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Listed below are the largest ocean, lakes and seas in the Solar System and beyond includes single bodies of water or other liquid on or near the surface of a solid round body (terrestrial planet, planetoid, or moon).
Currently, cold surface bodies of liquid are found on two worlds in the Solar System, Earth and Saturn's moon Titan. [1] Earth is the only planet with liquid water on its surface. The other "oceans" are found under thick covers of surface ice. If both liquid and frozen water are counted, Earth ranks fifth in volume of its oceans. [2] Recent studies indicate a large underground saltwater ocean present on Ganymede, Jupiter’s largest moon, with estimated water volume eight times greater than Earth’s world ocean. [3]
The fourth largest of Jupiter’s moons, Europa, while smaller than Earth’s moon, ranks fourth in water volume, estimated to be twice more than on Earth. [2] Latest analysis using data from NASA’s James Webb Space Telescope indicates that the carbon dioxide found on the icy surface of Europa likely originated in the subsurface ocean which could potentially be habitable. [4]
Scientists predict "oceans" beneath the ice of the Jupiter's moon Callisto cratered surface and the south pole of Saturn's moon Enceladus. Saturn's moon Titan is also thought to have a salty subsurface ocean of water - as salty as the Dead Sea on Earth. [3] Additionally, research suggests that Saturn's moon Mimas might be hiding a liquid water ocean beneath its impact-battered surface. A subsurface ocean at Neptune's moon Triton is considered possible as well. Mysterious fault lines on dwarf planet Pluto may suggest that it has a hidden subsurface ocean. [3]
Lava lakes are found on Earth and Jupiter's moon Io. Subsurface oceans or seas are suspected to exist on some of Saturn's other moons, the asteroid Ceres, the larger trans-Neptunian objects, and ice planets in planetary systems.
Recent analysis of the interior of Ganymede suggests that it and some of the other icy bodies may not have a single interior global ocean but several stacked ones, separated by different phases of ice, with the lowest liquid layer adjacent to the rocky mantle below. [5] [6]
In June 2020, NASA scientists reported that it is likely that exoplanets with oceans may be common in the Milky Way galaxy, based on mathematical modeling studies of their internal heating rates. The majority of such worlds would probably have subsurface oceans, similar to those of the icy moons Europa and Enceladus. [7] [8]
Body | Type of object | Liquid volume in zetta liters [9] | Ocean/Lake/Sea | Composition | Location | Area (km2) | Average depth (km) | Image | Notes |
---|---|---|---|---|---|---|---|---|---|
Earth | planet (terrestrial) | 1.362 [10] | World Ocean | salt water | surface, global | 361,300,000 | 3.68 (max 11.02) | commonly divided into five regions 71% of Earth's surface | |
Caspian Sea | salt water | surface, Central Asia | 389,000 | 0.21 (max 1.02) | Earth's largest inland body of surface liquid, endorheic (0.07% of Earth's surface) | ||||
Lake Michigan–Huron | fresh water | surface, North America | 117,400 | 0.07 (max 0.28) | largest freshwater lake | ||||
Mars | planet (terrestrial) | ? | south polar lakes? (not confirmed) | salt water or brine? | subglacial, south polar cap | c. 200 | (shallow, > 0.2 m) | there may be additional such lakes [11] [12] | |
Io | moon of Jupiter | ? | Gish Bar Patera | lava | surface | 9,600 | ? | ||
Loki Patera | lava | surface | < 32,000 | ? | |||||
Europa | moon of Jupiter | 2.6 | (internal global ocean) | water? water–ammonia mixture? | subsurface, global | c. 30,000,000 | est. 50–100 | global ocean under 10 to 30 km of ice, perhaps twice the volume of Earth's ocean | |
Ganymede | moon of Jupiter | 35.4 | (internal global ocean) | salt water? | subsurface, global | c. 80,000,000 apiece | 100 | 100 km thick, under 150 km of ice, six times the volume of Earth's ocean; [13] possibly three oceans, one under another | |
Callisto | moon of Jupiter | 5.3 | (internal global ocean) | water? water–ammonia mixture? | subsurface, global | c. 65,000,000 | 10 | global ocean under 135 to 150 km of ice | |
Enceladus | moon of Saturn | 0.01 | (internal global ocean) | (salt?) water | subsurface, global | c. 650,000 | 26–31 or 38 ± 4 | global ocean under 21–26 or 23 ± 4 km of ice, based on libration [14] [15] | |
Dione | moon of Saturn | 0.14 | (internal global ocean?) | water? water–ammonia mixture? | subsurface, global | c. 2,700,000 | 65 ± 30 | global ocean under 99 ± 23 km of ice [15] | |
Rhea | moon of Saturn | ? | (internal global ocean?) | water? water–ammonia mixture? | subsurface, global | c. 1,000,000–2,000,000 | c. 15 | possible global ocean under the ice (c. 400 km) [lower-alpha 1] | |
Titan | moon of Saturn | 18.6 | Kraken Mare | hydrocarbons | surface, north polar region | ≈ 400,000 (0.5% of Titan's surface) | 0.85 (max) | largest known body of surface liquid beside Earth's Ocean; the northern Moray Sinus bay is the only part measured bathymetrically [18] | |
