsidence has occurred to open a few arcuate

graben In geology, a graben () is a depressed block of the crust of a planet or moon, bordered by parallel normal faults. Etymology ''Graben'' is a loan word from German, meaning 'ditch' or 'trench'. The word was first used in the geologic conte ...

s on the western margin of the mare. A mass concentration (mascon), or gravitational high, was identified in the center of Mare Nectaris from Doppler tracking of the five Lunar Orbiter spacecraft in 1968. The mascon was confirmed and mapped at higher resolution with later orbiters such as Lunar Prospector and GRAIL. File:Mare Nectaris (LRO).png, Basin of Mare Nectaris ( LRO image mosaic).

is a thin bright streak in the lower left File:Mare Nectaris (GLD100).jpg, Topographic map of the same area ( LRO data) File:Nectaris basin GRAIL gravity.jpg, Gravity map based on GRAIL File:Mare Nectaris AS11-42-6241.jpg, Oblique view facing southeast, from

Apollo 11 Apollo 11 (July 16–24, 1969) was the American spaceflight that first landed humans on the Moon. Commander Neil Armstrong and lunar module pilot Buzz Aldrin landed the Apollo Lunar Module ''Eagle'' on July 20, 1969, at 20:17 UTC, ...

. The large crater right of center is Theophilus, and Mädler is to its left.

is near the central horizon, and the white mountain on the horizon at right is part of the Rupes Altai. The teardrop-shaped crater in the lower left is Torricelli.

References

{{Lunar maria Nectaris Nectaris Nectaris

See also

References