SaturnSupercomputer simulations suggest that the ring may have been formed by the collision of two icy moons millions of years ago. NASA. The discovery provides new insights into the Saturn system and raises questions about potential life on its moons.
On a clear night, with a decent amateur telescope, Saturn and its remarkable series of rings can be seen from the Earth’s surface. But how were those rings made? And what can they tell us about Saturn and its moons, one of the potential places NASA hopes to search for life? A new series of supercomputer simulations reveals the origins of the rings provided an answer to the mystery of a large-scale collision at a time when dinosaurs still roamed the earth.
According to a new study published on September 27th, of astrophysical journal NASA and its partners say Saturn’s rings may have evolved from the debris of two icy moons that collided and shattered hundreds of millions of years ago. Debris that didn’t end up falling into the rings may also have contributed to the formation of some of Saturn’s modern moons.
“There’s still a lot we don’t know about the Saturn system, including the moons that host environments that may be suitable for life,” said Jacob Kegereis, a research scientist at NASA’s Ames Research Center in Silicon Valley, California. “There is,” he says. “So it’s interesting to use large-scale simulations like this to investigate in detail how they evolved.”
A new simulation from NASA and Durham University has proposed a theory for the origin of Saturn’s rings and icy moons. They may have formed after a massive collision of two moons orbiting a gas giant. The simulations used in this study are some of the most detailed of their kind to study the formation of Saturn’s rings and potentially habitable icy moons. Credit: NASA/Jacob Kegerreis/Luís Teodoro
High resolution simulations and new insights
NASA’s Cassini mission helped scientists understand how young Saturn’s rings and perhaps some of its moons are astronomically. And that knowledge has led to new questions about how they formed.
To learn more, the research team turned to the Distributed Research using Advanced Computing (DiRAC) supercomputing facility at Durham University in the UK. They modeled what different collisions between precursor satellites would look like. These simulations were run at more than 100 times higher resolution than previous similar studies using the open source simulation code SWIFT, giving scientists the best insight into the history of the Saturn system. did.
Currently, Saturn’s rings lie close to the planet, within a range known as the Roche limit. The Roche limit is the farthest orbit in which a planet’s gravity is strong enough to collapse large chunks of rock or ice if it gets any closer. Material orbiting further out may aggregate to form satellites.
Role of ice and collision mechanics
By simulating about 200 different versions of the impact, the researchers found that a wide range of impact scenarios could throw just the right amount of ice into Saturn’s Roche limit, where it could settle in the rings.
And while no alternative explanation has been offered for why Saturn’s rings are almost rock-free, this type of impact could explain it, since Saturn’s rings are made almost entirely of ice. be.
“This scenario naturally leads to an ice-rich ring,” said Vincent Eke, associate professor in Durham University’s Department of Physics/Institute of Computational Cosmology and co-author of the paper. “When icy progenitor moons collide with each other, the rock in the core of the colliding object is less widely dispersed than the ice above it.”
Fragments of ice and rock could also collide with other moons in the system, setting off a series of collisions. Such synergies may have destroyed other progenitor moons outside the ring, from which today’s moons formed.
Effects of gravity and future research
But what caused these events in the first place? Two of Saturn’s former moons were affected by usually small effects in which the Sun’s gravity “added” and destabilized their orbits around Saturn. may have led to a collision. If the orbits are configured correctly, the extra gravitational pull from the Sun can cause a snowball effect, or “resonance,” where the Moon’s normally circular, flat orbit is stretched and tilted until the orbits intersect. , resulting in a high-speed collision.
Saturn’s moon Rhea currently orbits just above where the moon encounters this resonance. Similar to Earth’s moon, Saturn’s moons move outward from the planet over time. Therefore, if Rhea were ancient, it would have had more than resonance in the recent past. However, Rhea’s orbit is very circular and flat. This suggests that it has not experienced the destabilizing effects of resonance and has instead formed more recently.
New research is consistent with evidence that Saturn’s rings formed recently, but big unanswered questions remain. If at least some of Saturn’s icy moons are also young, what does that mean for the potential for life in the subsurface oceans of worlds like Enceladus? Can we uncover the full story behind this study? Future research based on this study will help us learn more about this fascinating planet and the icy world that orbits it.
References: “Recent impact origins of Saturn’s rings and medium-sized moons” LFA Teodoro, JA Kegerreis, PR Estrada, M. Ćuk, VR Eke, JN Cuzzi, RJ Massey, TD Sandnes, September 27, 2023. astrophysical journal.
DOI: 10.3847/1538-4357/acf4ed