Alien life in our own neighborhood.
It's an exciting possibility that we might reveal as fact on multiple planetary bodies like Mars. But scientists think Jupiter's moon Europa could also be a major potential breeding ground for extraterrestrial life. Its deep saltwater ocean intrigues, though its thick icy outer shell — which is a dizzying 12 to 19 miles (20 to 30 km) thick, could become a barrier for future sampling missions.
But now, a new study published in the journal Nature Communications provides evidence that the icy shell may be less obstructive than we thought.
And this means that, instead of digging through the ice shell of the frigid moon, forthcoming missions to Europa might confirm water — and possibly signs of alien life itself — inside of the shells, in shallow bodies of liquid water, hiding right before our eyes.
"We identified [a] shallow water pocket in Greenland using ice-penetrating radar," lead study author Riley Culberg, a doctoral student in electrical engineering at Stanford and lead study author, told IE in an interview. "So it’s exciting that the Europa Clipper mission will also have an ice-penetrating radar instrument that can conduct similar imaging of the interior structure of Europa's ice shell."
Greenland's icy surface hints at liquid water on Europa
By comparing Europa's surface with ice-penetrating radar observations taken over Greenland, the researchers believe they have provided a whole new perspective on the theory of Europan life, showing how ice ridges might facilitate the exchange of nutrients from the moon's subsurface ocean.
The researchers based their new study on ice-penetrating radar observations that captured the formation of a "double ridge" feature in Greenland, showing many water pockets that may exist on similar features on the surface of Europa.
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"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," the study's senior author Dustin Schroeder, who's also an associate professor of geophysics at Stanford University’s School of Earth, Energy & Environmental Sciences, explained in a press statement shared with IE under embargo.
'Double ridge' features on Greenland could happen on alien worlds
"If the mechanism we see in Greenland is how these things happen on Europa, it suggests there's water everywhere," Schroeder continued. Since formations on the icy moon are so similar to those seen on the surface of Greenland's ice sheet, the scientists suspect they lend greater insight into the conditions on the Jovian moon.
Specifically, they found that an "M"-shaped crest in Greenland known as a double ridge could be a miniature version of a very large feature found on Europa. Double ridges on Europa can have crests measuring nearly 1,000 feet tall and are separated by valleys roughly half a mile wide.
This complex surface structure would be much more conducive to life than previous theories would suggest. "When we’re thinking about what the structure or dynamics of the ice shell tell us about habitability on Europa, it's really in terms of trying to understand whether the moon has the necessary combination of building blocks and conditions to sustain simple microorganisms," Culberg told IE over email.
"The potential for chemical cycling between the surface and ocean is likely to be [an] important factor, and the presence of shallow water would support the idea the idea of a fairly dynamic ice shell where that kind of exchange is possible," Culberg added, in the interview.
Searching for extraterrestrial life
The Stanford team's work draws primarily from surface elevation and ice-penetrating radar data that suggests Greenland's double ridge was formed when ice fractured around a pocket of pressurized liquid water, causing two peaks to form on either side.
"In Greenland, this double ridge formed in a place where water from surface lakes and streams frequently drains into the near-surface and refreezes," said Culberg, in the release. "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."
The researchers believe these dynamic surface processes support the theory of habitable conditions on Europa as they facilitate the exchange of nutrients between the subsurface ocean and the neighboring moons. By 2030, NASA's Europa Clipper spacecraft will be orbiting the moon, providing new insight based on this theory, and numerous others. While NASA's James Webb Space Telescope gears up to search for extraterrestrial life in distant solar systems this year, our nearby neighbor Europa may hold the key to discovering the first living organisms on a nearby celestial neighbor.