A recent study published in The Astrophysical Journal has utilized supercomputer simulations to provide an explanation for the origin of Saturn’s rings. The research, conducted by NASA, the University of Durham, and the University of Glasgow, suggests that the rings could have formed from the remains of two smaller icy moons that collided and shattered hundreds of millions of years ago. These progenitor moons would have been similar in size to Saturn’s current moons, Dione and Rhea. Some of the debris from this collision may have also contributed to the formation of Saturn’s current moons.

This new insight into the origins of Saturn’s rings was made possible by data collected by the Cassini spacecraft, which spent 13 years studying Saturn and its systems. Cassini’s measurements showed that the rings are primarily composed of ice and have accumulated very little dust since their formation. This indicates that the rings formed relatively recently in the history of the solar system.

To further investigate the formation of the rings, the research team used the COSMA supercomputer at the University of Durham’s DiRAC facilities. They conducted hydrodynamic simulations with a resolution more than 100 times higher than previous studies. By modeling different collisions between progenitor moons, the researchers gained valuable insights into the history of Saturn’s system.

The simulations revealed that the impact between icy moons could have sent enough material near Saturn to form the rings. This scenario naturally leads to the creation of ice-rich rings, as the rock in the cores of the colliding bodies disperses less widely than the ice covering it. These findings support the idea that the rings originated from a collision between two moons, rather than other alternative explanations.

By simulating various collision scenarios, the researchers determined that a wide range of impacts could disperse the appropriate amount of ice within Saturn’s Roche limit. This is the region where a planet’s gravitational force can break apart larger bodies composed of rock or ice. The dispersed ice could then settle into rings as icy as those observed around Saturn today.

Dr. Jacob Kegerreis, a research scientist at NASA’s Ames Research Center, highlighted the importance of these simulations in understanding the Saturn system. He emphasized that much is still unknown about Saturn and its moons, including the possibility of suitable environments for life. The new simulations provide a detailed exploration of the system’s evolution, shedding light on the geological youth of Saturn’s rings.

Overall, this study offers compelling evidence that Saturn’s rings and moons resulted from a massive collision in the relatively recent history of the solar system. Supercomputer simulations have provided valuable insights into the formation of these celestial features, contributing to our understanding of the dynamics and evolution of the Saturn system.

– L. F. A. Teodoro et al, A Recent Impact Origin of Saturn’s Rings and Mid-sized Moons, The Astrophysical Journal (2023).