Saturn's Moons Could Be Younger Than Previously Thought
A new study based on newly received data from the Cassini spacecraft revealed that the moons orbiting the ringed planet Saturn could be younger than previously thought.
The study, published in the astronomy journal Icarus, showed that the current distance of the moons from the ringed planet is too short. This suggests that the moons are younger than the previously accepted 4.5 billion years. Additionally, the study also backs the theory that the moons were formed from the rings of Saturn.
For the study, the researchers pored over data sent by Cassini and examined the orbits of Saturn's four tiny moons associated the larger moons. The smaller moons Telesto and Calypso are associated with the larger moon Tethys, while Helene and Polydeuces are associated with Dione.
The researchers used two key measurements to determine how fast the moons are migrating away from the suns. These parameters used are the so-called Love number and dissipation factor. Love number, which is named for famous British mathematician Augustus E.H. Love, is the rigidity of the tidal bulge. Meanwhile, dissipation factors controls the speed at which the moons migrate away from their home planet.
Saturn's rocky core, which is about 18 times the size of Earth, responds to the tidal forces of the major moons orbiting the planet by bulging. The forces of the bulging core the push the moons slightly away. The researchers concentrated on the orbits of the four tiny moons to separate the effects of the Love number and dissipation factors. They noted that the tiny moons do not affect the tidal forces on Saturn. However, the planet's core tidal bulges disturb their orbits.
"By monitoring these disturbances, we managed to obtain the first measurement of Saturn's Love number and distinguish it from the planet's dissipation factor," explained Radwan Tajeddine, Cornell University research associate in astronomy and member of the research team, in a press release. "The moons are migrating away much faster than expected."
Tajeddine noted that if Saturn's moons actually formed 4.5 billion years ago, the current distances of these moons should be greater. The researchers also found the first evidence showing that a planet's dissipation factor can vary with its distance in relation to the moon. However, more studies are necessary to explain the mechanism behind these diffenrences.