Ringing rings reveal Saturn’s innards

Vibrations induced by planet send signals about interior’s structure

Saturn

RINGED GIANT  Saturn’s rings cast a shadow on the planet in a 2012 Cassini spacecraft photo. Subtle vibrations in those rings are helping scientists explore the structure of the gas giant’s interior.

NASA/JPL-Caltech/Space Science Institute

BALTIMORE — Saturn is surrounded by a vast seismometer: its rings.