Saturn’s Perfect Storms

Saturn’s Perfect Storms

Hurricanes are examples of planet-scale storms best seen from orbit
Credit: NOAA

Saturn is the windiest planet in the solar system, which is one mystery of the ringed giant. Imagine not what qualifies as a terrestrial hurricane with category five status assigned beyond one hundred miles-per-hour. On Saturn the superstorms can produce a thousand mph wind. The close-up banner view shows lots of atmospheric detail, including a dark storm and wisps of clouds. The dark spot is noticeably lighter around its perimeter than in its interior. Saturn storms brew in both the northern and southern hemispheres but take on their highest winds at the equator.

The hurricanes on Saturn can begin with cloud masses nearly the size of the entire Earth. As the storms grow, it is not unusual for a single storm to grow to engulf the equivalent of thirty Earths.

Storms at Saturn’s equator move eastward at speeds up to 450 meters per second (1000 mph), which is about 10 times the speed of the Earth’s jet streams and approximately three times greater than the equatorial winds on Jupiter.

Saturn’s rings are just one of the unique attractions, including moons and storms.
Credit: NASA/JPL

The image was taken with the Cassini spacecraft narrow angle camera on Sept. 10, 2004, at a distance of 8.8 million kilometers (5.5 million miles) from Saturn, through a filter sensitive to wavelengths of infrared light centered at 750 nanometers.

The image scale is 52 kilometers (32 miles) per pixel. The image has been contrast enhanced to improve visibility of features in the atmosphere. The right images show an unscaled comparison to a terrestrial hurricane (Frances) which depend on water temperature differences rather than upper atmospheric swirling winds on Saturn. When Earth storms hit land they begin to dissipate, but on Saturn a storm can circumnavigate the entire planet.

During the thirty-year Saturnian summers, heated gases rise on the sunward facing hemisphere. These warmer layers eventually become unstable at higher altitudes and ammonia rich clouds eventually produce ice-crystals.

Cassini’s big adventure with Saturn’s moon begins in earnest at the beginning of 2005, when the Huygens probe begins to descend to the surface of the largest moon Titan. European and American scientists hope to use Huygens to get a close-up view of what might provide analogies to what a very primordial Earth might have looked like, if it never progressed beyond an ice age. Just as Saturn seems like a miniature of our larger solar system, so too may its moons give a glimpse of what might have cooked up closer to the Sun than Saturn.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA’s Office of Space Science, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.

Related Web Pages

Build Your Own Planet
Eye through the Hurricane
Saturn Edition, Astrobiology Magaz.
Saturn’s Rings in UV
Cassini Closes In on Saturn

Saturn– JPL Cassini Main Page
Lord of the Rings
Space Science Institute, Imaging Team Boulder, Colorado
Saturn: The Closest Pass