University of Iowa's Don Gurnett Captures Sound of Solar Storm

News Services
University of Iowa
Iowa City, Iowa

CONTACTS:
Gary Galluzzo, 319-384-0009,

Oct. 30, 2003

UI's Don Gurnett Captures Sound Of Solar Storm

Although no major electrical problems have yet resulted from the current series
of solar flares bombarding the Earth, University of Iowa Professor and Space
Physicist Don Gurnett, recently used NASA's Cassini spacecraft to record the
sound of one of the largest solar flares seen in decades as it moved outward
from the sun.

The radio wave burst, resembling the clicking of an old-fashioned telegraph
machine followed by the rush of a jet engine, was recorded Tuesday, Oct. 28, by
Cassini while on its way to a July 1, 2004, encounter with Saturn and its moons
and rings. Gurnett noted that the radio waves -- moving at the speed of light --
took just 69 minutes to reach the spacecraft, currently some 8.7 AU distant from
the Earth. (One AU, or astronomical unit, is the distance from the Earth to the
sun -- about 93 million miles.)

"This is one of the biggest events of its kind ever seen," said Gurnett, a
veteran of more than 25 major spacecraft projects, including the Voyager 1 and
Voyager 2 flights to the outer planets, the Galileo mission to Jupiter, and the
Cassini mission to Saturn. The event, described as a "type III" radio burst, was
detected using the 86-pound Cassini radio and plasma wave instrument, largely
built at the UI and for which Gurnett serves as principal investigator. The
sound can be heard on-line by visiting Gurnett's web site at:
http://www-pw.physics.uiowa.edu/space-audio/

"The sound is produced by electrons moving out from the solar flare, beginning
at a high frequency before dropping to a lower frequency," Gurnett said.
Scientists monitoring the solar flare said that the massive cloud -- composed of
billions of tons of electrically charged particles -- reached the Earth on
Thursday, Oct. 29, but no major power outages were reported.

Gurnett is also part of a NASA-funded, Italian-U.S. project called MARSIS (Mars
Advanced Radar for Subsurface and Ionospheric Sounding) to search for
underground water on Mars, a project whose radar instrument is aboard the
European Space Agency's (ESA) Mars Express spacecraft. A member of the National
Academy of Sciences, Gurnett has seen his 40 years of collected space sounds
serve as the inspiration for the NASA-commissioned and critically acclaimed
music and visual composition "Sun Rings," composed by Terry Riley and performed
around the world by the famed Kronos Quartet.