
Oceanus Procellarum ( ; from ) is a vast
lunar mare
The lunar maria ( ; mare ) are large, dark, basaltic plains on Earth's Moon, formed by lava flowing into ancient impact basins. They are less reflective than the "highlands" as a result of their iron-rich composition, and hence appear dark to ...
on the western edge of the
near side 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 ...
. It is the only one of the lunar maria to be called an "
Oceanus
In Greek mythology, Oceanus ( ; , also , , or ) was a Titans, Titan son of Uranus (mythology), Uranus and Gaia, the husband of his sister the Titan Tethys (mythology), Tethys, and the father of the River gods (Greek mythology), river gods ...
" (ocean), due to its size: Oceanus Procellarum is the largest of the maria ("seas"), stretching more than across its north–south axis and covering roughly , accounting for 10.5% of the total lunar surface area.
Characteristics
Like all lunar maria, Oceanus Procellarum was formed by ancient
volcanic
A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.
On Earth, volcanoes are most often fo ...
eruptions resulting in
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 ...
ic floods that covered the region in a thick, nearly flat layer of solidified
magma
Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma (sometimes colloquially but incorrectly referred to as ''lava'') is found beneath the surface of the Earth, and evidence of magmatism has also ...
. Basalts in Oceanus Procellarum have been estimated to be as young as one billion years old. Unlike the other lunar maria, however, Oceanus Procellarum may or may not be contained within a single, well-defined impact basin.
Around its edges lie many minor bays and seas, including
Sinus Roris
Sinus Roris (Latin ''sinus rōris'' "Bay of Dew") is a dark, basaltic plain on the near side of the Moon that forms an extension of the northern edge of Oceanus Procellarum. The IAU-defined selenographic coordinates of this bay are 54.0° N, ...
to the north, and
Mare Nubium
Mare Nubium (Latin ''nūbium'', the "sea of clouds") is a lunar mare in the Nubium basin on the Moon's near side. The mare is located just to the southeast of Oceanus Procellarum.
Formation
The basin containing Mare Nubium is believed to ...
,
Mare Humorum
Mare Humorum (Latin ''hūmōrum'', the "Sea of Moisture" or "Sea of Humors") is a lunar mare. The impact basin it is located in is across.
Geology
It was not sampled by the Apollo program, so a precise age has not been determined. However, ...
and to the south. To the northeast, Oceanus Procellarum is separated from
Mare Imbrium
Mare Imbrium (Latin ''imbrium'', the "Sea of Showers" or "Sea of Rains") is a vast lunar mare, lava plain within the Imbrium Basin on the Moon and is one of the larger craters in the Solar System. The Imbrium Basin formed from the collision ...
by the
Carpathian Mountains
The Carpathian Mountains or Carpathians () are a range of mountains forming an arc across Central Europe and Southeast Europe. Roughly long, it is the third-longest European mountain range after the Ural Mountains, Urals at and the Scandinav ...
. On its north-west edge lies the 32 km wide
Aristarchus ray crater, the brightest feature on the Near side of the Moon. Also, the more-prominent ray-crater
Copernicus
Nicolaus Copernicus (19 February 1473 – 24 May 1543) was a Renaissance polymath who formulated a mathematical model, model of Celestial spheres#Renaissance, the universe that placed heliocentrism, the Sun rather than Earth at its cen ...
lies within the eastern edge of the mare, distinct with its bright ray materials sprawling over the darker material.
Origin
There are several hypotheses about the origin of Oceanus Procellarum and a related asymmetry between the near and far sides of the Moon. One of the most likely is that Procellarum was a result of an ancient giant impact on the near side of the Moon. The size of the impact basin has been estimated to be more than 3,000 kilometers, which would make it
one of the three largest craters in the Solar System.
The impact likely happened very early in the Moon's history: at the time when
magma ocean
Magma oceans are vast fields of surface magma that exist during periods of a planet's or some natural satellite's accretion when the celestial body is completely or partly molten.
In the early Solar System, magma oceans were formed by the melt ...
still existed or just ceased to exist. It deposited 5–30 km of crustal material on the far side forming highlands. If this is the case, all impact related structures such as crater
rim
Rim may refer to:
*Rim (basketball), the hoop through which the ball must pass
**Breakaway rim, a sprung basketball rim
* Rim (coin), the raised edge which surrounds the coin design
* Rim (crater), extending above the local surface
*Rim (firearms) ...
