True and False
December 16, 2004
Jupiter Clouds, True Color and False to Show Heights
January 23, 2001
These two frames of composited images taken by NASA's Cassini spacecraft show the same cloud patterns on Jupiter both in natural color (left) and in a false-color combination (right) selected to show differences in clouds' height. The white spots in the right frame are storms high in the atmosphere.
Each frame is a combination of images taken by Cassini's narrow-angle camera through different filters on Dec. 31, 2000, one day after Cassini's closest approach to the planet. The smallest features are roughly 60 kilometers (40 miles) across.
The left frame shows the colors Jupiter would have if seen by the naked eye. The right frame is composed of three images. Two were taken through filters centered on regions of the spectrum where the gaseous methane in Jupiter's atmosphere absorbs light, and the third was taken in a red continuum region of the spectrum, where Jupiter has no absorptions. The combination yields an image whose colors denote the height of the clouds. Red regions are deep water clouds, bright blue regions are high haze (like the blue covering the Great Red Spot). Small, bright white spots are energetic lightning storms that have risen to a height where there is no opportunity for absorption of light, so the clouds reflect all light equally. The darkest blue regions , such as the long linear regions bordering the northern part of the equatorial zone, are the very deep `hot spots' from which Jovian thermal emission is free to escape to space.
This is the first time that global images of Jupiter in all the methane and appropriate continuum filters have been acquired by a spacecraft. From images like these, the dynamics of the layers within Jupiter's atmosphere will be determined.
Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini mission for NASA's Office of Space Science, Washington, D.C.
Credit: NASA/JPL/University of Arizona
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