This bizarre six-sided feature encircle the north pole of Saturn near 78 degrees north latitude. This image is one of the first clear images ever taken of the north polar region as seen from a unique polar perspective.

Originally discovered and last observed by a spacecraft during NASA’s Voyager flybys of the early 1980’s, the new views of this polar hexagon taken in late 2006 prove that this is an unusually long-lived feature on Saturn.

This image is the first to capture the entire feature and north polar region in one shot, and is also the first polar view using Saturn’s thermal glow at 5 microns (seven times the wavelength visible to the human eye) as the light source. This allows the pole to be revealed during the night-time conditions presently underway during north polar winter. Previous images from Voyager and from ground-based telescopes suffered from poor viewing perspectives, which placed the feature and the north pole at the extreme northern limb (edge) of the planet.

To see the deep atmosphere at night, the infrared instrument images the thermal glow radiating from Saturn’s depths. Clouds at depths about 75 kilometres lower than the clouds seen at visible wavelengths block this light, appearing dark in silhouette.

To show clouds as features that are bright or white rather than dark, the original image has been contrast reversed to produce the image shown here. The nested set of alternating white and dark hexagons indicates that the hexagonal complex extends deep into the atmosphere, at least down to the 3-Earth-atmosphere pressure level, some 75 kilometres underneath the clouds seen by Voyager.

Multiple images acquired over a 12-day period between 30 October and 11 November 2006, show that the feature is nearly stationary, and likely is an unusually strong pole-encircling planetary wave that extends deep into the atmosphere.

Credits: NASA/JPL/University of Arizona

The 30 on October 2006, from an average distance of 1.3 million kilometres.

In this image, the red color indicates the amount of 5-micron wavelength radiation, or heat, generated in the warm interior of Saturn that escapes the planet. Clouds near 3-bar (about 100 kilometres deeper than seen in visible wavelengths) block the light, revealing them in silhouette against the background thermal glow of Saturn. The bluish color shows sunlight striking the far limb (edge) of the planet, showing that the entire north pole is under the nighttime conditions characteristic of polar winter, as on Earth.

This image is the first to capture the entire feature and north polar region in one shot, and is also the first polar view using Saturn’s thermal glow at 5 microns (seven times the wavelength visible to the human eye) as the light source. This allows the pole to be revealed during the persistent night-time conditions under way during winter. The hexagon feature was originally discovered by NASA’s Voyager spacecraft in 1980, but those historic images and subsequent ground-based telescope images suffered from poor viewing perspectives, which placed the feature and the north pole at the extreme northern limb (edge) in those images.

In the new infrared images, the strong brightness of the hexagon feature indicates that it is primarily a clearing in the clouds, which extends deep into the atmosphere, at least some 75 kilometres underneath the typical upper hazes and clouds seen in the daytime imagery by Voyager. Thick clouds border both sides of the narrow feature, as indicated by the adjacent dark lanes paralleling the bright hexagon. This and other images acquired over a 12-day period between Oct. 30 and Nov. 11, 2006, show that the feature is nearly stationary, and likely is an unusually strong pole-encircling planetary wave that extends deep into the atmosphere.

Credits: NASA/JPL/University of Arizona

Here, brightness indicates the amount of 5-micron (seven times the wavelength visible to the human eye) radiation, or heat, generated in the depths of the warm interior of Saturn that escapes the planet. Clouds at a depth equivalent to 3-Earth-atmospheres pressure block the light radiating from below, revealing themselves in dark silhouette against the background thermal glow of the planet. These deep clouds lie some 75 kilometres underneath the typical ammonia hazes and clouds seen in visual imagery and are likely composed of ammonia-hydrosulfide, although some may be composed of water, as on Earth. A prominent feature seen in this polar view is a strange hexagon wave feature circumscribing the north pole.

This nighttime movie was acquired over a one-hour period on 10 November 2006, from an average distance of 1.03 million kilometres above Saturn’s clouds.

Credits: NASA/JPL/University of Arizona

This image is one of the first clear images of the north polar region ever acquired from a unique polar perspective. In this image, the blue color shows high-altitude emissions from atmospheric molecules excited by charged particles smashing into the atmosphere along Saturn’s powerful magnetic field lines, producing the aurora at very high altitudes in Saturn’s atmosphere. The red color indicates the amount of 5-micron wavelength radiation, or heat, generated in the depths of the warm interior of Saturn that escapes the planet. Clouds blocking this light are revealed as silhouettes against the background thermal glow of the planet.

This image is among the first to capture the entire hexagonal feature and north polar region in one shot. It is also one of the first polar views using Saturn’s thermal glow at 5 microns (seven times the wavelength visible to the human eye) as the light source. This allows polar cloud features to be revealed during the persistent nighttime conditions under way during north polar winter.

The strong brightness of the hexagon feature indicates that it is primarily a clearing in the clouds, which extends deep into the atmosphere, at least down to the 3-bar (3-Earth atmospheres pressure) level, about 75 kilometres below the clouds and hazes seen in visible wavelengths. Thick clouds border both sides of the narrow feature, as indicated by the adjacent dark lanes paralleling the bright hexagon. This image and other images acquired over a 12-day period between 30 October and 11 November 2006, show that the feature is nearly stationary, and likely is an unusually strong pole-encircling planetary wave that extends deep into the atmosphere.

Credits: NASA/JPL/University of Arizona