Kraken Mare is the largest known body of liquid on the surface of

Saturn 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; h ...

's moon Titan. It was discovered by the space probe '' Cassini'' in 2006, and was named in 2008 after the

Kraken The kraken () is a legendary sea monster of enormous size said to appear off the coasts of Norway. Kraken, the subject of sailors' superstitions and mythos, was first described in the modern age at the turn of the 18th century, in a travelogu ...

, a legendary

sea monster Sea monsters are beings from folklore believed to dwell in the sea and often imagined to be of immense size. Marine monsters can take many forms, including sea dragons, sea serpents, or tentacled beasts. They can be slimy and scaly and are ofte ...

. It covers an area slightly bigger than the

Caspian Sea The Caspian Sea is the world's largest inland body of water, often described as the world's largest lake or a full-fledged sea. An endorheic basin, it lies between Europe and Asia; east of the Caucasus, west of the broad steppe of Central Asia ...

on Earth, making it the largest known lake in the

Solar System The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar S ...

Description

At 500,000 km², Kraken Mare is thought to be the largest body of liquid on Titan. It lies in the moon's northern polar region. Its status as a sea of

hydrocarbon In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ex ...

s (mainly liquid

methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Eart ...

) was identified by radar imagery. Kraken Mare is thought to be larger than the

on Earth. Analyses of the Cassini radar altimeter data used as a sounder have shown that the main body of Kraken Mare is at least 100 m deep and likely deeper than 300 m. One of its northernmost bays (Moray Sinus) has a depth of 85 (−18, +28) m at its center and shows an attenuation of the signal in the liquid that is compatible with a composition of 70% methane, 16% nitrogen and 14% ethane (assuming ideal mixing). Shallow

capillary waves A capillary wave is a wave traveling along the phase boundary of a fluid, whose dynamics and phase velocity are dominated by the effects of surface tension. Capillary waves are common in nature, and are often referred to as ripples. The wav ...

1.5 centimeters high moving at 0.7 meters per second have been detected on the surface of Kraken Mare. An island in the sea is named

Mayda Insula Mayda Insula is an island in the Kraken Mare, a body of liquid composed primarily of methane, on Saturn's largest moon Titan. Mayda Insula is the first island (insula) to be named on a planet or moon other than Earth. Discovery and naming Mayda ...

. Kraken Mare may be

hydrologically Hydrology () is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water resources, and environmental watershed sustainability. A practitioner of hydrology is call ...

connected to the second-largest sea on Titan,

Ligeia Mare Ligeia Mare is a lake in the north polar region of Titan, the planet Saturn's largest moon. It is the second largest body of liquid on the surface of Titan, after Kraken Mare. Larger than Lake Superior on Earth, it is mostly composed of liquid ...

. This connection has been suggested for the difference in sea composition, as certain compounds flow into Kraken Mare from Ligeia Mare. In addition, Kraken Mare has a lower methane concentration than Ligeia Mare. The narrow constriction in the sea at 317°W, 67°N, about 17 km wide and similar in size to the

Strait of Gibraltar The Strait of Gibraltar ( ar, مضيق جبل طارق, Maḍīq Jabal Ṭāriq; es, Estrecho de Gibraltar, Archaic: Pillars of Hercules), also known as the Straits of Gibraltar, is a narrow strait that connects the Atlantic Ocean to the Medi ...

, officially named Seldon Fretum, has been termed the 'Throat of Kraken' and suggested to be a location of significant currents. Titan's

orbital eccentricity In astrodynamics, the orbital eccentricity of an astronomical object is a dimensionless parameter that determines the amount by which its orbit around another body deviates from a perfect circle. A value of 0 is a circular orbit, values betwee ...

may lead to tides of 1 m in Kraken Mare, generating currents here of 0.5 m/s and possibly

whirlpool A whirlpool is a body of rotating water produced by opposing currents or a current running into an obstacle. Small whirlpools form when a bath or a sink is draining. More powerful ones formed in seas or oceans may be called maelstroms ( ). ''Vo ...

s. Other calculations estimate tides as high as 5 meters. Changing features known as "Magic Islands" are observed in Kraken Mare. These features, which are further indication of an active hydrocarbon cycle on Titan, are possibly rising bubbles due to nitrogen

exsolution A solid solution, a term popularly used for metals, is a homogenous mixture of two different kinds of atoms in solid state and have a single crystal structure. Many examples can be found in metallurgy, geology, and solid-state chemistry. The wor ...

