NASA has the latest photos captured by the spacecraft, Cassini, from one of Saturn's moon, Tethys, and it is baffling scientists.
Prominently seen in Tethys' surface are deep red arc-shaped streaks. It looks as if a graffiti artist spray painted on them. "The red arcs really popped out when we saw the new images," said Paul Schenk of the Lunar and Planetary Institute in Houston in a press release. "It's surprising how extensive these features are."
Scientists still do not know what these red streaks are, nor do they have any hints as to their origin, but there are some assumptions that it could be caused by chemical impurities outgassing and flowing outside of Saturn's moon.
"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," said imaging scientist Paul Helfenstein from Cornell University in the same press statement. "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," he added.
Cassini captured the images using different sets of spectral filters -- clear, infrared, ultraviolet and green -- which helped enhance the photos. The subtle red color was highlighted as a result, when it was otherwise not immediately visible before. Comparing other photos taken from previous orbits by Cassini, the red arcs were faintly present.
Cassini has been traveling the planet Saturn and its moons since 2004 and the latest images were taken in April. NASA said it plans to take a closer look at Tethys and its red arcs via Cassini in November.
"As the Saturn system moved into its northern hemisphere summer over the past few years, northern latitudes have become increasingly well illuminated. As a result, the arcs have become clearly visible for the first time," the space agency said, according to cNET.
