A mysterious spider-like structure lurking on Jupiter's fourth-largest moon, Europa, may finally have a proper explanation, nearly 30 years after its discovery. The arachnid impostor was also given a new demonic name.
In March 1998 NASAThe Galileo spacecraft, which studied Jupiter and its main moons between 1995 and 2003, flew close to Europa, a frozen ocean moon often thought to be one of the most likely places for extraterrestrial life exist in the solar system. During this flyby the probe planned impact structure approximately 13.7 miles (22 kilometers) wide, dubbed the Manannan Crater, on the icy surface of the Moon, and discovered something strange lurking within it.
But in a new study published Dec. 2 in Planetary Science JournalThe researchers proposed an alternative explanation: the Jovian spider formed in a similar way to how dark dendritic structures known as “lake stars” typically form on Earth. These features form when snow falls on frozen lakes and water seeps through tiny holes in the ice.
With this in mind, researchers used a similar technique to partially recreate the mysterious shape of the Manannan crater in the laboratory. The research team also finally named Europa's arachnid star Damhan Alla, which means “spider” or “wall demon” in Irish. (Manannan is a Celtic god from Irish mythology, which partly inspired the new name.)
“Lake stars are truly beautiful, and they are quite common on snow-covered or slush-covered frozen lakes and ponds,” says the study's lead author. Laura McKeownThis was stated by a planetary scientist from the University of Central Florida. statement. “It’s exciting to think that they could give us insight into processes occurring on Europa and perhaps even other icy ocean worlds on our planet. solar system“
However, instead of water rising through tiny holes, as happens when lake stars form on Earth, Damkhan Alla was most likely born from an asteroid impact that created a small crack in Europa's icy shell, which allowed salty water to seep up and paint a spider-like pattern on the surface. (This asteroid impact likely occurred after the Manannan crater had already formed.)
The researchers also noted similarities between Damkhan Alla and the infamous “Martian spiders,” which are dust deposits on the surface of Mars. look like swarming spiders when viewed from above. These artificial arachnids, known as arachnids, are formed when sublimates of sublimated ice from carbon dioxideor turns directly into gas. McKeown's team previously recreated these features on Earth too much.
The similarity between Damkhan Alla's shape and spiders on Mars comes from the way “liquid flows through porous surfaces,” McKeown said. Theoretically, similar spider features could appear on other frozen ocean worlds, such as Saturn's moon EnceladusJupiter another moon Ganymede And dwarf planet Cereswhich is located in the asteroid belt beyond Mars.
Mac Keown is now setting up a new laboratory that will focus on studying how these different arachnid features can form on humans. different satellites of the solar system. She hopes she can provide valuable information to help inform NASA. Mission Europe Clipperwhich will be launched in October 2024 and will arrive in scrutinize Jupiter's watery moon in 2030.
“The significance of our study is truly impressive,” said Mac Keown. “Surface features like these can tell us a lot about what’s happening underneath the ice. If we see more of them with the Europa Clipper, they could point to local pools of salt water under the ice,” she added.
And these pools could be a good place to start looking for signs of extraterrestrial life.
