ISO images Jupiter's atmosphere

Jupiter changes its appearance from image to image, as ESA's Infrared Space Observatory (ISO) examines the giant planet with a succession of filter settings. At 3.0 microns, Jupiter appears broadly similar to views by visible light, in which bright zones of clouds alternate with darker belts. Most luminous at this wavelength is the zone around the equator. The bright blob below the equator is Jupiter's Great Red Spot, created by a storm that has lasted for centuries. At 3.3 microns, Jupiter disappears. The blackout results from strong IR absorption of this wavelength by methane gas. The surrounding speckles have no meaning. Even the blackness of this image demonstrates ISO's ability to analyse the planet's chemistry. At 5.7 microns, regions of strong emissions in a northern belt appear as hot spots. They are dry, anti-cyclonic regions of sinking gas, where ISO is able to peer deep into the atmosphere. The hot spot emissions are strongest at 5.0 microns. At 7.6 microns, ISO is looking at the stratosphere, high in Jupiter's atmosphere. Notice the brightness of the south polar region, at the bottom of the image. At 9.4 microns, cloudy zones that were bright in the image above are relatively dark, while the intervening belts now outshine them. The Great Red Spot is also seen towards the bottom of the image. The position of the Great Red Spot shifts slightly to the right, from the first to the last image in this selection. Jupiter rotated noticeably on its axis during the time that ISOCAM spent examining the planet, in a single observing period of 35 minutes. [Image Date: 1997] [97.07.013-001]