Scientists have known for about a decade that Jupiter's moon Europa has a giant salt-water ocean lying beneath a crust of ice, a crust so thick that it would make the chances of life existing below very slim. But a new study based on data from NASA's Galileo spacecraft posits that there may be lakes of liquid water within the crust (as rendered by an artist in the image above). The study appeared in the journal Nature last week.

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Image: University of Texas at Austin.