Finding liquid water is an important first step to identifying inhabitable worlds outside the planet Earth, according to a joint press release from the Space Telescope Science Institute in Baltimore, Md. and NASA Headquarters in Washington, D.C.
"This discovery marks a significant milestone, highlighting what only Hubble can accomplish," said John Grunsfeld, assistant administrator of NASA's Science Mission Directorate at NASA Headquarters, Washington, D.C., according to the press release. "In its 25 years in orbit, Hubble has made many scientific discoveries in our own solar system. A deep ocean under the icy crust of Ganymede opens up further exciting possibilities for life beyond Earth."
Ganymede has some unique qualities. Not only is it the largest moon in our solar system, but it is the only moon with its own magnetic field that causes aurorae - hot electrified gas that glow in ribbons circling the moon's poles. Due to its proximity to Jupiter, Ganymede is held by Jupiter's magnetic field. When a change in Jupiter's magnetic field occurs, the aurorae change and appear to rock back and forth.
The new observations were done in ultraviolet light and could only be accomplished with a space telescope high above Earth's atmosphere, which blocks most ultraviolet light, such as the Hubble.
The team's results are published online in the Journal of Geophysical Research: Space Physics.
Hubble is a project shared by NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Md., manages Hubble. The Space Telescope Science Institute (STScI) in Baltimore, Md., conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.
