Ocean planet

Illustration of a hypothetical ocean planet with a terrestrial atmosphere and two satellites

An ocean planet is a hypothetical type of planet whose surface is completely covered with an ocean of water.

Planetary objects that form in the outer solar system begin as a comet-like mixture of roughly 50% water and 50% rock by weight. Simulations of solar system formation have shown that planets are likely to migrate inward or outward as they form, presenting the possibility that icy planets could move to orbits where their ice melts into liquid form, turning them into ocean planets. This possibility was first discussed in the professional astronomical literature by Marc Kuchner ^[1] and Alain Léger^[2] in 2003. Such planets could theoretically support life.

The oceans on such planets could be hundreds of kilometers deep, much deeper than the oceans of Earth. The immense pressures in the lower regions of these oceans could lead to the formation of a mantle of exotic forms of ice. This ice would not necessarily be as cold as conventional ice. If the planet is close enough to its sun that the water's temperature reaches the boiling point, the water will become supercritical and lack a well-defined surface.^[2]

The extrasolar planet GJ 1214 b is currently the most likely candidate for an ocean planet, with data-fitting mass and radius values that are consistent with a modeled composition of 75% H₂O (and 22% Si, 3% Fe).^[3][4]

Fictional ocean planets

Fictional ocean planets have been used as story motifs:

• C.S. Lewis's novel Perelandra takes place on a water covered world of the same name, representing a concept of Venus not uncommon in fiction of the time.
• The novel Solaris (1961) by Stanislaw Lem revolves around an ocean planet which is in truth a single, ocean-sized organism.^[5]
• Monea, the television series Star Trek: Voyager episode "Thirty Days"^[6]
• Kamino, in the film series "Star Wars Episode II: Attack of the Clones"^[6]
• Manaan, in the game Star Wars: Knights of the Old Republic
• The ocean world Kainui, which, along with its twin uninhabited ocean planet, Kaihapa, circles a binary star system, in the novel "Noise" by Hal Clement. Kainui's Maori-descended colonists live a nomadic existence, traveling about by boat or on one of the planet's anchorless floating cities.^[6]
• An ocean planet is the setting for the novel The Blue World by Jack Vance.

References

External links

• Selsis, F.; B. Chazelas, P. Borde, M. Ollivier, F. Brachet, M. Decaudin, F. Bouchy, D. Ehrenreich, J.-M. Griessmeier, H. Lammer, C. Sotin, O. Grasset, C. Moutou, P. Barge, M. Deleuil, D. Mawet, D. Despois, J. F. Kasting, A. Leger (2007). "Could we identify hot Ocean-Planets with CoRoT, Kepler and Doppler velocimetry?". Icarus 191: 453. doi:10.1016/j.icarus.2007.04.010. arΧiv:astro-ph/0701608. http://xxx.arxiv.org/abs/astro-ph/0701608. 

v • d • e Exoplanets Classes Carbon planet • Chthonian planet • Circumbinary planet • Cold Jupiter • Cold Neptune • Desert planet • Eccentric Jupiter • Goldilocks planet • Hot Jupiter • Hot Neptune • Jovian planet • Ocean planet • Pulsar planet • Super-Earth • Terrestrial planet Systems Binary star • Hypothetical extrasolar planet • Interstellar planet • Planetary system • Extrasolar moon Missions COROT • Kepler Mission • PEGASE • Space Interferometry Mission • New Worlds Mission • Terrestrial Planet Finder • Darwin (ESA) See also: Stars with extrasolar planets • Extrasolar planet extremes • Unconfirmed exoplanets