"Exploring harmonies between giant planets and their rings"

Abstract: Planetary rings are exquisitely sensitive probes of gravitational fields and so can provide insights into the deep internal structure and dynamics of their host planets. In particular, Saturn's rings contain an array of tightly wound spiral patterns that are generated by normal mode oscillations and other asymmetries within that planet's interior. The observable properties of these ring patterns have already yielded the frequencies of many planetary normal modes, which have revealed that Saturn likely has a diffuse core and clarified how fast different parts of the planet rotate. At the same time, unexpected trends in the amplitudes or these normal modes and other time-variable patterns in the rings hint that Saturn has more complex internal dynamics than previously anticipated. More recently, efforts have started to determine whether ring structures could provide useful information about the internal structures of Uranus and Neptune, whose interiors are much less well understood. While a future mission may be needed to fully realize the potential of ring seismology with these planets, there are already hints of potentially interesting signals in the currently available data that merit a closer look.