The Cassini spacecraft delivered new images of Saturn's moon Tethys that shows strange red streaks on the surface that appear to make an arc.
According to a NASA press release unveiling the new image, the streaks are faint and narrow, almost resembling smudged lines drawn on the image after the fact with a marker.
"The red arcs really popped out when we saw the new images," Paul Schenk, a Cassini participating scientist at the Lunar and Planetary Institute in Houston, Texas, said in the release. "It's surprising how extensive these features are."
Such red marks are rare for Cassini to spot, as the spacecraft has been spending the last several years observing Saturn and its many moons. NASA noted "reddish marks" have only been spotted previously in craters on Dione's surface, as well as in certain features on the surface of Europa, which a moon belonging to Jupiter.
"The origin of the features and their reddish color is currently a mystery to Cassini scientists," NASA said in another statement. "Possibilities being studied include ideas that the reddish material is exposed ice with chemical impurities, or the result of outgassing from inside Tethys. The streaks could also be associated with features like fractures that are below the resolution of the available images."
"After 11 years in orbit, Cassini continues to make surprising discoveries," Linda Spilker, Cassini project scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif., said in the release. "We are planning an even closer look at one of the Tethys red arcs in November to see if we can tease out the source and composition of these unusual markings."
