This composite image shows suspicious jets of water vapor erupting at the 7 o'clock position outside the boundary of Jupiter's moon Europa. The streams, imaged by NASA's Hubble Space Telescope's Imaging Spectrometer camera, were seen in silhouette as the moon passed in front of Jupiter. The Hubble data were collected on January 26, 2014. The image of Europa superimposed on the Hubble data consists of data from the Galileo Voyager missions Credit: NASA/ESA/W. Sparks (STScI)/USGS Astrogeology Science Center

This composite image shows suspicious jets of water vapor erupting at the 7 o'clock position outside the boundary of Jupiter's moon Europa. The streams, imaged by NASA's Hubble Space Telescope's Imaging Spectrometer camera, were seen in silhouette as the moon passed in front of Jupiter. The Hubble data were collected on January 26, 2014. The image of Europa superimposed on the Hubble data consists of data from the Galileo Voyager missions Credit: NASA/ESA/W. Sparks (STScI)/USGS Astrogeology Science Center

This composite image shows suspicious jets of water vapor erupting at the 7 o'clock position outside the boundary of Jupiter's moon Europa. The streams, imaged by NASA's Hubble Space Telescope's Imaging Spectrometer camera, were seen in silhouette as the moon passed in front of Jupiter. The Hubble data were collected on January 26, 2014. The image of Europa superimposed on the Hubble data consists of data from the Galileo Voyager missions Credit: NASA/ESA/W. Sparks (STScI)/USGS Astrogeology Science Center