, central peak etc. have been obliterated by later impacts and
volcanism
Volcanism, vulcanism, volcanicity, or volcanic activity is the phenomenon where solids, liquids, gases, and their mixtures erupt to the surface of a solid-surface astronomical body such as a planet or a moon. It is caused by the presence of a he ...
. One piece of evidence in support of this hypothesis is concentration of incompatible elements (
KREEP
KREEP, an acronym built from the letters K (the atomic symbol for potassium), REE (rare-earth elements) and P (for phosphorus), is a geochemical component of some lunar impact breccia and basaltic rocks. Its most significant feature is somewhat e ...
) and low calcium
pyroxene
The pyroxenes (commonly abbreviated Px) are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. Pyroxenes have the general formula , where X represents ions of calcium (Ca), sodium (Na), iron ( ...
around Oceanus Procellarum.
Procellarum may have also been formed by spatially inhomogeneous heating during the Moon's formation.
[ The GRAIL mission, which mapped the gravity gradients of the Moon, found square formations resembling rift valleys surrounding the region beneath the lava plains, suggesting the basin was formed by heating and cooling of the lunar surface by internal processes rather than by an impact, which would have left a round crater.]
Other hypotheses include a late accretion of a companion Moon on the far side. The latter postulates that in addition to the present Moon, another smaller (about 1,200 km in diameter) moon was formed from debris of the giant impact
The giant-impact hypothesis, sometimes called the Theia Impact, is an astrogeology hypothesis for the formation of the Moon first proposed in 1946 by Canadian geologist Reginald Daly. The hypothesis suggests that the Early Earth collided wit ...
. After a few tens of millions of years it collided with the Moon and due to a small collisional velocity simply piled up on one side of the Moon forming what is now known as far side highlands
Highland is a broad term for areas of higher elevation, such as a mountain range or mountainous plateau.
Highland, Highlands, or The Highlands, may also refer to:
Places Africa
* Highlands, Johannesburg, South Africa
* Highlands, Harare, Zimbab ...
.
Late lunar volcanism
Relatively recent (less than 2 bya) volcanic activity had been suspected in the Oceanus Procellarum due to the presence of relatively uneroded features. The 2020 Chang'e-5 sample return mission provided constraints on the age of Oceanus Procellarum, finding it to be 1963 ± 57 million years old – over a billion years younger than any other previously returned lunar sample. Late lunar volcanic activity was considered surprising as the Moon is much smaller than Earth; interior heat necessary for volcanism should have been lost three billion years ago, so volcanic rocks as late as those found in Oceanus Procellarum must require additional heat sources.
Previous studies suggested that Oceanus Procellarum should have high concentrations of the heat-producing elements such as potassium, thorium, and uranium, but samples returned showed that the concentration of suspected radioactive elements is much lower than necessary to provide prolonged heating.
Exploration
The robotic
Robotics is the interdisciplinary study and practice of the design, construction, operation, and use of robots.
Within mechanical engineering, robotics is the design and construction of the physical structures of robots, while in computer s ...
lunar probes Luna 9
Luna 9 (Луна-9), internal designation Ye-6 No.13, was an uncrewed space mission of the Soviet Union's Luna programme. On 3 February 1966, the Luna 9 spacecraft became the first spacecraft to achieve a soft landing on the Moon and return ima ...
, Luna 13
Luna 13 (E-6M series) was an uncrewed space mission of the Luna program by Soviet Union.
Overview
The Luna 13 spacecraft was launched toward the Moon onboard a Molniya-M and accomplished a soft landing on 24 December 1966, in the region of Oc ...
, Surveyor 1
Surveyor 1 was the first lunar soft-lander in the uncrewed Surveyor program of the National Aeronautics and Space Administration (NASA, United States). This lunar soft-lander gathered data about the lunar surface that would be needed for the c ...
and Surveyor 3
Surveyor 3 is the third lander of the American uncrewed Surveyor program sent to explore the surface of the Moon in 1967 and the second to successfully land. It was the first mission to carry a surface-soil sampling-scoop.
