PASADENA, Calif. – Scientists say they now believe rotating eddies are driving Saturn's jet stream winds, not the other way around.
The new view is based on images taken by the orbiting international Cassini spacecraft, which tracked the movement of cloud features on the ringed planet's southern hemisphere. Scientists initially believed eddies, or giant rotating storms, sapped energy out of the jets.
"Instead, what we find is that they are pumping energy into the jets," Cassini scientist Andrew Ingersoll of the California Institute of Technology said in a statement Tuesday.
The findings will appear in a future issue of the journal Icarus.
Jet streams are fast-moving currents that carry clouds in an eastern or western direction. By tracking the migration of clouds in images taken every 10 hours, scientists concluded the eddies were powering the jets because they were pointing in the same direction.
"The new information about how Saturn's jet streams are powered is exactly the opposite of what we thought prior to Cassini," said Anthony Del Genio of NASA's Goddard Institute for Space Studies in New York.
Cassini is a project of NASA, the European Space Agency and the Italian Space Agency. The spacecraft is managed by NASA's Jet Propulsion Laboratory in Pasadena.