Ligeia Mare | predominantly methane, with small amounts of ethane and nitrogen [19] [20] | 126,000 | ~0.2 [21] | ||||||
Punga Mare | hydrocarbons | surface, north polar region | 61,000 | ~0.11 [21] | |||||
(internal global ocean) | water? water–ammonia mixture? | subsurface, global | c. 80,000,000 | < 300 | global ocean of water under < 100 km of ice | ||||
Titania | moon of Uranus | ? | (internal global ocean?) | water? water–ammonia mixture? | subsurface, global | c. 5,000,000 | c. 15–50 | possible global ocean under the ice (c. 150–200 km) | |
Oberon | moon of Uranus | ? | (internal global ocean?) | water? water–ammonia mixture? | subsurface, global | c. 3,000,000 | c. 15–40 | possible global ocean under the ice (c. 250 km) | |
Triton | moon of Neptune | 0.03 | (internal global ocean, ) | water? water–ammonia mixture? | subsurface, global | c. 20,000,000 | c. 150–200 | likely [22] global ocean under the ice (c. 150–200 km) | |
Pluto | dwarf planet (plutino) | 1 | (internal global ocean) | water? water–ammonia mixture? | subsurface, global | c. 10,000,000–15,000,000 | c. 100–180 | possible global ocean under the ice (c. 150–230 km) | |
Makemake | dwarf planet (cubewano) | ? | (internal global ocean?) | water? water–ammonia mixture? | subsurface, global | c. 3,000,000 | ? | possible global ocean under the ice | |
Gonggong | dwarf planet (SDO) | ? | (internal global ocean?) | water? water–ammonia mixture? | subsurface, global | c. 2,000,000–3,000,000 | ? | possible global ocean under the ice | |
Eris | dwarf planet (SDO) | ? | (internal global ocean?) | water? water–ammonia mixture? | subsurface, global | c. 10,000,000 | c. 150–200 | possible global ocean under the ice (c. 150–250 km) | |
Sedna | dwarf planet (sednoid) | ? | (internal global ocean?) | water? water–ammonia mixture? | subsurface, global | c. 1,000,000 | c. 15 | possible global ocean under the ice (c. 200 km) |
Callisto, or Jupiter IV, is the second-largest moon of Jupiter, after Ganymede. In the Solar System it is the third-largest moon after Ganymede and Saturn's largest moon Titan, and as large as the smallest planet Mercury, though only about a third as massive. Callisto is, with a diameter of 4,821 km, roughly a third larger than Earth's Moon and orbits Jupiter on average at a distance of 1,883,000 km, which is about six times further out than the Moon orbiting Earth. It is the outermost of the four large Galilean moons of Jupiter, which were discovered in 1610 with one of the first telescopes, being visible from Earth with common binoculars.
Europa, or Jupiter II, is the smallest of the four Galilean moons orbiting Jupiter, and the sixth-closest to the planet of all the 95 known moons of Jupiter. It is also the sixth-largest moon in the Solar System. Europa was discovered independently by Simon Marius and Galileo Galilei and was named after Europa, the Phoenician mother of King Minos of Crete and lover of Zeus.
Saturn is the sixth planet from the Sun and the second-largest in the Solar System, after Jupiter. It is a gas giant with an average radius of about nine-and-a-half times that of Earth. It has only one-eighth the average density of Earth, but is over 95 times more massive. Even though Saturn is nearly the size of Jupiter, Saturn has less than one-third of Jupiter's mass. Saturn orbits the Sun at a distance of 9.59 AU (1,434 million km) with an orbital period of 29.45 years.
Titan is the largest moon of Saturn and the second-largest in the Solar System. It is the only moon known to have an atmosphere denser than the Earth's, and is the only known object in space other than Earth on which clear evidence of stable bodies of surface liquid has been found. Titan is one of the seven gravitationally rounded moons of Saturn and the second-most distant among them. Frequently described as a planet-like moon, Titan is 50% larger than Earth's Moon and 80% more massive. It is the second-largest moon in the Solar System after Jupiter's moon Ganymede, and is larger than Mercury, but only 40% as massive due to Mercury being made of mostly dense iron and rock, while a large portion of Titan is made of less-dense ice.
Ganymede, or Jupiter III, is the largest and most massive natural satellite of Jupiter and in the Solar System. It is the largest Solar System object without a substantial atmosphere, despite being the only moon in the Solar System with a substantial magnetic field. Like Titan, Saturn's largest moon, it is larger than the planet Mercury, but has somewhat less surface gravity than Mercury, Io, or the Moon due to its lower density compared to the three.
Icy moons are a class of natural satellites with surfaces composed mostly of ice. An icy moon may harbor an ocean underneath the surface, and possibly include a rocky core of silicate or metallic rocks. It is thought that they may be composed of ice II or other polymorph of water ice. The prime example of this class of object is Europa.
