'Chinese lantern' technique helps track clouds at Saturn
Thu Oct 5, 2006 at 19:58 UTC
A new image of Saturn demonstrates a technique that creates a 'Chinese lantern' effect, showing Saturn's deep clouds silhouetted against the planet's warm, glowing interior.
Seen this way, Saturn's interior shows surprising activity underneath the overlying haze, with a great variety of cloud shapes and sizes. Because upper-level hazes and clouds obscure the view of these deep clouds in visible light, imaging clouds in the depths of Saturn is not practical using visible-light cameras.
Several recent images obtained by Cassini's visual and infrared mapping spectrometer were combined in a way that highlights the deep clouds in silhouette against the background radiation of heat generated by Saturn's interior. This literally lights the planet from the inside, like a lantern.
Clouds and hazes in Saturn's northern hemisphere are noticeably thinner than those in its southern hemisphere. This is thought to be a seasonal effect; this idea will be tested as Saturn's northern hemisphere enters springtime in the next few years.
Bright red colors indicate areas relatively free of deep-level clouds and particles, while darker red colors are cloudy regions. Images like these show Saturn's deep clouds under both daytime and nighttime conditions.
Image Credit: NASA/JPL/University of Arizona
Full resolution image.
This false-color mosaic of Saturn shows deep-level clouds silhouetted against Saturn's glowing interior. The image was made with data from Cassini's visual and infrared mapping spectrometer, which can image the planet at 352 different wavelengths.
This mosaic shows the entire planet, including features like Saturn's ring shadows and the terminator, the boundary between day and night.
The data were obtained in February 2006 at a distance of 1.6 million kilometers (1 million miles) from directly over the plane of Saturn's rings, which appear here as a thin, blue line over the equator. The image was constructed from images taken at wavelengths of 1.07 microns shown in blue, 2.71 microns shown in green, and 5.02 microns shown in red.
The blue-green color (lower right) is sunlight scattered off clouds high in Saturn's atmosphere and the red color (upper left) is the glow of thermal radiation from Saturn's warm interior, easily seen on Saturn's night side (top left), within the shadow of the rings, and with somewhat less contrast on Saturn's day side (bottom right). The darker areas within Saturn show the strongest thermal radiation. The bright red color indicates areas where Saturn's atmosphere is relatively clear. The great variety of cloud shapes and sizes reveals a surprisingly active planet below the overlying sun-scattering haze.
The brighter glow of the northern hemisphere versus the southern indicates that the clouds and hazes there are noticeably thinner than those in the south. Scientists speculate that this is a seasonal effect, and if so, it will change as the northern hemisphere enters springtime during the next few years.
Jet Propulsion Laboratory News Release
