Huge Interplanetary Dust Storm Bombards Spacecraft : SCIENCE FILE: An exploration of issues and trends affecting science, medicine and the environment.

A huge dust storm brewing off Jupiter is bombarding the Galileo spacecraft on the way to the planet with as many as 20,000 electrically charged particles a day, sources at the Jet Propulsion Laboratory in Pasadena reported this week. It is the largest interplanetary dust storm ever measured.

Using a detector the size of a kitchen colander to collect and count the smoke-sized particles, Galileo has clocked the particles at speeds up to 450,000 m.p.h. But as yet, scientists are in the dark about their origins. They could be spewed from volcanoes on Jupiter’s fiery moon, Io, or part of Jupiter’s faint rings, or debris from the collision of the planet with comet Shoemaker-Levy last year.

JPL scientists hope to pinpoint the source of the storm once Galileo reaches Jupiter in December.