ASTRONOMY PICTURE

OF THE DAY

EXPLANATION

The tiger stripes on Saturn’s moon Enceladus might be active. Even today, they may be spewing ice from the moon’s icy interior into space, creating a cloud of fine ice particles over the moon’s South Pole and creating Saturn’s mysterious E-ring. Recent evidence for this has come from the robot Cassini spacecraft now orbiting Saturn. Cassini detected a marked increase in particle collisions during its July flyby only 270 kilometers over a South Polar region of Enceladus. Pictured above, a high resolution image of Enceladus is shown from the close flyby. The unusual surface features dubbed tiger stripes are visible on the left in false-color blue. Why Enceladus is active remains a mystery, as the neighboring moon Mimas, approximately the same size, appears quite dead.

Credit

Cassini Imaging Team, SSI, JPL, ESA, NASA