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GIANT PLANET JUPITER
(left) and two
of its moons, lo and Europa, were pho·
tographed by Voyager 1 from 12 míllion
miles away. lo is seen passing over
Jupiter's Great Red Spot. Close-up of
turbulent Great Red Spot (lower left},
colorful scarred surface of lo (lower
center), and the Moon·fike appearance
of the Jovian satellite Ganymede show
the awesome and forbidding worlds re·
vealed by the Voyager mission.
lished theories about the formation of
the solar system may have to be ex–
tensively revised.
Speeding along at up to 84,000
miles per hour, Voyager also photo–
graphed the surfaces of the moons
Ganymede, Europa and Callisto, the
remaining Galilean moons. Callisto,
darkest and outmost of the Galilean
satellites, has a gigantic circular ha–
sin rimmed with wavelike ridges. Eu–
ropa seems to have an ice crust.
Yoyager photos of Ganymede
showed a desertlike floor crisscrossed
by faults or valleys that look like
marks made by dune buggies.
One of the greatest surprises of the
Yoyager probe was the discovery of a
flat thin ring of particles around the
equator of Jupiter. When only Sat–
urn was known to have such a ring
system, astronomers often considered
its formation to be a fluke. But in
March 1977, Uranus was also found
to have a ring. And now, Jupiter.
With three planets known to have
bracelets of extraplanetary material
around them, scientists are being
forced to come up with a reasonable
explanation. The "fluke hypothesis"
no longer seems viable.
Yoyager l is now headed for a close–
up look at Saturn, its rings and its
moons. But Saturn is about twice the
distance of Jupiter from the sun and
the spacecraft will not arrive until
November 1980. Meanwhile, another
probe, Yoyager 11, will arrive at Jupit–
er in July of this year, on the tenth
anniversaryof Apollo 11.
f
The unprecedented Yoyager ex–
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ploration of Jupiter, Saturn and
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other distant planets will provide new
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understanding of man's place in the
l
universe; at the same time, the stark
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desolation and hostile conditions on
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these alíen worlds should serve to re–
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mind us of our unique and precious
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home on planet Earth .
o
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