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\n Plumes of ice particles, water vapour and organic molecules spray from Enceladus\u2019s south polar region<\/p>\n NASA\/JPL-Caltech<\/p>\n<\/div>\n<\/figcaption><\/figure>\n<\/p>\n The liquid water ocean hidden underneath the icy crust of Enceladus has long made this moon of Saturn one of the best prospects in the hunt for extraterrestrial life \u2013 and it just got even more promising. The discovery of heat emanating from the frozen moon\u2019s north pole hints the ocean is stable over geological timescales, giving life time to develop there.<\/p>\n \u201cFor the first time we can say with certainty that Enceladus is in a stable state, and that has big implications for habitability,\u201d says Carly Howett at the University of Oxford. \u201cWe knew that it had liquid water, all sorts of organic molecules, heat, but the stability was really the final piece of the puzzle.\u201d<\/p>\n Howett and her colleagues used data from NASA\u2019s Cassini spacecraft, which orbited Saturn from 2004 to 2017, to hunt for heat seeping out of Enceladus. Its interior is heated by tidal forces as it is stretched and crunched by Saturn\u2019s gravity, but so far this heat has only been caught leaking out of the south polar regions.<\/p>\n For life to have developed in Enceladus\u2019s ocean, it would require balance: the ocean should be putting out as much heat as is being put in. Measurements of the heat coming out of the south pole don\u2019t account for all of the heat input, but Howett and her team found the north pole is about 7 degrees warmer than we previously thought. Combined with the heat radiating from the south pole, that matches the total almost exactly \u2013 the ice shell is thicker around the equator, so heat only escapes in significant amounts at the poles.<\/p>\n <\/p>\n This means the ocean should be stable over long periods of time. \u201cIt\u2019s really hard to put a number on it, but we don\u2019t think it\u2019s going to freeze out any time soon, or that it\u2019s been frozen out any time recently,\u201d says Howett. \u201cWe know life needs time to evolve, and now we can say that it does have that stability.\u201d Actually finding that life, if it is there, is another story entirely. But both NASA and ESA have missions in the works to look for it over the coming decades.<\/p>\n Topics:<\/p>\n<\/section><\/div>\n