Cassini Probe Spies Source of Saturn's Jet Streams

Cassini Probe Spies Source of Saturn's Jet Streams
The image shows small-scale, sheared-out cloud features associated with turbulent eddies in the vicinity of one of Saturn's eastward flowing jet streams, or "jets." (Image credit: NASA/JPL/Space Science Institute)

The Cassini spacecraft circling Saturn has returned images of immense rotating storms that appear to be the powerhouse behind the ringed planet's jet streams.

Saturn's giant rotating storms -- or eddies -- feed into the planet's swift jet streams, much like rotating gears can power a conveyor belt, by pumping them with energetic winds, Saturn researchers announced Tuesday.

"The new information about how Saturn's jet streams are powered is exactly the opposite of what we thought prior to Cassini," said the study's leader Anthony Del Genio, a Cassini imaging scientist at NASA's Goddard Institute for Space Studies in New York City.

Jet streams are regions in which the motions of a planet's atmosphere swiftly blow winds east or west. On Saturn, jet streams can blow 10 times faster than they do on Earth and reach speeds of up to 1,000 miles (1,609 kilometers) per hour, NASA researchers have said.

Researchers had previously thought Saturn's eddies would siphon energy from the planet's jet streams, not amplify them, due to atmospheric friction and tugging between storms.

"We knew the eddies were powering the jets because they were pointing in the same direction and carrying the same momentum in that direction," said Andrew Ingersoll, a Cassini imaging team member at the California Institute of Technology in Pasadena, California.

Similar interactions between swirling storm eddies and jet streams have been seen on Earth and, more recently, in the cloud banks of Jupiter, but the new Cassini findings are a first for Saturn. On Earth, a pair of well-known jet streams circle the planet in the northern and southern hemisphere.

Scientists used Cassini's observations to track cloud movements during successive images taken about 10 hours apart, or about one Saturn rotation, to link the planet's storm eddies and jet streams. The research is detailed in the solar system-focused science journal Icarus.

Additional images of Saturn's southern hemisphere suggest the process occurs on a planet-wide scale and explains why the ringed world's alternating bands of eastward and westward jet streams have remained constant despite decades of observations, researchers said.

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  • Special Report: Cassini's Ongoing Mission to Saturn and its Moons

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Tariq is the Editor-in-Chief of Space.com and joined the team in 2001, first as an intern and staff writer, and later as an editor. He covers human spaceflight, exploration and space science, as well as skywatching and entertainment. He became Space.com's Managing Editor in 2009 and Editor-in-Chief in 2019. Before joining Space.com, Tariq was a staff reporter for The Los Angeles Times covering education and city beats in La Habra, Fullerton and Huntington Beach. In October 2022, Tariq received the Harry Kolcum Award (opens in new tab) for excellence in space reporting from the National Space Club Florida Committee. He is also an Eagle Scout (yes, he has the Space Exploration merit badge) and went to Space Camp four times as a kid and a fifth time as an adult. He has journalism degrees from the University of Southern California and New York University. You can find Tariq at Space.com and as the co-host to the This Week In Space podcast (opens in new tab) with space historian Rod Pyle on the TWiT network (opens in new tab). To see his latest project, you can follow Tariq on Twitter @tariqjmalik (opens in new tab).