Saturn Rotation Faster, Day Shorter Than Previously Thought

Researchers in Tel Aviv claim to have accurately measured Saturn's rotation period after decades of struggle to arrive at a universally-acceptable number.

According to the new research, a day on Saturn is 10 hours, 32 minutes and 44 seconds long, six minutes shorter that what Voyager 2 probe determined more than two decades ago. Voyager 2's measurements were cast into doubt on earlier occasion after Cassini made different measurements in mid-2000s. This led to the conclusion that a gas giant like Saturn does not yield to traditional means of measuring a planet's rotation, and thus the need for other methods.

Part of the problem lies in the Saturn's dense atmosphere and lack of solid mass which makes direct observations difficult, reports Science Magazine. However researchers at University of Tel Aviv developed statistical method that helps determine rotation period with smallest margin of error. Researchers made use of Saturn's gravitational field and the fact that the planet's east-west axis is shorter is than north-south axis.

"The rotation period of a giant planet is a fundamental physical property, and its value affects many aspects of the physics of these planets, including their interior structure and atmospheric dynamics. We were determined to make as few assumptions as possible to get the rotational period. If you improve your measurement of Saturn's gravitational field, you narrow the error margin," said Ravit Helled, who devised the method.

To test the method, researchers turned to Jupiter and found the calculations agreed with well-established measurements.