Saturn’s tilt- caused by its moons- will increase over the next billion years

The influence of Saturn's satellites can explain the tilt of the rotation axis of the gas giant.


After Saturn’s formation, some dynamical mechanism must have tilted Saturn up to its current obliquity of 26.7°. This event is traditionally thought to have happened more than 4 Gyr ago during the late planetary migration.

Two scientists from CNRS and Sorbonne University working at the Institute of Celestial Mechanics and Ephemeris Calculation have recently discovered that Saturn’s moon can explain the tilt of the rotation axis gas giant. Their study suggests that the tilt will increase even further over the next few billion years.

Scientists found that Saturn’s rotation axis’s current tilt is caused by the migration of its satellites, especially by that of its largest moon, Titan.

Recent studies had shown that Saturn’s moons are moving away from Saturn much faster than previously thought. Scientists, in this study, incorparated this increased migration rate into their calculations. Based on their calculations, scientists concluded that this moving process affects the inclination of Saturn’s rotation axis: as its satellites move further away, the planet tilts more and more.

Scientists noted, “Saturn’s axis is still tilting, and what we see today is merely a transitional stage in this shift. Over the next few billion years, the inclination of Saturn’s axis could more than double.”

Journal References:
  1. Melaine Saillenfest, Giacomo Lari, Gwenaël Boué. The large obliquity of Saturn is explained by the fast migration of Titan. Nature Astronomy, 2021; DOI: 10.1038/s41550-020-01284-x
  2. Melaine Saillenfest, Giacomo Lari, Ariane Courtot. The future large obliquity of Jupiter. Astronomy & Astrophysics, 2020; 640: A11 DOI: 10.1051/0004-6361/202038432
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