MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109 TELEPHONE (818) 354-5011
Contact: Jane PlattApril 3, 1998
FOR IMMEDIATE RELEASE:
NEW CLASS OF DUST RING DISCOVERED AROUND JUPITER
Scientists have found evidence for a new ring of dust that
occupies a backward orbit around Jupiter, based on computer
simulations and data from NASA's Galileo spacecraft, it is
reported in today's issue of Science magazine.
A team led by researchers at the University of Colorado at
Boulder reported that a faint, doughnut-shaped ring of
interplanetary and interstellar dust some 1,126,000 kilometers in
diameter (about 700,000 miles) appears to be orbiting the giant
planet. Evidence for the new ring's existence comes from
computer simulations that correlate with data collected by a dust
detector aboard the Galileo spacecraft has detected this ring by
capturing some of its dust, said Dr. Joshua Colwell, a research
associate at the university's Laboratory for Atmospheric and
Surprisingly, the researchers say, most of the interstellar
and interplanetary dust particles appear to be in a "retrograde"
orbit -- that is, moving in the opposite direction of the
rotating planet and its moons, Colwell said. The reason for the
backward orbit of the tiny particles is not yet clear, he said.
The paper in Science magazine was authored by Colwell,
research associate Dr. Mihaly Horanyi, also of the Laboratory for
Atmospheric and Space Physics, and planetary scientist Dr.
Eberhard Grun of the Max Planck Institute for Astrophysics in
Heidelberg, Germany, who is the principal investigator on
Galileo's dust detector.
The Galileo mission is managed by NASA's Jet Propulsion
Laboratory (JPL), Pasadena, CA. JPL is a division of the
California Institute of Technology, Pasadena, CA.
NASA's Voyager 2 detected an uneven dust ring around Jupiter
in 1979 that scientists believe was created by the collisions of
small moonlets with micrometeoroids in the Jovian system. But
the newly identified ring of dust with smoke-size particles
originating from beyond the Jovian system appears to be much
larger, more sparse and, possibly unique in the solar system.
"I suspect we may wind up seeing something similar at
Saturn," said Colwell. Launched in 1997, NASA's Cassini
spacecraft will reach the ringed planet in 2004.