Tidal heating Tidal heating (also known as tidal working or tidal flexing) occurs through the tidal friction processes: orbital and rotational energy is dissipated as heat in either (or both) the surface ocean or interior of a planet or satellite. When an object ...

of Io (also known as tidal working) occurs through the tidal friction processes between

Jupiter Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but ...

and its moon. Orbital and rotational energy are dissipated as heat in the crust of the moon. Io has a similar mass and size as 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 ...

, but Io is the most geologically active body 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 ...

. This is caused by the heating mechanism of Io. The major heating source of Earth and its moon is radioactive heating, but the heating source on Io is

tidal heating Tidal heating (also known as tidal working or tidal flexing) occurs through the tidal friction processes: orbital and rotational energy is dissipated as heat in either (or both) the surface ocean or interior of a planet or satellite. When an object ...

. As Jupiter is very massive, the side of Io nearest to Jupiter has a slightly larger gravitational pull than the opposite side. This difference in gravitational forces cause distortion of Io’s shape. Differently from the Earth’s only moon, Jupiter has two other large moons (

Europa Europa may refer to: Places * Europe * Europa (Roman province), a province within the Diocese of Thrace * Europa (Seville Metro), Seville, Spain; a station on the Seville Metro * Europa City, Paris, France; a planned development * Europa Cliff ...

and Ganymede) that are in an

orbital resonance In celestial mechanics, orbital resonance occurs when orbiting bodies exert regular, periodic gravitational influence on each other, usually because their orbital periods are related by a ratio of small integers. Most commonly, this relationsh ...

with it. Io is the innermost of this set of resonant moons, and their interactions maintain its orbit in an

eccentric Eccentricity or eccentric may refer to: * Eccentricity (behavior), odd behavior on the part of a person, as opposed to being "normal" Mathematics, science and technology Mathematics * Off-center, in geometry * Eccentricity (graph theory) of a v ...

(elliptical) state. The varying distance between Jupiter and Io continually changes the degree of distortion of Io's shape and flexes its interior, frictionally heating it. The friction-induced heating drives strong volcanic activities on the surface of Io. Although there is general agreement that the cause of the heat as manifested in Io's many volcanoes is tidal heating from the pull of gravity from Jupiter and its moon Europa, the volcanoes are not in the positions predicted with tidal heating. They are shifted 30 to 60 degrees to the East. A study published in 2015, explains the eastern shift by an ocean of molten rock under the surface. The movement of this magma would generate extra heat. Liquids, especially if they are sticky (or viscous), can produce heat through friction. The team who wrote the paper believe that the subsurface ocean is a mixture of molten and solid rock. When the molten rock flows, it may swirl and rub against the surrounding rock, thus generating heat. Other moons in the Solar System undergo tidal heating, and they too may have more heat generated by this process, including heat from the movement of water. This ability to generate heat in a subsurface ocean increases the chance of life on bodies like

and

Enceladus Enceladus is the sixth-largest moon of Saturn (19th largest in the Solar System). It is about in diameter, about a tenth of that of Saturn's largest moon, Titan. Enceladus is mostly covered by fresh, clean ice, making it one of the most refl ...

References

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External links

Tidal Heating tutorial
Io (moon)