The huge geysers on Jupiter's icy moon Europa have gone underground.
Late last year, scientists announced that NASA's Hubble Space Telescope had detected plumes of water vapor spewing about 120 miles (200 kilometers) into space from Europa's south pole in December 2012. The news was met with a great deal of excitement, as it suggested that a robotic probe may be able to sample Europa's possibly life-supporting subsurface ocean without touching down.
The researchers have trained Hubble on Europa repeatedly since then, trying to confirm and characterize the plumes during observations in January, February, November and December of this year. But they've come up empty. [Photos: Europa, Mysterious Icy Moon of Jupiter]
"We have not yet found any signals of waper vapor in the new images so far," team member Lorenz Roth, of the Southwest Research Institute in San Antonio, said Dec. 19 during a talk here at the annual fall meeting of the American Geophysical Union (AGU).
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