Paris: A day on Saturn is 10 hours, 32 minutes and 45 seconds long, said a study Wednesday that further demystifies the ringed gas giant.
Saturn's rotation period had long left scientists scratching their heads -- the sixth-furthest planet from our sun has no solid object on its surface to allow easy observation of the speed at which it spins.
NASA's Voyager spacecraft had previously used radio measurements to calculate a rotation of 10 hours 39 minutes and 22.4 seconds, while the Cassini space traveller came up with 10 hours 47 minutes and six seconds.
The latest calculation, which the study authors believe to be the most accurate yet, was based on measurements of Saturn's gravitational field, and adjusted for the planet's shape and density.
To confirm their findings, the team applied the same method to measure, and confirm, the rotation of Saturn's gassy neighbour Jupiter, whose speed was already well-known.
"An accurate determination of Saturn's rotation period has important implications for understanding its atmospheric dynamics and internal structure," study co-author Ravit Helled of Israel's Tel Aviv University told AFP by email.
Knowledge of the internal structure, in turn, "provides important information on the formation process of gas giant planets".
The new measurement implied that Saturn's core was smaller than previously estimated, said Helled.
The method may in the future be used to derive the rotation periods of other giant planets.