Oceanus Procellarum ( la, Ōceanus procellārum, lit=Ocean of Storms) is a vast
lunar mare
The lunar maria (; singular: mare ) are large, dark, basaltic plains on Earth's Moon, formed by ancient asteroid impacts on the far side on the Moon that triggered volcanic activity on the opposite (near) side. They were dubbed , Latin for 'seas' ...
on the western edge of the
near side 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 ...
. It is the only one of the lunar maria to be called an "
Oceanus
In Greek mythology, Oceanus (; grc-gre, , Ancient Greek pronunciation: , also Ὠγενός , Ὤγενος , or Ὠγήν ) was a Titan son of Uranus and Gaia, the husband of his sister the Titan Tethys, and the father of the river gods a ...
" (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 a rupture 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 found where tectonic plates a ...
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 is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural sa ...
. 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, 56 ...
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 ha ...
and
Mare Humorum
Mare Humorum (Latin ''hūmōrum'', the "Sea of Moisture") is a lunar mare. The impact basin it is located in is 425 kilometers across.
Geology
It was not sampled by the Apollo program, so a precise age has not been determined. However, geologic ...
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", "Sea of Tears") is a vast 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 colli ...
by the
Carpathian Mountains
The Carpathian Mountains or Carpathians () are a range of mountains forming an arc across Central Europe. Roughly long, it is the third-longest European mountain range after the Urals at and the Scandinavian Mountains at . The range stretches ...
. 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 (; pl, Mikołaj Kopernik; gml, Niklas Koppernigk, german: Nikolaus Kopernikus; 19 February 1473 – 24 May 1543) was a Renaissance polymath, active as a mathematician, astronomer, and Catholic canon, who formulated ...
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.
![Apollo 12 landing site 3154 h2](https://upload.wikimedia.org/wikipedia/commons/4/49/Apollo_12_landing_site_3154_h2.jpg)
The impact likely happened very early in the Moon's history: at the time when
magma ocean Magma oceans exist during periods of Earth's or any planet's accretion when the planet is completely or partly molten.
In the early Solar System, magma oceans were formed by the melting of planetesimals and planetary impacts. Small planetesimals a ...
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, central peak etc. have been obliterated by later impacts and
volcanism
Volcanism, vulcanism or volcanicity is the phenomenon of eruption of molten rock (magma) onto the surface of the Earth or a solid-surface planet or moon, where lava, pyroclastics, and volcanic gases erupt through a break in the surface called ...
. 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 to ''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 calcium (Ca), sodium (Na), iron (Fe II) ...
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 Big Splash, or the Theia (planet), Theia Impact, suggests that the Moon formed from the ejecta of a collision between the proto-Earth and a Mars-sized planet, approximately 4.5 billion years ago ...
. 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 Albania
* Dukagjin Highlands
Armenia
* Armenian Highlands
Australia
*Sou ...
.
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 an interdisciplinarity, interdisciplinary branch of computer science and engineering. Robotics involves design, construction, operation, and use of robots. The goal of robotics is to design machines that can help and assist human ...
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 survivable landing on a celestial bod ...
, Luna 13
Luna 13 (E-6M series) was an unmanned space mission of the Luna program.
Overview
The Luna 13 spacecraft was launched toward the Moon from an Earth-orbiting platform and accomplished a soft landing on 24 December 1966, in the region of Oceanus P ...
, 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 cre ...
and Surveyor 3
Surveyor 3 was the third lander of the American uncrewed Surveyor program sent to explore the surface of the Moon in 1967. It was the first mission to carry a surface-soil sampling-scoop.
Surveyor 3 was visited by Apollo 12 astronauts Pete Con ...
landed in Oceanus Procellarum. Luna 9 landed southwest of Galilaei crater in 1966. Luna 13 landed southeast of Seleucus crater, later in 1966. Surveyor 1 landed north of Flamsteed
John Flamsteed (19 August 1646 – 31 December 1719) was an English astronomer and the first Astronomer Royal. His main achievements were the preparation of a 3,000-star catalogue, ''Catalogus Britannicus'', and a star atlas called ''Atlas Coe ...
crater (within the larger Flamsteed P) in 1966, and Surveyor 3 landed in 1967. The Chinese
Chinese can refer to:
* Something related to China
* Chinese people, people of Chinese nationality, citizenship, and/or ethnicity
**''Zhonghua minzu'', the supra-ethnic concept of the Chinese nation
** List of ethnic groups in China, people of va ...
probe Chang'e 5
Chang'e 5 () was the fifth lunar exploration mission of the Chinese Lunar Exploration Program, and China's first lunar sample-return mission. Like its predecessors, the spacecraft is named after the Chinese moon goddess Chang'e. It launched ...
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 Procellaru ...
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 ''tranquillitātis'', the Sea of Tranquillity or Sea of Tranquility; see spelling differences) is a lunar mare that sits within the Tranquillitatis basin on the Moon. It is the first location on another world to be ...
; another two-day delay would have resulted in ALS5, a site in Oceanus Procellarum, being targeted.
During the 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, Florida. Commander Pete Conra ...
mission, astronaut
An astronaut (from the Ancient Greek (), meaning 'star', and (), meaning 'sailor') is a person trained, equipped, and deployed by a human spaceflight program to serve as a commander or crew member aboard a spacecraft. Although generally r ...
s (Charles) Pete Conrad
Charles "Pete" Conrad Jr. (June 2, 1930 – July 8, 1999) was an American NASA astronaut, aeronautical engineer, naval officer and aviator, and test pilot, and commanded the Apollo 12 space mission, on which he became the third person to ...
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 the fourth person to walk on the Moon. He was selected to become an astron ...
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").
See also
* Apollo 18
*Aristarchus (crater)
Aristarchus is a 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. The feature is ...
*Human Lunar Return study
NASA began its "Human Lunar Return study" in September 1995 to identify ways it could conduct future human spaceflight missions to the Moon. The final Human Lunar Return (HLR) briefing took place on August 7, 1996. The study was seen as laying "the ...
*Mare Cognitum
Mare Cognitum (Latin ''cognitum'', the "Sea that has Become Known") is a lunar mare located in a basin or large crater which sits in the second ring of Oceanus Procellarum. To the northwest of the mare is the Montes Riphaeus mountain range, part ...
*Volcanism on the Moon
Volcanism on the Moon is represented by the presence of volcanoes, 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 complexes and isolated edi ...
References
{{Portal bar, Astronomy, Stars, Spaceflight, Outer space, Solar System
Procellarum
Apollo 12