Observation and exploration

Kraken Mare, along with other

Lakes of Titan Lakes of ethane and methane on Titan, Saturn's largest moon, have been detected by the ''Cassini–Huygens'' space probe, and had been suspected long before. The large ones are known as maria (seas) and the small ones as lacūs (lakes). History ...

, was first discovered by the

Cassini–Huygens ''Cassini–Huygens'' ( ), commonly called ''Cassini'', was a space research, space-research mission by NASA, the European Space Agency (ESA), and the Italian Space Agency (ASI) to send a space probe to study the planet Saturn and its system, i ...

space probe on July 22, 2006. This was accomplished by noticing that certain dark regions, especially near the poles, had low radar reflectivity, as well as similar morphological features to that of terrestrial lakes. Many observations since have confirmed these findings. In addition to the radar images, the Cassini instrument VIMS (Visible and Infrared Mapping Spectrometer) has surveyed Kraken Mare and its surroundings. There have been multiple proposals and ideas to explore the depths of Kraken Mare via probes and submarines. One such submarine has gone through a phase one NASA study, complete with submarine design and schematics. Another proposal, the

Titan Mare Explorer Titan Mare Explorer (TiME) is a proposed design for a lander for Saturn's moon Titan. TiME is a relatively low-cost, outer-planet mission designed to measure the organic constituents on Titan and would have performed the first nautical exploratio ...

was a finalist to explore the lake

, with Kraken Mare as the secondary target, but

InSight Insight is the understanding of a specific cause and effect within a particular context. The term insight can have several related meanings: *a piece of information *the act or result of understanding the inner nature of things or of seeing intu ...

, a Mars lander, was accepted instead. The Titan Mare Explorer was also suggested to be included on the unprogressed

Titan Saturn System Mission Titan Saturn System Mission (TSSM) was a joint NASA–ESA proposal for an exploration of Saturn and its moons Titan (moon), Titan and Enceladus (moon), Enceladus, where many complex phenomena were revealed by ''Cassini–Huygens, Cassini''. TSSM ...

. While a mission to Titan has been approved, the drone

Dragonfly (spacecraft) ''Dragonfly'' is a planned spacecraft and NASA mission, which will send a robotic rotorcraft to the surface of Titan, the largest moon of Saturn. It would be the first aircraft on Titan and is intended to make the first powered and fully con ...

, there are no current missions to explore Kraken Mare or other lakes on Titan.

Gallery

Image:Kraken mare.jpg, Synthetic aperture radar image (top) overlaid onto a visible light/infrared image of Titan's north polar region, showing the full extent of Kraken Mare. Image:PIA09180 Kraken Mare.jpg, Radar image showing the northern portion of Kraken Mare, including the large island Mayda Insula. Image:PIA09211.jpg, Radar image of a portion of Kraken Mare with a rugged coastline and numerous islands. Image:PIA12481 Titan specular reflection.jpg,

Specular reflection Specular reflection, or regular reflection, is the mirror-like reflection of waves, such as light, from a surface. The law of reflection states that a reflected ray of light emerges from the reflecting surface at the same angle to the surf ...

off Jingpo Lacus in the Kraken Mare region, observed by ''Cassini'' on July 8, 2009.

Notes

References

External links

Labelled map of Titan's north polar region, based on radar imagery, showing lakes and seas
{{Titan Lakes of Titan (moon)