Astro Night

Thu, November 07, 2019

When Saturn Became Lord of the Rings

Very recently new 20 moons were discovered to orbit planet Saturn bringing the
total number of known moons to 82. Last year, 12 additional moons were
announced to orbit Jupiter. The current total is 79. This talk will relate both
discoveries to our current picture of how the solar system formed. It will briefly
discuss this picture and what it tells us about the motion planets and most of the
moons. Then the talk will review the recent findings of the Cassini spacecraft that
spent 13 years in orbit around planet Saturn and made a number of remarkable
measurements of the planet and its satellites. During its final 22 orbits it dove in
between the planet and its rings where measured the planet's gravity fields with
unprecedented precision. Two important findings emerged. The winds on Saturn
are 9000 km deep, and the planet’s rings are incredibly young and formed only
10-100 million years ago. 100 million years ago dinosaurs still roamed on Earth.
They disappeared when a giant impact occurred near the Yucatan peninsula 65
million years ago. Now we have evidence that another drastic event occurred in
the Saturnian system that produced a gazillion pieces of icy rubble that make up
the rings today. This suggests that, one a million-year time scale, our solar
system is not as stable as one might assume.