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Space Topics: JupiterThe Year in Pictures: 2007New Horizons: Jupiter's Turbulent Terminator
Turbulent clouds whirl at every visible scale in this scan by New Horizons across much of Jupiter’s disk. New Horizons happened to pass by Jupiter during a period of global upheaval—new storms have been appearing, old ones are disappearing or changing shape, and entire bands of Jupiter’s atmosphere are changing color. To prevent New Horizons’ sensitive optical instruments—designed for much dimmer lighting conditions—from being overwhelmed by the brilliant light at Jupiter’s distance from the Sun, this view was taken along the day-night boundary known as the terminator. At the terminator, the Sun illuminates Jupiter’s cloud tops almost from the side, so “topography” in Jupiter’s clouds creates light and dark shading. Near the center of this image, in the beige band, there is a subtle fishbone-like vertical striping of mesoscale waves in Jupiter’s atmosphere. These waves are somewhat like ocean or earthquake waves: the wave crests and troughs move with a speed that is independent of the motion of the atmosphere. In this case, the atmosphere is moving—that is, the wind is blowing—at a speed of about 100 meters per second (200 miles per hour); the mesoscale waves are moving at 200 meters per second (400 miles per hour). The image was taken by New Horizons’ Multispectral Visual Imaging Camera using filters sensitive to blue light and to infrared light at a wavelength of 890 nanometers, where methane—an important component of Jupiter’s clouds—strongly absorbs light. Where Jupiter appears reddish, methane is blocking our view into the atmosphere; where the planet appears bluish, the sky is relatively cloud-free, so we are peering through cloud gaps deeper into the atmosphere. |
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