PelaCytherean Subtype

Hot Ocean Worlds

Pelavenusian (Whernside)
Image from Steve Bowers
Whernside, a hot water world
Hot ocean planets similar in size to Earth; 0.05 to 2.5 Earth masses

While these worlds retain a massive atmosphere rich in carbon dioxide and thus a heavy greenhouse effect, there is also such a large amount of water in the atmosphere and on the surface that a point is reached where a balance is maintained between the heat and pressure of the atmosphere, and the world-girdling ocean. Because the atmosphere is supercritical, it melds imperceptibly with the oceanic surface, and the upper levels of that ocean can be well in excess of 100 degrees Celsius.

However, deeper in the ocean temperatures can be of a more temperate nature, and at the oceanic floor the water may form high pressure ice depending on the temperature and salinity. Life may evolve here, even to the point of multicellular macroforms, typically clustered about geothermal hotspots, though many forms might eventually colonize the temperate mid-levels of the ocean.

Larger hot water worlds in the Superterrestrial range are known as pyrohydrothalassic worlds.
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Development Notes
Text by John M. Dollan and Steve Bowers
Initially published on 14 November 2008.