A new study says that Greenland’s ice sheets are very similar to the landscape of a faraway planet. This could make it more likely that we will find extraterrestrials.
Europa, Jupiter’s moon, has long been thought to be a good candidate for alien microbes since it appears to have a liquid saltwater ocean that could be 150 kilometers deep.
The ocean, which is supposed to span the entire moon, is surrounded in a shell of ice that is up to 30 kilometers thick.
According to a new study, this solid, frozen crust represents a potentially livable region in and of itself.
The creation of Greenland’s double ridge was driven by the refreezing of liquid subsurface water, according to radar data. If Europa’s characteristics are formed in the same way, it could indicate the presence of large amounts of liquid water — a necessary component of life – near the surface of the Jovian moon’s thick ice shell.
Europa has received attention in the quest for extraterrestrial life as one of the locations in our solar system that may be habitable, maybe by bacteria, due to a vast saltwater ocean discovered deep beneath its ice crust. Numerous water pockets near the surface would provide a second possible habitat for life.
“The presence of liquid water in the ice shell would suggest that exchange between the ocean and ice shell is common, which could be important for chemical cycling that would help support life,” explained Stanford University geophysicist Riley Culberg, lead author of the study. “Shallow water in particular also means there might be easier targets for future space missions to image or sample that could at least preserve evidence of life without having to fully access the deep ocean.”
NASA’s robotic Europa Clipper spacecraft is set to launch in 2024, with the goal of learning more about whether this moon is habitable.
The short depth of Europa’s putative water pockets – possibly within six-tenths of a kilometer of the surface – would also put them close to chemicals necessary for the creation of any life that might exist on the planet’s surface.
Europa is the fourth-largest of Jupiter’s 79 known moons, with a diameter of 1,940 miles (3,100 kilometers), somewhat smaller than Earth’s moon but larger than the dwarf planet Pluto. The oceans on Europa may hold twice as much water as those on Earth. Marine bacteria were the first life forms on Earth.
Europa’s double ridges, which can stretch for hundreds of kilometers (km), are usually roughly 490-650 feet (150-200 meters) height, with the peaks spaced around three to six tenths of a mile (0.5-1 km) apart.
Scientists have argued how they formed. Culberg was intrigued by their likeness to a landform he was familiar with from northwestern Greenland, with peaks approximately 6.5 feet (2 metres) tall, spaced by about 160 feet (50 metres), and spanning about a half mile (800 metres).
“The Greenland double ridge feature formed from the successive refreezing, pressurization and fracture of a near-surface water pocket. We see two ridges, rather than one, because the shallow water pocket was also split in two by a fracture filled with refrozen water,” Culberg added.
The water pocket in Greenland was about 50 feet (15 meters) below the surface, roughly a mile (1.6 km) broad, and about 33 feet (10 meters) thick.
Each connected water pocket may have a volume comparable to Lake Erie, one of North America’s Great Lakes, if Europa’s multiple double ridges were formed by the same method.
“Between having two potential habitats and the fact that double ridges – and the near-surface water bodies they may imply – are among the most common features on Europa’s surface, it makes this moon a very exciting candidate for habitability indeed,” Stanford geophysics professor and study co-author Dustin Schroeder added.
Image Credit: JUSTICE BLAINE WAINWRIGHT
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