"Sounds" of Outer Space Near Jupiter Now Online

December 15, 2000

NASA's Cassini spacecraft, approaching Jupiter, is detecting waves in the
thin gas of charged particles that fills the space between the Sun and its
planets. The waves are in low radio frequencies, which can be converted to
sound waves to make the patterns audible.

The waves presented here were detected by Cassini's radio wave and plasma
science instrument (RPWS) on Dec. 8, 2000, at a distance of about 23
million kilometers (14 million miles) from Jupiter. They are likely to
have derived from an interaction of the magnetic field that surrounds
Jupiter and the solar wind of particles speeding away from the Sun.

The oscillations discernible in the graph and in the audio file are from
ion-acoustic waves, which result from electrons moving in non-random
patterns driven by a flow of energy. In this case, the energy flow
probably comes from the heat of Jupiter's bow shock. The bow shock is
similar to a sonic boom from a supersonic jet flying through Earth's
atmosphere, except that the bow shock is caused by the supersonic solar
wind being diverted around Jupiter's magnetic field. The shock is a place
where the solar wind is heated, slowed and deflected by the magnetic field
surrounding Jupiter. Cassini has not reached the bow shock, but the shock
is probably the source of energy driving the waves that are reaching the

The period represented in the graph and audio file lasted 30 seconds. In
the process of presenting as sound waves what were originally electric
waves, the frequency has been sped up and a few short gaps have been
spliced out, resulting in a 10-second audio clip.

Cassini is a cooperative project of NASA, the European Space Agency and
the Italian Space Agency. The Jet Propulsion Laboratory, a division of the
California Institute of Technology in Pasadena, manages Cassini for NASA's
Office of Space Science, Washington, D.C.

For higher resolution image, click here.

Contact Information:

Prof. Donald A. Gurnett, donald-gurnett@uiowa.edu

or Dr. William Kurth, william-kurth@uiowa.edu

Department of Physics and Astronomy

University of Iowa

Van Allen Hall

Iowa City, IA 52242

Website: HREF="http://www-pw.physics.uiowa.edu/plasma-wave/cassini/home.html">http://www-pw.physics.uiowa.edu/plasma-wave/cassini/home.html

Additional information about Cassini is available online at:


The Cassini spacecraft is scheduled to arrive at Saturn in July 2004 to
begin a four-year exploration of the ringed planet and its moons. The
Cassini mission is managed by NASA's Jet Propulsion Laboratory in Pasadena,
Calif., for NASA's Office of Space Science, Washington, D.C. JPL is a
division of the California Institute of Technology in Pasadena.

Media Relations Office

Jet Propulsion Laboratory

California Institute of Technology

National Aeronautics and Space Administration

Pasadena, Calif. 91109.

Telephone (818) 354-5011

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