Scientists from the University of Texas at Austin have discovered what appears to be a massive body of liquid water locked inside the icy shell of Jupiter's moon Europa.
Britney Schmidt, a postdoctoral fellow at The University of Texas at Austin's Institute for Geophysics, believes the water could represent a potential habitat for life, with many more such lakes possibly existing throughout the shallow regions of Europa's shell.
Further increasing the potential for life, the newly discovered lake is 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 inferred to exist below the thick ice shell.
"One opinion in the scientific community has been, 'If the ice shell is thick, that's bad for biology - that it might mean the surface isn't communicating with the underlying ocean,'" Schmidt explained.
"Now we see evidence that even though the ice shell is thick, it can mix vigorously. That could make Europa and its ocean more habitable."
Scientists focused on Galileo spacecraft images of two roughly circular, bumpy features on Europa's surface known as chaos terrains. Based on similar processes seen here on Earth - on ice shelves and under glaciers overlaying volcanoes - the researchers developed a four-step model to explain how the features form on Europa. It resolves several conflicting observations, some of which seemed to suggest that the ice shell is thick and others that it is thin.
"I read the [University of Austin] paper and immediately thought, yes, that's it, that makes sense," said Robert Pappalardo, senior research scientist at NASA's Planetary Science Section. "It's the only convincing model that fits the full range of observations. To me, that says yes, that's the right answer."
The scientists have good reason to believe their model is correct, based on observations of Europa from the Galileo spacecraft and of Earth. Still, because the inferred lakes are several kilometers below the surface, the only true confirmation of their presence would come from a future spacecraft mission designed to probe the ice shell itself.
Such a mission was rated as the second-highest priority flagship mission by the National Research Council's recent Planetary Science Decadal Survey and is currently being studied by NASA.