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Israeli scientists time Saturn’s day

TA University scientists develop new method to determine rotation periods of the ringed planet, previously considered a mystery

Saturn and its moon Titan. (photo credit: NASA/JPL-Caltech/SSI)
Saturn and its moon Titan. (photo credit: NASA/JPL-Caltech/SSI)

A day on Saturn is 10 hours, 32 minutes and 45 seconds long, Israeli scientists revealed Wednesday, further demystifiing 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 traveler came up with 10 hours 47 minutes and six seconds.

The latest calculation, which planetary scientists Ravit Helled, Eli Galanti and Yohai Kaspi of Israel’s Tel Aviv University 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.

The Israeli team published their findings in the latest edition of American scientific journal Nature.

Israeli scientist Ravit Helled (photo credit: YouTube screen capture)
Israeli scientist Ravit Helled (photo credit: YouTube screen capture)

To confirm their findings, they applied the same method to measure, and confirm, the rotation of Saturn’s gassy neighbor 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 Helled 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.

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