Results from the Cassini spaceprobe, currently exploring Saturn and its 60-plus moons, indicate that the moon Enceladus could be a home for life, as there may be water trapped under its frozen surface. Cassini shows that geyser-like plumes (middle picture) erupt from ‘tiger stripe’ fractures (bottom) across the moon's south pole, and seem to come from an underground ocean or deep caverns.
The water could be salty, like the Earth's oceans, and not too acidic for life. Importantly, Cassini has also detected organic chemicals, results that suggest there’s a possibility of life down there.
Cassini first saw the plumes in 2005, when scientists thought they were probably violent gushers; today it seems more likely that they are steady vapour jets, caused by water leaking through the icy surface. Commenting in the magazine Nature US planetary scientist Dr John Spencer has suggested a picture of Enceladus that includes: “...the possibility of misty ice caverns floored with pools and channels of salty water, lurking beneath the tiger stripes. What else may lurk in those salty pools, if they exist, remains to be seen."
Cassini will make two more flybys of Enceladus in November this year.
Cassini information is here, and Nature magazine is here, though much of the information is for subscribers only.
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