By Richard Stenger
CNN.com Writer
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| This video of Jupiter's surface spans 24 rotations between
October 31 and November 9 (refresh browser to replay animation) |
PASADENA,
California (CNN) -- Scientists at Pasadena, California's Jet Propulsion
Laboratory are proclaiming victory in today's flyby of Jupiter
by the unmanned spacecraft Cassini. The spacecraft worked in concert
with another unmanned vehicle, Galileo, to transmit new images
of our solar system's largest planet back to Earth.
The primary
goal of the experiments is to study the effect of solar wind on
Jupiter's magnetic field. The study captured data for the first
time showing that atoms from the solar wind were escaping the
magnetic field, scientists said during a news conference on Saturday.
The solar
wind consists of streams of ionized gas particles flowing from
the sun, which gently push matter throughout the solar system.
The scientists
said the next step was to attempt to measure the changes in Jupiter's
magnetic field created by the solar wind. Experts want to know
whether the atoms registered by the experiment were escaping the
magnetic field because of the solar wind's effect or because of
natural fluctuations in the field itself.
Other images
from Galileo and Cassini offer a chance to learn more about Jupiter's
weather patterns and about volcanic activity on its moon, Io.
Cassini, a
joint project by NASA and the European and Italian space agencies,
passed Jupiter at about 2 a.m. PST on Saturday at a distance of
10 million kilometers (6 million miles), primarily to gain a slingshot-like
boost from the planet's gravity to help the spacecraft reach the
planet Saturn by July 2004.
But Galileo,
in permanent orbit around Jupiter, may be the real hero of the
mission. It has outlived its designed two-year life span by three
years, giving scientists the opportunity to use their so-called
"double team" method of studying the planet.
A film
by Cassini
NASA released
Cassini's first color movie of Jupiter earlier this week. The
short clip presents the entire circumference of the planet, flattened
into the form of a rectangle.
Like a similar
map of the Earth, the most extreme northern and southern latitudes
are stretched out considerably. The smallest discernable details
at the equator are about 600 kilometers (about 370 miles) across.
In the video,
the Great Red Spot swirls, orange and white storm bands slide
against each other and black dots appear to reveal the shadow
of passing moons in the video, which spans 24 Jupiter rotations
between October 31 and November 9.
To the east
(right) of the Red Spot, oval storms roll over each other like
ball bearings. Small, bright features appear quickly and randomly
in turbulent regions, possible signs of lightning storms. The
smallest visible features at the equator are about 600 kilometers
(370 miles) across. In a map of this nature, the most extreme
northern and southern latitudes are unnaturally stretched out.
Scientists
are interested in Jupiter's weather patterns in hopes of using
their data to learn more about weather patterns on Earth.
Production
trouble
On Thursday,
Cassini, which cost $3.4 billion, was forced to switch to a different
maneuvering system. Engineers said they suspect the problem began
when a lubricant on the wheel was gradually reduced, causing friction
on the bearings.
Cassini's
wheels point the spacecraft. When an electric motor spins one
of the wheels, the spacecraft rotates in the opposite direction.
The wheel
system has been trouble-free since it was put back in operation
December 21, the Jet Propulsion Laboratory said. The JPL manages
the mission for NASA, the U.S. space agency.
Coming
attractions
Other synchronized
studies of the largest planet in the solar system are in the works.
Before Cassini leaves the Jupiter system, it will take pictures
of the planet's night-side aurora in January.
At the same
time, back in Earth orbit, the Hubble telescope, orbiting Earth,
will train its powerful lens on Jupiter's day-side aurora.
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