Surveyor 3 was vis ...
landed in Oceanus Procellarum. Luna 9 landed southwest of Galilaei crater in 1966. Luna 13 landed southeast of Seleucus
Seleucus or Seleukos (Ancient Greek: Σέλευκος) was a Macedonia (ancient kingdom), Macedonian Greek name, possibly meaning "very bright" or “very white”. It is likely related to the ancient name Zaleucus (Ancient Greek language, Ancient ...
crater, later in 1966. Surveyor 1 landed north of Flamsteed crater (within the larger Flamsteed P) in 1966, and Surveyor 3 landed in 1967. The Chinese
Chinese may refer to:
* Something related to China
* Chinese people, people identified with China, through nationality, citizenship, and/or ethnicity
**Han Chinese, East Asian ethnic group native to China.
**'' Zhonghua minzu'', the supra-ethnic ...
probe Chang'e 5
Chang'e 5 () was the fifth lunar exploration mission in the Chinese Lunar Exploration Program of CNSA, and China's first lunar sample-return mission. Like its predecessors, the spacecraft is named after the Chinese moon goddess, Chang'e. ...
landed at Statio Tianchuan on Mons Rümker
Mons Rümker is an isolated volcanic formation that is located in the northwest part of the Moon's near side, at selenographic coordinates 40.8° N, 58.1° W. The feature forms a large, elevated mound in the northern part of the Oceanus Procellar ...
in Oceanus Procellarum in December 2020 and collected of lunar rock samples.
During the Apollo program, flight operations planners were concerned about having the optimum lighting conditions at the landing site, hence the alternative target sites moved progressively westward, following the terminator. A delay of two days for weather or equipment reasons would have sent Apollo 11 to Sinus Medii
Sinus Medii (Latin ''sinus mediī'' "Middle Bay") is a small lunar mare. It takes its name from its location at the intersection of the Moon's equator and prime meridian; as seen from the Earth, this feature is located in the central part of the ...
(designated ALS3) instead of ALS2—Mare Tranquillitatis
Mare Tranquillitatis (Latin for Sea of Tranquillity or Sea of Tranquility) is a lunar mare that sits within the Tranquillitatis basin on the Moon. It contains Tranquility Base, the first location on another celestial body to be visited by huma ...
; another two-day delay would have resulted in ALS5, a site in Oceanus Procellarum, being targeted.
During the November 1969 Apollo 12
Apollo 12 (November 14–24, 1969) was the sixth crewed flight in the United States Apollo program and the second to land on the Moon. It was launched on November 14, 1969, by NASA from the Kennedy Space Center in Florida. Commander Charles ...
mission, astronaut
An astronaut (from the Ancient Greek (), meaning 'star', and (), meaning 'sailor') is a person trained, equipped, and deployed by a List of human spaceflight programs, human spaceflight program to serve as a commander or crew member of a spa ...
s (Charles) Pete Conrad
Charles "Pete" Conrad Jr. (June 2, 1930 – July 8, 1999) was an American NASA astronaut, aeronautical engineer, naval officer, aviator, and test pilot who commanded the Apollo 12 mission, on which he became the third person to walk on t ...
and Alan Bean
Alan LaVern Bean (March 15, 1932 – May 26, 2018) was an American naval officer and aviator, aeronautical engineer, test pilot, NASA astronaut and painter. He was selected to become an astronaut by NASA in 1963 as part of Astronaut Grou ...
landed the Lunar Module (LM) ''Intrepid'' nearly 165 meters from Surveyor 3 in Oceanus Procellarum. Their landing site has become known as Statio Cognitum (Latin, "to be known from experience").
In popular culture
*In the 2004 album ''Sirens
Siren or sirens may refer to:
Common meanings
* Siren (alarm), a loud acoustic alarm used to alert people to emergencies
* Siren (mythology), an enchanting but dangerous monster in Greek mythology that lured sailors to their deaths.
Places
* Si ...
'' by Greek metal band Astarte
Astarte (; , ) is the Greek language, Hellenized form of the Religions of the ancient Near East, Ancient Near Eastern goddess ʿAṯtart. ʿAṯtart was the Northwest Semitic languages, Northwest Semitic equivalent of the East Semitic language ...
, there is a song named after the lunar mare.
See also
* Apollo 18
*Aristarchus (crater)
Aristarchus is a Lunar craters, lunar impact crater that lies in the northwest part of the Moon's near side. It is considered the brightest of the large formations on the lunar surface, with an albedo nearly double that of most lunar features. ...
* Human Lunar Return study
*Mare Cognitum
Mare Cognitum (Latin ''cognitum'', the "Sea that has Become Known") is a lunar mare located in a basin or large Impact crater, crater which sits in the second ring of Oceanus Procellarum. To the northwest of the mare is the Montes Riphaeus mounta ...
*Volcanism on the Moon
Volcanism on the Moon is represented by the presence of volcanoes, pyroclastic rock, pyroclastic deposits and vast lava plains on the lunar surface. The volcanoes are typically in the form of small domes and cones that form large volcanic complexe ...
References
External links
*
{{Portal bar, Astronomy, Stars, Spaceflight, Outer space, Solar System
Procellarum
Apollo 12