Shop Windows to the Universe

Dig into Montana Before History: 11K Years of Hunter-Gatherers in the Rockies and Plains by D. H. MacDonald, Ph.D. See our online store book collection.
This image shows the strange hexagon feature located near Saturn's north pole. The infrared image was taken by the Cassini spacecraft in orbit around Saturn on October 29, 2006. Scientist think the hexagon may be some sort of wave in the planet's atmosphere.
Click on image for full size
Image courtesy NASA/JPL/University of Arizona.

Saturn's Strange Hexagon

Astronomers have discovered a bizarre, hexagon-shaped feature in the clouds of Saturn near the planet's North Pole. The feature was first seen in images returned by the Voyager spacecraft in the 1980s, and was later observed using the Hubble Space Telescope. In each case, however, the hexagon was hard to see - it was near Saturn's limb (edge) as viewed from each perspective (Voyager's and Hubble's) - and scientists weren't quite sure what to make of their observations. Now, the Cassini spacecraft that is currently orbiting Saturn, has returned an image of this strange phenomenon as viewed from above Saturn's North Pole. And scientists still aren't quite sure what to make of it!

They think the hexagon, which was imaged by an infrared camera on Cassini in October and November 2006, is some sort of wave in Saturn's atmosphere about 75 kilometers beneath the planet's visible cloud tops. Astronomers are still not sure why the feature has such a regular shape; nor why it is so long-lived, having been around since the time of Voyager's flyby in the early 1980's.

The infrared Cassini images of the feature show heat rising from Saturn's interior. Light colored areas are warmer, indicating that the IR radiation in those areas is escaping relatively unimpeded. Darker areas are places where clouds in Saturn's upper atmosphere are at least partially blocking the IR "light"; in effect, these are silhouettes of the "backlit" clouds. These clouds lie somewhere between 75 and 100 kilometers (47-62 miles) deeper in Saturn's atmosphere than the typical ammonia hazes and clouds seen in visible light wavelength views of the ringed planet's upper atmosphere. Scientists think the lower clouds that form the silhouettes in the IR images are likely composed of ammonia-hydrosulfide, although some may be composed of water, as is the case on Earth.

Notice how the hexagon is bright, but is bracketed on either side by dark areas. This apparently indicates that the hexagon is a relatively clear area in the atmosphere that allows us to see deeper into Saturn's interior. It also shows us that fairly thick clouds form on either side of this clear area. Scientists don't yet know the significance of this, but these clues may eventually help them figure out the nature of Saturn's strange hexagon.

The hexagon is located at roughly 78 degrees north latitude. The image shown on this page was captured by Cassini on October 29, 2006, from an average distance of 902,000 kilometers (560,400 miles) above the cloud tops of Saturn.

Last modified January 20, 2009 by Randy Russell.

Shop Windows to the Universe Science Store!

Our online store includes books on science education, classroom activities in The Earth Scientist, mineral and fossil specimens, and educational games!

Windows to the Universe Community

News

Opportunities

You might also be interested in:

Traveling Nitrogen Classroom Activity Kit

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

The Poles of Saturn and Its Moons

There's a lot of strange and interesting stuff going on at both the North and South Poles of Saturn. Features at the poles of two of Saturn's moons, Titan and Enceladus, have also grabbed the attention...more

Voyager

The rare geometric arrangement of planets Jupiter, Saturn, Uranus, and Neptune in the 1980's made it possible for the Voyager spacecrafts to visit them over a 12 year span instead of the normal 30. They...more

Hubble Space Telescope

The Hubble Space Telescope (HST) was one of the most important exploration tools of the past two decades, and will continue to serve as a great resource well into the new millennium. The HST is credited...more

Cassini

The Cassini probe began its journey to Saturn on October 15, 1997. It flew by Earth in August, 1999, before heading towards the distant planet. Cassini passed Jupiter in 2000 and then burned towards its...more

An Overview of Saturn's Atmosphere

The dramatic appearance of Saturn stems mainly from the spectacular rings. What is visible of the atmosphere is much less dramatic. The clouds of Saturn are much less colorful than those of Jupiter. This...more

Ammonia - NH3

Ammonia is a chemical compound that is a colorless, flammable gas at normal temperatures and pressures. Ammonia is toxic, corrosive to some materials, and has a pungent odor. An ammonia molecule (NH3)...more

An Overview of Motions in Saturn's Atmosphere

The most important motions in the atmosphere are winds. The major winds in Saturn's atmosphere are the zonal winds which are composed of alternating belts and zones flowing in opposite directions. Belts...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA