An artist’s concept of the Cassini orbiter crossing Saturn’s ring plane. New measurements of the rings’ mass give scientists the best answer yet to the question of their age. Image credit: NASA/JPL-Caltech
The rings of Saturn may be iconic, but there was a time when the majestic gas giant existed without its distinctive halo. In fact, the rings may have formed much later than the planet itself, according to a new analysis of gravity science data from NASA’s Cassini spacecraft.
The findings indicate that Saturn’s rings formed between 10 million and 100 million years ago. From our planet’s perspective, that means Saturn’s rings may have formed during the age of dinosaurs.
The conclusions of the research – gleaned from measurements collected during the final, ultra-close orbits Cassini performed in 2017 as the spacecraft neared the end of its mission – are the best answer yet to a longstanding question in Solar System science. The findings were published online 17 January 2019 in Science.
Saturn formed 4.5 billion years ago, in the early years of our Solar System. There have been clues that its ring system is a young upstart that attached to Saturn years afterward. But how long afterward?