In May Dr Phil Sutton presented his ongoing work on the interactions between gravitational waves and planetary rings.
It was discussed that orbital resonances between objects in astrophysical systems is commonplace, with nearby moons creating clear structures in planetary rings. In Saturn’s rings the most obvious is caused by a 2:1 orbital resonance with the moon Mimas (below) in the form of the Cassini Division. By treating gravitational waves as an oscillation of the local gravitational field it can be shown that similar resonant like structures can form in a planetary ring. Due to an orbital period on the order of ~0.5 days in the ring very low frequency gravitational waves were able to be investigated.
The seminar closed on an important idea that the use of astrophysical objects as detectors might open up new parts of the elusive gravitational wave spectrum, and subsequent new areas of fundamental physics to be studied.