How did Saturn Moon Tethys get Those Weird Stripes?

NASA’s Cassini mission has been orbiting Saturn for over a decade, so you’d be forgiven in thinking that it’s seen just about every weird feature on the ringed gas giant and its fascinating system of moons. But in new observations beamed back from Cassini, icy moon Tethys has only now decided to show off its mysterious stripes.

Using clear, green, infrared and ultraviolet spectral filters, during a flyby in April, Cassini’s cameras were able to create a color-enhanced view of the 660 mile (1,060 kilometer) wide ice-encrusted moon. And that’s when mission scientists saw them — long stripes of red discoloration arcing across the surface.

Although stripes that appeared slightly red have been spotted in previous flybys, the angle between the Saturnian system, the sun and Cassini has not been ideal. But as Saturn’s northern hemisphere has been entering summer these past few years, the northern stripes on Tethys have gradually come into view and now Cassini has recorded vivid red features that at first appear to be fairly young on geological timescales.

“The red arcs really popped out when we saw the new images,” said Cassini participating scientist Paul Schenk of the Lunar and Planetary Institute in Houston, Texas, in a NASA news release. “It’s surprising how extensive these features are.”

“The red arcs must be geologically young because they cut across older features like impact craters, but we don’t know their age in years.” added Cassini imaging scientist Paul Helfenstein, of Cornell University, Ithaca, New York. “If the stain is only a thin, colored veneer on the icy soil, exposure to the space environment at Tethys’ surface might erase them on relatively short time scales.”

Reddish bands are also found on Jupiter’s moon Europa, which is known to host a subsurface ocean. Europa’s streaks are colored by hydrated salts mixed with chemicals like magnesium sulfate or sulfuric acid. This chemistry is thought to be caused by a complex interplay between the liquid subsurface ocean and possible tectonics in Europa’s icy crust, leading to speculation about the possibility of a circulation of nutrients from the icy surface to the ocean below, potentially supporting an extraterrestrial biosphere.

Read more at Discovery News