Blog Archives

Saturn’s Rings: An Accessible Astrophysical Disk – Matthew Tiscareno (SETI Talks)

Saturn’s ring system is an astrophysical disk that is neither light-years away nor billions of years in the past. We can visit this disk at close range and observe a number of phenomena that also operate in disks of other kinds. As a result, we see small-scale processes that shape ring texture, connect those processes to the bodies and structures that cause them, and watch closely as the disk changes with time.

We will discuss recent Cassini observations that elucidate disk processes including 1) “self-gravity wakes” and “spiral density waves,” both of which were originally proposed for galaxies but are observed with exquisite precision in Saturn’s rings, 2) “propeller” features caused by 100-meter to km-sized moonlets embedded in the disk; these are the first objects ever to have their orbits tracked while embedded in a disk, rather than orbiting in free space, and hold the potential of deepening our understanding of planetary migration, and 3) irregular edge shapes in the gaps opened up by larger moons (10 km and more), which may hold clues to angular momentum transport.

Ultra-lightweight Probes to Catalyze Interstellar Exploration – John Rather (SETI Talks)

Based on present space science and engineering, interstellar travel remains highly unlikely. Applying synergistic emerging technologies to enhance capabilities for accelerated space development in the solar system may catalyze possible steps to the stars. A stepwise sequence of plausible projects will be proposed. The remarkable present progress in diverse applied sciences can be a game changer.