Europa’s similarity to Greenland hints that Jupiter moon could harbor life
6:00 JST, May 18, 2022
WASHINGTON (Reuters) — The uncanny resemblance between features on Europa’s frozen surface and a landform in Greenland that sits atop a sizable pocket of water are providing intriguing new indications that this moon of Jupiter may be capable of harboring life.
A study published last month explored similarities between elongated landforms called double ridges that look like huge gashes across Europa’s surface and a smaller version in Greenland examined using ice-penetrating radar.
Double ridges are linear, with two peaks and a central trough between them.
“If you sliced through one and looked at the cross section, it would look a bit like the capital letter ‘M,’” said Stanford University geophysicist Riley Culberg, lead author of the study published in the journal Nature Communications.
Radar data showed that refreezing of liquid subsurface water drove the formation of Greenland’s double ridge. If Europa’s features form the same way, this could signal the presence of copious amounts of liquid water — a key ingredient for life — near the surface of this Jovian moon’s thick outer ice shell.
In the search for extraterrestrial life, Europa has attracted attention as one of the locales in our solar system that may be habitable, perhaps by microbes, owing to a global saltwater ocean detected deep beneath its ice shell. Innumerable water pockets closer to the surface would represent a second potential habitat for organisms.
“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,” Culberg said. “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 scheduled for a 2024 launch to further investigate whether this moon possesses conditions suitable for life.
The shallow depth of Europa’s potential water pockets — perhaps within 1 kilometer of the surface — also would place them near chemicals vital for the formation of life that may exist on its surface.
With a diameter of 3,100 kilometers, Europa is the fourth-largest of Jupiter’s 79 known moons, a bit smaller than Earth’s moon but bigger than the dwarf planet Pluto. Europa’s ocean may contain double the water of those on Earth. Life first emerged on Earth as marine microbes.
Europa’s double ridges, sometimes extending hundreds kilometers, generally are around 150 to 200 meters tall, with the peaks about 0.5 to 1 kilometer apart.
Scientists have debated how they formed. Culberg was struck by their resemblance to a landform he knew from northwestern Greenland, with peaks about 2 meters tall, separated by about 50 meters and extending about 800 meters.
“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 said.
The water pocket in Greenland was about 15 meters below the surface, likely less than 10 meters thick and about 1.6 kilometers wide.
If the same process spawned Europa’s many double ridges, each associated water pocket could boast a volume similar to Lake Erie, one of North America’s Great Lakes.
“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 coauthor Dustin Schroeder added.
"News Services" POPULAR ARTICLE
-
Dollar Edges Lower, Yen at 34-year Trough
-
A Strong Earthquake Shakes Taiwan, Damaging Buildings and Causing a Tsunami
-
Taiwan’s Strongest Earthquake in 25 Years Kills Seven, Traps 77 (UPDATE 2)
-
Iranian Consulate in Damascus Flattened in Suspected Israeli Air Strike
-
Japan’s Nikkei Climbs 1.5% as Investors Scoop Up Beaten-Down Stocks (Update 1)
JN ACCESS RANKING
- M6.0 Earthquake Hits Japan’s Tohoku Region; Fukushima, Iwate, Miyagi Prefectures Observe 4 on Japanese Scale With No Risk of Tsunami
- Cherry Blossoms Draw Crowd to Tokyo’s Ueno Park; Viewing Season Kicks Off to Slow Start
- China Mutes Memorialization of Reformer Hu Yaobang; Memories Could Spark Critique of Xi Administration
- Shinkansen Services Suspended After Man ‘Searches for Phone’ on Tracks; Disruption Affects About 14,000 Passengers
- Whaling Mother Ship Built in Japan for 1st Time in 73 Years