Europa’s Icy Shell May Be Habitable for Life

One of Jupiter’s many moons, Europa has captivated astronomers and astrobiologists for decades after evidence was collected in the 1970s suggesting that it had a subsurface ocean. An icy shell that is miles thick covers the possible ocean, but new evidence suggests that the ice may also have shallow pockets of liquid water, reports Michelle Star for Science Alert.

A recent study of Earth's Greenland ice sheet published this month in Nature Communications suggests that water may close to the surface of Jupiter's moon. Researchers analyzed two ridges on Greenland's ice sheet with ice-penetrating radar, and found that the ridges look like those on the far away Jovian moon, per the Independent’s Jon Kelvey. The evidence suggests that the ridges on Europa’s icy shell may form above pockets of water that may be habitable for life, a statement explains. 

“Because it’s closer to the surface, where you get interesting chemicals from space, other moons, and the volcanoes of Io, there’s a possibility that life has a shot if there are pockets of water in the shell,” says study author Dustin Schroeder, a geophysics expert at Stanford University in a statement. “If the mechanism we see in Greenland is how these things happen on Europa, it suggests there’s water everywhere.”

First spotted by Galileo Galilei in 1610, Europa is 2,000 miles wide and slightly smaller than Earth’s moon. The Jovian moon became an interest to researchers as a place that potentially could harbor life after observations from Earth-bound telescopes and space probes found evidence of an ocean 10 to 15 miles beneath the icy surface, reports Ian Sample for the Guardian. The moon’s ocean is estimated to be 40 to 100 miles deep and may hold twice as much water as Earth’s oceans combined.

In Greenland, the double ridges of ice are uncommon. But on Europa, the features are abundant. The hills on the Europa appear as dramatic scars, and astronomers have been wondering how they formed since the Galileo space probe first imaged the features in the 1990s; however, Greenland may bring scientists closer to the answer, per Science Alert.

In Greenland, the ridges formed when shallow pools of subsurface water froze, thawed and refroze, fracturing the surface over time, the Guardian reports. Those shallow underground pools formed when water drained from surface lakes. On Europa, the team suspects that the water is pushed up through the icy shell via cracks. 

“One way that similar shallow water pockets could form on Europa might be through water from the subsurface ocean being forced up into the ice shell through fractures – and that would suggest there could be a reasonable amount of exchange happening inside of the ice shell,” says Riley Culberg, study lead author and electrical engineer at Stanford, in a statement. 

Researchers will get a chance to study the surface of Europa further and compare data to data from Greenland after NASA’s Europa Clipper and the European Space Agency’s JUICE probe arrive to study the moon in the coming years.

Elizabeth Gamillo | | READ MORE

Elizabeth Gamillo is a correspondent for Smithsonian and a science journalist based in Milwaukee, Wisconsin. She has written for Science magazine as their 2018 AAAS Diverse Voices in Science Journalism Intern.