December 4, 2013
Cassini Captures High-Res Video Of Saturn’s Hexagonal Jet Stream
redOrbit Staff & Wire Reports - Your Universe Online
“Spanning about 20,000 miles (30,000 kilometers) across, the hexagon is a wavy jet stream of 200-mile-per-hour winds (about 322 kilometers per hour) with a massive, rotating storm at the center,” the agency reported. “There is no weather feature exactly, consistently like this anywhere else in the solar system.”
“The hexagon is just a current of air, and weather features out there that share similarities to this are notoriously turbulent and unstable,” added Cassini imaging team member Andrew Ingersoll, a professor of planetary science at the California Institute of Technology. “A hurricane on Earth typically lasts a week, but this has been here for decades – and who knows – maybe centuries.”
On Earth, weather patterns are interrupted when they encounter friction originating from ice caps or landforms. Conversely, scientists believe the lack of solid land on Saturn, which is essentially just a massive gas ball, could play a role in the relative stability of the hexagon.
The high-quality images of this jet stream are available now because late last year, the sun began lighting up its interior. That allowed Cassini to snap images of the hexagon over the course of a 10-hour period using high-resolution cameras.
As a result, NASA researchers were finally able to closely examine the motion of the cloud-structures on the interior. They found the storm around the planet’s pole, as well as several small vortices rotating in the opposite direction of the hexagon itself. The largest of those vortices were said to span 2,200 miles, or double the size of the largest hurricane ever witnessed on Earth, the researchers said.
“Inside the hexagon, there are fewer large haze particles and a concentration of small haze particles, while outside the hexagon, the opposite is true," said Dr. Kunio Sayanagi, a member of the Cassini imaging team and a professor at Hampton University in Virginia. “The hexagonal jet stream is acting like a barrier, which results in something like Earth's Antarctic ozone hole.”
“The Antarctic ozone hole forms within a region enclosed by a jet stream with similarities to the hexagon,” NASA officials added. “Wintertime conditions enable ozone-destroying chemical processes to occur and the jet stream prevents a resupply of ozone from the outside. At Saturn, large aerosols cannot cross into the hexagonal jet stream from outside and large aerosol particles are created when sunlight shines on the atmosphere.”