New simulations shed light on origins of Saturn’s rings and icy Moons 

According to new research involving NASA and Durham and Glasgow Universities, Saturn’s rings could have evolved from the debris of two progenitor icy moons that collided and shattered only a few hundred million years ago.   

They would likely have been similar in size to two of Saturn’s current moons, Dione and Rhea.   

Debris that didn’t end up in the rings could also have contributed to the formation of some of Saturn’s present-day moons.  

Building knowledge 

Most contemporary high-quality measurements about Saturn have come from the Cassini spacecraft that spent 13 years studying the planet and its systems after entering Saturn’s orbit in 2004.  

Analysis of Cassini data indicated that Saturn’s rings were much younger than first thought. 

To investigate this further, NASA and our Physicists turned to the COSMA supercomputer hosted at Durham as part of the UK’s DiRAC (Distributed Research Utilising Advanced Computing) facility. 

Simulating moon collisions 

The team modeled what different collisions between precursor moons in Saturn’s system may have looked like.    

These hydrodynamical simulations were conducted using the SWIFT open source software at a resolution more than 100 times higher than previous studies, giving scientists their best insights into the Saturn system’s history. 

 By simulating almost 200 different versions of the impact, the research team discovered that a wide range of collision scenarios could scatter the right amount of ice into Saturn’s Roche limit, where it could settle into rings as icy as those of Saturn today.   

Since other elements of the system have a mixed ice-and-rock composition, alternative theories haven’t been able to explain why there would be almost no rock in Saturn’s rings.   

Further research building on this work will help us learn more about this fascinating planet and the icy worlds that orbit it.   

Main image shows a simulation of an impact between two icy moons in orbit around Saturn, ejecting debris that could evolve into the planet's iconic and remarkably young rings.  Credit: NASA/Jacob Kegerreis/Luís Teodoro 

Find out more: 

• Durham's role in the research was led by Dr Vincent Eke in our Department of Physics and Institute of Computational Cosmology. Dr Eke worked with Dr Jacob Kegerreis, a former Durham PhD student now working at NASA Ames, and Luis Teodoro Honorary Research Fellow in the School of Physics & Astronomy at Glasgow University. 

• The research was published in the Astrophysical Journal (ApJ) and can be read in full here https://doi.org/10.3847/1538-4357/acf4ed 

• DiRAC (Distributed Research Utilising Advanced Computing) is funded by the UK’s Science and Technology Facilities Council. This national facility supports research in cosmology, astrophysics, particle physics and nuclear physics. 

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