This true color mosaic of Jupiter was constructed from images taken by the
narrow angle camera onboard NASA's Cassini spacecraft on December 29, 2000,
during its closest approach to the giant planet at a distance of approximately
10 million kilometers (6.2 million miles).
It is the most detailed global color portrait of Jupiter ever produced; the
smallest visible features are approximately 60 kilometers (37 miles) across. The
mosaic is composed of 27 images: nine images were required to cover the entire
planet in a tic-tac-toe pattern, and each of those locations was imaged in red,
green, and blue to provide true color. Although Cassini's camera can see more
colors than humans can, Jupiter's colors in this new view look very close to the
way the human eye would see them.
Everything visible on the planet is a cloud. The parallel reddish-brown and
white bands, the white ovals, and the large Great Red Spot persist over many
years despite the intense turbulence visible in the atmosphere. The most
energetic features are the small, bright clouds to the left of the Great Red
Spot and in similar locations in the northern half of the planet. These clouds
grow and disappear over a few days and generate lightning. Streaks form as
clouds are sheared apart by Jupiter's intense jet streams that run parallel to
the colored bands. The prominent dark band in the northern half of the planet is
the location of Jupiter's fastest jet stream, with eastward winds of 480
kilometers (300 miles) per hour. Jupiter's diameter is eleven times that of
Earth, so the smallest storms on this mosaic are comparable in size to the
largest hurricanes on Earth.
Unlike Earth, where only water condenses to form clouds, Jupiter's clouds are
made of ammonia, hydrogen sulfide, and water. The updrafts and downdrafts bring
different mixtures of these substances up from below, leading to clouds at
different heights. The brown and orange colors may be due to trace chemicals
dredged up from deeper levels of the atmosphere, or they may be byproducts of
chemical reactions driven by ultraviolet light from the Sun. Bluish areas, such
as the small features just north and south of the equator, are areas of reduced
cloud cover, where one can see deeper.
