SA’s Hubble Space Telescope has the best evidence yet for an underground saltwater ocean on Ganymede, Jupiter’s largest moon. The subterranean ocean is thought to have more water than all the water on Earth’s surface.
Identifying liquid water is crucial in the search for habitable worlds beyond Earth and for the search for life, as we know it.
“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. “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.”
Okay, but here is a question: What if it turns out that Ganymede’s water is sterile?
Does that count in discussions about life on exoplanets? Why or why not?
See also: Don’t let Mars fool you. Those exoplanets teem with life!