Researchers at Stanford University have found that subsurface saline ponds on Jupiter's moon Europa could be promising places to search for signs of life beyond Earth. Scientists observed that the giant parallel ridges extending for hundreds of miles on Europa bear a striking resemblance to surface features discovered on Greenland's ice sheet. Dustin Schroeder, an assistant professor of geophysics at Stanford, stated, "Liquid water near the surface of the ice shell is really a promising place to imagine life existing."
Also, physicist Riley Kohlberg noted, "There are small double ridges on the ice sheet in Greenland that look exactly like those we see on the surface of Jupiter's moon Europa." Researchers described in the journal Nature Communications how these double ice ridges in Greenland, which are about 50 times smaller than those on Europa, formed when shallow subsurface water froze and the surface broke repeatedly, leading to the gradual rise of the double ridges.
Water drains into the subsurface pockets from surface lakes in Greenland; however, on Europa, scientists suspect that liquid water is pushed toward the surface from the underlying ocean through fractures in the ice shell. This movement of water could help circulate the necessary chemicals for life at the bottom of Europa's ocean, allowing the ridges on Jupiter's moon to form due to upward pressure from the water.
Europa is 2,000 miles wide, slightly smaller than Earth's moon, and has become a favored location for scientists seeking to find life in space, especially after telescopes and passing spacecraft provided evidence of an ocean lying 10 to 15 miles beneath its icy surface.
