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Astronomy in the News

Mercury Winter 2012 Table of Contents


Artist's impression of the Great Lake on Europa

Artist's impression of the "Great Lake" on Jupiter's moon Europa. Scientists speculate many more exist throughout the shallow regions of the moon's icy shell. Courtesy Britney Schmidt / Dead Pixel FX / U of Texas at Austin.

Evidence for Subsurface 'Great Lake' on Europa

Johns Hopkins University Applied Physics Laboratory

In a finding of significance in the search for life beyond Earth, scientists have discovered what appears to be a body of liquid water the volume of the North American Great Lakes locked inside the icy shell of Jupiter's moon Europa — which could represent a new potential habitat for life.

Many more such lakes exist throughout the shallow regions of Europa's shell, the researchers predict in an online article for the journal Nature. Further increasing the potential for life, many of these lakes are covered by floating ice shelves that seem to be collapsing, providing a mechanism for transferring nutrients and energy between the surface and a vast ocean already thought to exist below the thick ice shell.

The scientists focused on Galileo spacecraft images of two roughly circular, bumpy features on Europa's surface called chaos terrains. Based on similar processes seen here on Earth — on ice shelves and under glaciers overlaying volcanoes — they developed a four-step model to explain how the features form on Europa.

While one of the chaos terrains appears to be fully formed, the other might still be forming — an indication that Europa's surface is still geologically active. "For quite some time, Europa geologists have been struggling figure out what these features are and how they form," says APL's Louise Prockter, a senior planetary scientist who has conducted numerous studies of Europa. "This is the first time that anyone has come up with an end-to-end model that explains what we see on the surface."

"If we're ever to send a landed mission to Europa, these areas would be great places to study," Prockter says.


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