Rupes Altai is an

escarpment An escarpment is a steep slope or long cliff that forms as a result of faulting or erosion and separates two relatively level areas having different elevations. Due to the similarity, the term '' scarp'' may mistakenly be incorrectly used inte ...

in the lunar surface that is located in the southeastern quadrant of the

Moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...

's near side. It is named for the

Altai Mountains The Altai Mountains (), also spelled Altay Mountains, are a mountain range in Central Asia, Central and East Asia, where Russia, China, Mongolia, and Kazakhstan converge, and where the rivers Irtysh and Ob River, Ob have their headwaters. The ...

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

, and is the most prominent lunar escarpment. The selenographic coordinates of this feature are , and it has a length of about 427 km. The southeastern end of the cliff terminates along the western edge of the crater

Piccolomini The House of Piccolomini (pronounced ) is the name of an Italian noble family, Patricians of Siena, who were prominent from the beginning of the 13th century until the 18th century. The family achieved the recognized titles of Pope of the Catho ...

. It then arcs irregularly towards the north, climbing to heights of nearly a kilometer. The northern end of the arc is an irregular region with no clearly defined terminus, where it brackets the prominent craters

Theophilus Theophilus is a male given name with a range of alternative spellings. Its origin is the Greek word Θεόφιλος from θεός (''theós'', "God") and φιλία (''philía'', "love or affection") can be translated as "Love of God" or "Friend ...

, Cyrillus, and Catharina. This cliff forms the southwestern rim of the Nectaris impact basin. This feature is difficult to locate during the full moon when the sunlight is nearly overhead. It appears as a bright, winding line about five days after the

new moon In astronomy, the new moon is the first lunar phase, when the Moon and Sun have the same ecliptic longitude. At this phase, the lunar disk is not visible to the naked eye, except when it is silhouetted against the Sun during a solar eclipse. ...

, and casts a long, irregular shadow about four days after the full moon, when the sunset terminator is nearby and the sunlight is arriving at a low angle.

References

External links

Lunar Orbiter 4 Lunar Orbiter 4 was a robotic U.S. spacecraft, part of the Lunar Orbiter program, Lunar Orbiter Program, designed to orbit the Moon, after the three previous orbiters had completed the required needs for Project Apollo, Apollo mapping and site s ...

br>image showing most of Rupes Altai
(Lunar and Planetary Institute) * * * * Escarpments on the Moon {{Escarpments on the Moon