STANFORD, Calif. — Alien life may be a lot closer to Earth than anyone thinks! A new study exploring the icy shell of Europa, one of Jupiter’s largest moons, finds the frigid satellite shares striking similarities with Greenland, which is home to its own unique aquatic life.
Researchers at Stanford believe life could have evolved in the moon’s shallow pockets of water near the surface. The findings come from an analysis of symmetrical landforms called double ridges. They stretch for hundreds of miles across the surface of Europa, flanking a shallow trough.
Ice-penetrating radar observations captured the formation of the same type of geometrical feature in northwest Greenland. It is compelling evidence of potentially habitable environments within the exterior of the Jovian satellite.
“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 senior author Professor Dustin Schroeder in a university release. “If the mechanism we see in Greenland is how these things happen on Europa, it suggests there’s water everywhere.”
Finding aliens by accident?
Oddly enough, the study authors weren’t actually searching for signs of life near Jupiter. Prof. Schroeder is an expert on global warming, rather than extraterrestrials.
“We were working on something totally different related to climate change and its impact on the surface of Greenland when we saw these tiny double ridges – and we were able to see the ridges go from ‘not formed’ to ‘formed,’” Schroeder explains.
Upon further examination, they identified a miniature version of the most prominent features on Europa – which is mostly flat. Prof. Schroeder described them as “dramatic gashes,” reaching nearly 1,000 feet and separated by valleys about half a mile wide.
The Galileo spacecraft first photographed the formations in the 1990s. However, an explanation of how they formed has remained a mystery – until now. The study in Nature Communications used data collected from 2015 to 2017 by NASA’s Operation IceBridge which monitors Earth’s polar ice.
It revealed Greenland’s double ridge formed when ice fractured around a pocket of pressurized water that was refreezing inside. This caused two peaks to rise into the distinct shape.
“In Greenland, this double ridge formed in a place where water from surface lakes and streams frequently drains into the near-surface and refreezes,” says lead study author Riley Culberg, a PhD student in electrical engineering at Stanford.
“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.”
An alien world just like Greenland?
Rather than behaving like a block of inert ice, the moon’s shell seems to undergo a variety of geological and hydrological processes. The theory is supported by this study and others – including evidence of water plumes that erupt to the surface.
A dynamic ice shell, which is about 60 miles thick, could support habitability since it facilitates the exchange between the subsurface ocean and nutrients from neighboring celestial bodies building up on the surface.
“People have been studying these double ridges for over 20 years now, but this is the first time we were actually able to watch something similar on Earth and see nature work out its magic,” says study co-author Gregor Steinbrügge, a planetary scientist at NASA’s Jet Propulsion Laboratory (JPL). “We are making a much bigger step into the direction of understanding what processes actually dominate the physics and the dynamics of Europa’s ice shell.”
The moon harbors a deep salty ocean beneath the ice, which has long captivated the imagination of astronomers looking for alien life.
“The mechanism we put forward in this paper would have been almost too audacious and complicated to propose without seeing it happen in Greenland,” Schroeder adds.
The findings give researchers a unique radar signature for quickly detecting double ridge formations, which scientists are planning to use during future explorations of Europa from space.
“We are another hypothesis on top of many – we just have the advantage that our hypothesis has some observations from the formation of a similar feature on Earth to back it up,” Culberg explains. “It’s opening up all these new possibilities for a very exciting discovery.”
Could UV light reveal life on Jupiter’s moon?
Millions of ancient microbes have been discovered 3,000 meters deep in Greenland’s glaciers, suggesting hardy species may live in ice elsewhere in the solar system. That ice may be just as fertile as Earth’s oceans. Scientists have even found bacteria buried deep beneath the Antarctic ice sheet.
Scientists have long been intrigued by the possibility of finding extraterrestrial life forms in ice-covered worlds far from Earth, especially on Europa. The ice surface of Europa is streaked with reddish-brown cracks, possibly caused by micro-organisms suspended in the ice.
Minerals from the rocky interior are seeping through cracks in the ice, getting blasted by UV radiation from the Sun — creating Europa’s blushing red surface. That same UV radiation can break apart water molecules, allowing oxygen to sink back down into the ocean. They are just the kinds of ingredients life needs to get started in a watery environment.
South West News Service writer Mark Waghorn contributed to this report.