Though best known for its rings, Saturn has another unusual--and unusually beautiful--feature. As you can see in spectacular new video footage taken by NASA's Saturn-orbiting space probe Cassini, the giant gaseous planet also sports a powerful six-sided jet stream that astronomers call "the hexagon."
First discovered by NASA's Voyager 1 space probe during its voyage through the outer solar system in the 1980s, the hexagon packs 200-mph winds and spans 20,000 miles across the planet's north pole. At its center is a giant rotating storm.
"The hexagon is just a current of air, and weather features out there that share similarities to this are notoriously turbulent and unstable," Andrew Ingersoll, a Cassini imaging team member at the California Institute of Technology in Pasadena, Calif., said in a written statement. "A hurricane on Earth typically lasts a week, but this has been here for decades--and who knows--maybe centuries."
What explains the hexagon's longevity? Astronomers say it may be because Saturn is composed of gas and thus, unlike Earth and other rocky planets, has no landforms to disrupt the fast-moving currents.
Saturn's orbit started to tilt its northern hemisphere toward the sun in late 2012, which better illuminated the hexagon and made this new video possible.
The images that make up the video, taken over a 10-hour period, are the first made using color filters that differentiate between the large and small haze particles that make up the hexagon. And while the images provide the best view yet of the hexagon, even better ones may be on the way.
"As we approach Saturn's summer solstice in 2017, lighting conditions over its north pole will improve, and we are excited to track the changes that occur both inside and outside the hexagon boundary," Scott Edgington, Cassini deputy project scientist at the Jet Propulsion Laboratory in Pasadena, said in the written statement.
The Cassini spacecraft was launched in 1997 and has been orbiting Saturn since 2004.