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PHOTO CAPTION                             P-37539

This false-color image is a near-infrared map of
lower-level clouds on the night side of Venus,
obtained by the Near Infrared Mapping Spectrometer
aboard the Galileo spacecraft as it approached the
planet's night side on February 10, 1990. Bright
slivers of sunlit high clouds are visible on the
limb at top and bottom. The spacecraft is about
100,000 kilometers (60,000 miles) above the planet.
The image was constructed using an infrared
wavelength of 2.3 microns (about three times the
longest wavelength visible to the human eye).

The map shows the turbulent, cloudy middle atmosphere
some 50 to 55 kilometers (30 to 34 miles) above the
surface, 10 to 16 kilometers (6 to 10 miles) below the
visible cloud tops. The red color represents the radiant
heat from the lower atmosphere (about 400 degrees
Fahrenheit) shining through the sulfuric acid clouds,
which appear as much as 10 times darker than the bright
gaps between clouds. This cloud layer is at about
-30 degrees Fahrenheit, at a pressure of about one half
Earth's surface atmospheric pressure.

Near the equator, the clouds appear fluffy and blocky;
farther north, they are stretched out into east-west
filiments by winds estimated at more than 70 meters per
second (150 miles per hour), while the poles are capped
by thick clouds at this altitude.

The Galileo project is managed for NASA's Office of Space
Science and Applications by JPL; its mission is to study the
planet Jupiter and its satellites and magnetosphere after
multiple gravity-assist flybys at Venus and the Earth.

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