The NASA/ESA Hubble Space Telescope has imaged what may be water vapor plumes erupting off the surface of Europa, the sixth-closest moon of Jupiter and the smallest of its four Galilean satellites. The surface of Europa looms large in this newly-reprocessed color view; image scale is 1.6 km per pixel; north on Europa is at right. Image credit: NASA / JPL-Caltech / SETI Institute. Europa has a global ocean containing twice as much water as Earth’s...