Icy moon of Saturn has mysterious red arcs on its surface

NASA's Cassini spacecraft has been hard at work for over a decade, and it continues to reveal surprising information about Saturn and its moons.

Photos beamed back to Earth in April show the icy lunar orb Tethys has narrow, curved red lines on its surface.

Though they look as they were spray-painted on, that's clearly not how they got there.

What caused them to form is currently a matter of speculation, as there's little precedent for their occurrence.

See photos of Saturn and its moons:

At this time, scientists believe that the arcs could be a result of impurities present in exposed ice or that the moon is perhaps outgassing from inside.

Regardless of how the marks developed, researchers say that they likely did so relatively recently.

Paul Helfenstein, a Cassini imaging scientist, noted, "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."

Follow-up investigations to take higher-resolution images are planned for later in the year.

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