Astronomers discover evidence of football-field sized moonlets in Saturn's A ring

The left image shows the B ring, Cassini Division, A ring and F ring, with the location of the propeller-shaped disturbances indicated. The center image is a closer view of the A ring, showing the radial locations where propeller features were spotted. In the right-hand image, the propellers appear as double dashes in the two close-up images. The unseen moonlets, each roughly the size of a football field, lie in the center of each structure. (The horizontal lines in the image represent electronic noise and do not correspond to ring features.)