This graphic shows the location of water vapor detected over Europa's south pole that provides the first strong evidence of water plumes erupting off Europa's surface, in observations taken by NASA's Hubble Space Telescope in December 2012.
Hubble didn't photograph plumes, but spectroscopically detected auroral emissions from oxygen and hydrogen. The aurora is powered by Jupiter's magnetic field.
This is only the second moon in the solar system found ejecting water vapor from the frigid surface. The image of Europa is derived from a global surface map generated from combined NASA Voyager and Galileo space probe observations.