Saturn moons younger than previously thought: Study

New York: Saturn's moons may be younger than previously thought, says a study based on freshly-harvested data from NASA's Cassini mission.

"All of these Cassini mission measurements are changing our view of the Saturnian system, as it turns our old theories upside down," said Radwan Tajeddine from Cornell University in the US.

Tajeddine is a member of the European-based Encelade scientific team that pored over the Cassini data.

The Encelade team provided two key measurements in the research -- the rigidity of the tidal bulge, or the Love number - named for Augustus E.H. Love, a famed British mathematician who studied elasticity - and the dissipation factor, which controls the speed at which moons move away.

While Saturn is mostly a gigantic shroud of liquid hydrogen and liquid helium, it contains a rocky core -- about 18 times the size of Earth, which responds to tidal forces from all of Saturn's major moons by bulging. 

The forces of the bulging core, in turn, push the moons slightly away.

The team detected and examined the orbits of four tiny moons associated with the larger moons Tethys (Telesto and Calypso) and Dione (Helene and Polydeuces). 

While these tiny moons do not affect the tidal forces on Saturn, their orbits are disturbed by Saturn's core tidal bulges.

"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," Tajeddine said. 

"The moons are migrating away much faster than expected," Tajeddine said.

If Saturn moons actually formed 4.5 billion years ago, as currently believed, their current distances from the home planet should be greater, Tajeddine explained.

Thus, this new research -- published in the astronomy journal Icarus -- suggests, the moons are younger than 4.5 billion years, favouring a theory that the moons formed from Saturn's rings.

"What we believe about Saturn's moons history might still change in the coming years with the finale of the Cassini mission," lead researcher Valery Lainey of the Paris Observatory said.

"The more we learn about Saturn, the more we learn about exoplanets," Lainey noted.