Dione, also designated Saturn IV, is the fourth-largest moon of Saturn. With a mean diameter of 1,123 km and a density of about 1.48 g/cm3, Dione is composed of an icy mantle and crust overlying a silicate rocky core, with rock and water ice roughly equal in mass. Its trailing hemisphere is marked by large cliffs and scarps called chasmata; the trailing hemisphere is also significantly darker compared to the leading hemisphere.
Enceladus is the sixth-largest moon of Saturn and the 19th-largest in the Solar System. It is about 500 kilometers in diameter, about a tenth of that of Saturn's largest moon, Titan. It is mostly covered by fresh, clean ice, making it one of the most reflective bodies of the Solar System. Consequently, its surface temperature at noon reaches only −198 °C, far colder than a light-absorbing body would be. Despite its small size, Enceladus has a wide variety of surface features, ranging from old, heavily cratered regions to young, tectonically deformed terrain.
A cryovolcano is a type of volcano that erupts gases and volatile material such as liquid water, ammonia, and hydrocarbons. The erupted material is collectively referred to as cryolava; it originates from a reservoir of subsurface cryomagma. Cryovolcanic eruptions can take many forms, such as fissure and curtain eruptions, effusive cryolava flows, and large-scale resurfacing, and can vary greatly in output volumes. Immediately after an eruption, cryolava quickly freezes, constructing geological features and altering the surface.
An ocean world, ocean planet or water world is a type of planet that contains a substantial amount of water in the form of oceans, as part of its hydrosphere, either beneath the surface, as subsurface oceans, or on the surface, potentially submerging all dry land. The term ocean world is also used sometimes for astronomical bodies with an ocean composed of a different fluid or thalassogen, such as lava, ammonia or hydrocarbons. The study of extraterrestrial oceans is referred to as planetary oceanography.
Extraterrestrial liquid water is water in its liquid state that naturally occurs outside Earth. It is a subject of wide interest because it is recognized as one of the key prerequisites for life as we know it and is thus surmised to be essential for extraterrestrial life.
The habitability of natural satellites is the potential of moons to provide habitats for life, though it is not an indicator that they harbor it. Natural satellites are expected to outnumber planets by a large margin and the study of their habitability is therefore important to astrobiology and the search for extraterrestrial life. There are, nevertheless, significant environmental variables specific to moons.
In astronomy, a regular moon or a regular satellite is a natural satellite following a relatively close, stable, and circular orbit which is generally aligned to its primary's equator. They form within discs of debris and gas that once surrounded their primary, usually the aftermath of a large collision or leftover material accumulated from the protoplanetary disc. Young regular moons then begin to accumulate material within the circumplanetary disc in a process similar to planetary accretion, as opposed to irregular moons, which formed independently before being captured into orbit around the primary.
A planetary-mass moon is a planetary-mass object that is also a natural satellite. They are large and ellipsoidal in shape. Moons may be in hydrostatic equilibrium due to tidal or radiogenic heating, in some cases forming a subsurface ocean. Two moons in the Solar System, Ganymede and Titan, are larger than the planet Mercury, and a third, Callisto, is just slightly smaller than it, although all three are less massive. Additionally, seven – Ganymede, Titan, Callisto, Io, Earth's Moon, Europa, and Triton – are larger and more massive than the dwarf planets Pluto and Eris.
An ice planet or icy planet is a type of planet with an icy surface of volatiles such as water, ammonia, and methane. Ice planets consist of a global cryosphere.
A planetary surface is where the solid or liquid material of certain types of astronomical objects contacts the atmosphere or outer space. Planetary surfaces are found on solid objects of planetary mass, including terrestrial planets, dwarf planets, natural satellites, planetesimals and many other small Solar System bodies (SSSBs). The study of planetary surfaces is a field of planetary geology known as surface geology, but also a focus on a number of fields including planetary cartography, topography, geomorphology, atmospheric sciences, and astronomy. Land is the term given to non-liquid planetary surfaces. The term landing is used to describe the collision of an object with a planetary surface and is usually at a velocity in which the object can remain intact and remain attached.
Planetary oceanography, also called astro-oceanography or exo-oceanography, is the study of oceans on planets and moons other than Earth. Unlike other planetary sciences like astrobiology, astrochemistry, and planetary geology, it only began after the discovery of underground oceans in Saturn's moon Titan and Jupiter's moon Europa. This field remains speculative until further missions reach the oceans beneath the rock or ice layer of the moons. There are many theories about oceans or even ocean worlds of celestial bodies in the Solar System, from oceans made of diamond in Neptune to a gigantic ocean of liquid hydrogen that may exist underneath Jupiter's surface.
Journey to Enceladus and Titan (JET) is an astrobiology mission concept to assess the habitability potential of Enceladus and Titan, moons of Saturn.
The Ocean Worlds Exploration Program (OWEP) is a NASA program to explore ocean worlds in the outer Solar System that could possess subsurface oceans to assess their habitability and to seek biosignatures of simple extraterrestrial life.
Planetary habitability in the Solar System is the study that searches the possible existence of past or present extraterrestrial life in those celestial bodies. As exoplanets are too far away and can only be studied by indirect means, the celestial bodies in the Solar System allow for a much more detailed study: direct telescope observation, space probes, rovers and even human spaceflight.