1967 photograph made by NASA's Lunar Orbiter 4

Like a target ring bull's-eye, the lunar mare Mare Orientale (the "eastern sea") is one of the most striking large scale lunar features. Located on the extreme western edge of the lunar nearside, this impact basin is unfortunately difficult to see from an Earthbound perspective. From http://antwrp. ... From http://antwrp. ... NASA Logo Listen to this article · (info) This audio file was created from the revision dated 2005-09-01, and does not reflect subsequent edits to the article. ... Lunar Orbiter 4 was designed to take advantage of the fact that the three previous Lunar Orbiters had completed the required needs for Apollo mapping and site selection. ... A map showing the location of Mare Imbrium The Lunar maria (singular: mare, pronounced MAH-ray) are large, dark, basaltic plains on Earths Moon, formed by ancient basaltic flood eruptions caused by extremely large meteoroid impacts. ... Crust composition Oxygen 43% Silicon 21% Aluminium 10% Calcium 9% Iron 9% Magnesium 5% Titanium 2% Nickel 0. ... This article is about impact craters, also known as meteor craters. ...

Material from this basin was not sampled by the Apollo program, so the basin's precise age is not known. However, it is the freshest impact basin on the Moon and is believed to be slightly younger than the Imbrium Basin, which formed about 3.85 billion years ago. The surrounding basin material is of the Lower Imbrian epoch, with the mare material being of the Upper Imbrian epoch. Oblique view of Mare Imbrium looking south towards Copernicus crater. ... In the Lunar geologic timescale, the Lower Imbrian epoch occurred between 3850 million years ago to about 3800 million years ago. ... The word epoch can mean either an interval of time, or a particular point in time used as a reference point. ... In the Lunar geologic timescale, the Upper Imbrian epoch occurred between 3800 million years ago to about 3200 million years ago. ...

The mare is about 600 miles (900 km) across and was formed by the impact of an asteroid sized object. Unlike most other basins on the Moon, Orientale is relatively unflooded by mare basalts, exposing much of the basin structure to view; the central portion of Mare Orientale is covered by a thin layer of mare basalt probably less than 1 kilometer deep, much less than in other nearside mare basins. The collision caused ripples in the lunar crust resulting in the three concentric circular features. The innermost rings of this vast, multi-ringed crater are the inner and outer Montes Rook, and the outermost ring are the Montes Cordillera, 930 km in diameter. Basin ejecta begins just outside the Montes Cordillera and extends up to 500 kilometers beyond the base of the mountains. This ejecta has a rough, hummocky texture and contains linear patterns that point back at the center of Orientale. Basalt Basalt is an extrusive igneous rock, sometimes porphyritic, and is often both fine-grained and dense. ... Montes Rook is a ring-shaped mountain range that lies along the western limb of the Moon, crossing over to the far side. ... Montes Cordillera is a mountain range on the Moon. ...

Name

This feature is believed to have first been given its modern name by the German astronomer Julius Franz in his 1906 book Der Mond. However, in his book On the Moon, Patrick Moore later claimed to have discovered and named this same feature in 1946. During the 1960s, rectified images of this area by Gerard Kuiper at the Lunar and Planetary Laboratory gave rise to the notion of this being an impact crater. An astronomer or astrophysicist is a scientist whose area of research is astronomy or astrophysics. ... Julius Heinrich Franz (1847–1913) was a German astronomer. ... 1906 (MCMVI) was a common year starting on Monday (see link for calendar). ... This article is about Patrick Moore, the astronomer. ... 1946 (MCMXLVI) was a common year starting on Tuesday. ... The 1960s in its most obvious sense refers to the decade between 1960 and 1969, but the expression has taken on a wider meaning over the past twenty years. ... Gerard Kuiper, circa 1963. ...

At the time this formation was named, it was located on what by convention was considered the eastern side of the Moon. Hence the latin name for "Eastern Sea". In 1961, however, the International Astronomical Union adopted the "astronautic convention" and this limb became the western edge. Latin is an ancient Indo-European language originally spoken in the region around Rome called Latium. ... 1961 (MCMLXI) was a common year starting on Sunday (link will take you to calendar). ... Logo of the IAU The International Astronomical Union (IAU) unites national astronomical societies from around the world. ...

External links

• Who Discovered Orientale?