Saturn's Ring Rhythm
Radio signals sent by NASA's Cassini spacecraft to Earth through Saturn's rings revealed the presence of highly unusual regular formations of densely grouped ring particles. The harmonic ring structure caused the radio signal frequency to separate into three distinct components. The observed frequencies determine the regular spacing to be as small as 100 meters (320 feet), the finest-scale ring structure observed so far.
The regularly spaced yellow grid depicts the harmonic structure in Saturn's inner Ring A, and the image on the bottom right shows an actual observed frequency pattern (spectrogram). Color represents the observed signal strength. The structure acts like an enormously extended natural diffraction grating that separates the signal frequency into the three distinct components shown. The frequencies determine the regular spacing of the diffraction grating, 160 meters (500 feet) in this case. The image of Saturn was taken with Cassini's cameras and is shown here to illustrate the occultation.