A team of scientists recently published a study indicating that Saturn’s famous rings may be the result of the collision of an ancient moon with the planet regarding 160 million years ago, according to RT.
The study says that the moon, called Chrysalis, orbited the gas giant for several billion years before colliding with it and disintegrating.
Scientists from the Massachusetts Institute of Technology (MIT) performed calculations that determined changes in Saturn’s rotation axis over time.
The results indicate that another object once orbited around it, but when it got too close to the gas giant, it disintegrated into pieces and formed those distinctive rings around Saturn.
The loss of this moon also explains why Saturn tilts at an angle of 26.7 degrees in its rotation, which is indicated by its fast rings.
The planet’s tiny rings, which are only 150 million years old, and have a tilt of regarding 26.7 degrees relative to their orbit around the sun, appear too large to form when Saturn itself formed.
“Just like a butterfly cocoon, this moon was dormant for a long time and suddenly became active and the rings appeared,” said lead author of the study, Professor Jack Wisdom.
Since the early 2000s, astronomers have believed that Saturn’s tilt is associated with the planet’s “orbital resonance” with its neighbor Neptune.
Two planets have an “orbital resonance” if their periods of rotation are simultaneous and they exert a uniform gravitational influence on one another.
The “resonance” theory arose because Saturn would “advance” – or oscillate – as it rotated at roughly the same rate as Neptune’s orbit.
But observations by NASA’s Cassini spacecraft, which orbited Saturn from 2004 to 2017, suggested that Titan, Saturn’s largest moon, might in fact be responsible for the wobble.
This is because Titan is migrating away from Saturn faster than expected, at a rate of regarding 11 centimeters per year, so it was thought that the moon’s gravity might tilt the planet.
However, this theory relies on Saturn’s moment of inertia – or how mass is distributed in the planet’s interior – which is still unknown.
Its tilt can behave differently, depending on whether the material is more concentrated and denser in its core or toward the surface.
Scientists have used some of Cassini’s recent observations to map Saturn’s gravitational field. They then used that data to model the distribution of mass within the planet and calculate the moment of inertia (a physical term meaning the resistance of a stationary body to motion).
They were surprised to discover that the newly determined moment of inertia placed Saturn close to Neptune, but outside the range of resonance with Neptune.
This indicates that these two planets may have once been synchronous rotation, but no longer. And here the scientists said: “We looked for ways to remove Saturn from the echo of Neptune.”
The scientists re-examined the mathematical equations that describe how Saturn’s axis of rotation changes over time.
They hypothesized that the tilt of Saturn’s axis might be affected by the loss of the Moon, as this would have taken it out of Neptune’s echo.
For these phenomena to occur, the 84th hypothetical moon, Chrysalis, must be the size of Iapetus, the planet’s third largest satellite.
The team concluded that Chrysalis, while in orbit, pulled Saturn in a way that kept its tilt consistent with that of Neptune.
However, it is likely that the Moon entered a chaotic orbital region sometime between 200 and 100 million years ago.
This means that the satellite experienced a number of close encounters with Iapetus and Titan, and eventually came very close to Saturn regarding 160 million years ago.
The collision tore Chrysalis to pieces, allowing Saturn and Neptune to lose their echo as the Moon’s gravitational influence disappeared.
The constant outward migration of Titan and its effect on the Saturn-Neptune echo mean that Saturn’s tilt subsequently decreased, but remained at its current value of 26.7 degrees.
A small portion of Chrysalis’ mass remained suspended in orbit, and it shattered into icicles and formed rings of this debris.
Professor Wisdom added: “It’s a very good story, but, like any other result, it needs to be scrutinized by other scientists as well.”
 "Taiwan Holds First Tabletop Exercise Simulating Chinese Military Threat")