LASP Science Seminars

After exploring the Saturn system for more than 13 years, September 15th, 2017 marked the end of the NASA-ESA joint Cassini-Huygens mission. Before diving into and becoming a part of Saturn, the spacecraft witnessed a once-in-decades storm on the ringed gas giant, touring its magnificent ring system and icy moons scattered across the magnetosphere. The data it provided not only revised our fundamental understanding of the Saturnian system but also led to multiple discoveries altering the courses of planetary sciences and astrobiology. This seminar will focus on Saturn’s ring-moon system and the geologically active icy moon Enceladus. Saturn’s main rings were spotted by Galileo Galilei more than 400 years ago, yet its composition, dynamics, and origin remain an active field of study. In contrast, Enceladus, one of the most exciting Ocean Worlds in the solar system, was only found to be cryovolcanic active after Cassini’s close flyby in 2005. Its south-polar plume emission of water vapor, supplied from its sub-surface ocean, serves as the main source of Saturn’s magnetosphere, closely resembling Io’s role in Jupiter’s magnetosphere. One interesting possibility is that the evolution of Enceladus, which ultimately determines the existence of its subsurface ocean and corresponding astrobiology potential, may be closely coupled to the formation and evolution of Saturn’s Main Rings. Recent evidence, including in situ Cassini measurements and celestial dynamics analysis, argue Saturn’s rings to be younger than the last dinosaurs on Earth (< few 100s million years), contrary to the conventional assumption of an ancient ring-moon system formed with Saturn. In this presentation, I will discuss the theoretical and observational results of Saturn’s ring-moon system, including my works on probing these systems with nanodust measurements, and implications for future explorations in planetary sciences.