Space scientists have knocked 15 minutes off the length of a day on Saturn because the ringed planet is spinning faster than they thought.

The new measurement of Saturn’s rotation period is 10 hours, 32 minutes and 35 seconds, according to scientists Gerald Schubert, of the University of California, and John Anderson, of Global Aerospace, Los Angeles.

They based their figures on measurements made by Nasa’s Pioneer, Voyager and Cassini spaceprobes. The figure has been hard to pin down because Saturn is a giant ball of gas rather than a solid world like Earth.

The scientists admit their estimate is little more than a best guess. Any solid core is hidden deep below Saturn’s opaque layers of clouds.

Although 15 minutes might not sound a lot, it has great implications for understanding Saturn’s weather system. It means that winds there are blowing less rapidly than thought and in more than one direction.

Experts say it could even alter astronomers’ understanding of how such gas planets form, the journal Science reports. However, as the researchers admit, there is still much uncertainty over the true rotation period.

The Voyager probes, whose data was used, have now spent 30 years in space. The Nasa image above is from Cassini.

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