Spiders from Mars? Try Europa.
A team of planetary scientists from Ireland have examined and named an interesting feature on the surface of Jupiter’s icy moon that resembles the shape of a spider, or possibly an exploding star.
They called it “Damhán Alla,” which is Gaelic for “spider,” or, in a particularly evocative phrasing, “wall devil.”
The team’s analysis, published as research in journal of planetary sciencesuggesting that Damara and other similar features may be festering wounds caused by water erupting from Europa’s icy crust.
“The implications of our study are truly exciting,” lead author Lauren Mc Keown, a physicist at the University of Central Florida, said in a statement. “Surface features like this can tell us a lot about what’s going on beneath the ice. If we see more of these features with Europa Clipper” — NASA’s new space probe currently en route to Jupiter — they could point to local pools of salt water below the surface.
Europa, the smallest of Jupiter’s four Galilean moons, has piqued the interest of astronomers because it is suspected of harboring a salty ocean beneath its icy surface, making it one of the most promising candidates for extraterrestrial life in the solar system. Its spider-like features were first observed during NASA’s Galileo mission, which lasted from 1989 to 2003, during which the spacecraft flew by Europa 11 times.
In the study, McKeown’s team compared Dam’ara, which is about a kilometer in diameter, to similar formations on Earth called lake stars and sometimes ice stars. Lake stars are usually only a few feet in size. When snow falls on a frozen lake, holes form in the ice and the water melts some of the snow in radiating, branching patterns. Scientists call these patterns dendritic patterns, and the pattern they saw on Europa’s surface is another sign of water breaking through its surface.
In this case, the hypothesis is that some kind of impact on the moon’s icy shell caused salty water to seep into the broken ice. It also suggests the existence of a vast underground ocean, or at least small pools of water beneath the surface.
“Lake stars are really beautiful, and they’re common on frozen lakes and ponds covered in snow or slush,” McKeown said. “It’s great to think that they could give us a glimpse into the processes happening on Europa and even other icy ocean worlds in the solar system.”
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