Theophilus is a prominent

lunar Lunar most commonly means "of or relating to the Moon". Lunar may also refer to: Arts and entertainment * ''Lunar'' (series), a series of video games * "Lunar" (song), by David Guetta * "Lunar", a song by Priestess from the 2009 album ''Prior t ...

impact crater An impact crater is a depression (geology), depression in the surface of a solid astronomical body formed by the hypervelocity impact event, impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal c ...

that lies between Sinus Asperitatis in the north and

Mare Nectaris 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's surface) located south of Mare Tranquillitatis southwest of Mare Fecunditatis, on the near ...

to the southeast. It partially intrudes into the comparably sized crater Cyrillus to the southwest. To the east is the smaller crater Mädler and further to the south-southeast is Beaumont. It was named after the 4th-century Coptic Pope Theophilus I of Alexandria.''Autostar Suite Astronomer Edition''. CD-ROM. Meade, April 2006. Theophilus, Cyrillus and Catharina form a prominent group of large craters visible on the terminator 5 days after the new moon.

Description

The rim of Theophilus has a wide,

terrace Terrace may refer to: Landforms and construction * Fluvial terrace, a natural, flat surface that borders and lies above the floodplain of a stream or river * Terrace, a street suffix * Terrace, the portion of a lot between the public sidewalk a ...

d inner surface that shows indications of landslips. It is 4200 metres deep with massive walls and has broken into a second formation, Cyrillus. It was created during the

Eratosthenian The Eratosthenian period in the lunar geologic timescale runs from 3,200 million years ago to 1,100 million years ago. It is named after the crater Eratosthenes, which displays characteristics typical of craters of this age, including a surface ...

period, from 3.2 to 1.1 billion years ago. It has an imposing central mountain, 1,400 metres high, with four summits. The floor of the crater is relatively flat, and it has a large, triple-peaked central mountain that climbs to a height of about 2 kilometres above the floor. The western peak is designated Psi (ψ), the eastern Phi (φ), and the northern peak is Alpha (α) Theophilus. The western slopes of this ridge are wider and more irregular, whereas the peaks descend more sharply to the floor on the northern and western faces. The

Apollo 16 Apollo 16 (April 1627, 1972) was the tenth human spaceflight, crewed mission in the United States Apollo program, Apollo space program, administered by NASA, and the fifth and penultimate to Moon landing, land on the Moon. It was the second o ...

mission collected several pieces of

basalt Basalt (; ) is an aphanite, 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 planetary surface, surface of a terrestrial ...

that are believed to be ejecta from the formation of Theophilus.

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 Theophilus.

External links

*
Central Peak Bedrock
from LROC

References

{{Reflist Impact craters on the Moon Eratosthenian