The space probe Cassini gave astronomers a fresh look at Jupiter's moon and atmosphere as it swept past the planetary kingpin on the way to Saturn.
Researchers poring over the data collected in the flyby found that storms at the gas giant's poles appear more stable than their chaotic appearance belies, some lasting up to 70 days. Images and time-lapse movies recorded also show previously unseen jets stemming from the planet's poles and to appear confirm theories that erosion from Jupiter's tiny moons feed its thin belts. The flyby research appears in today's issue of the journal Science.
Cassini relayed about 26,000 images of the Jovian system, paying close attention to the planet's upper atmosphere, rings and some of its lesser-known moons. Other time-lapse movies include studies of Jupiter's ring-embedded moons Adrasea and Metis as they circle their parent and atmospheric studies of the planet's poles.
"It brought me to tears," said Carolyn Porco, team leader of the Cassini Imaging Central Laboratory of for Operations (CICLOPS), of the Jovian pass, which occurred over a six-month period starting in October 2000. "Even knowing the capability of Cassini's camera, I was still taken aback."
Cassini's Imaging Science Subsystem (ISS) consists of a pair of cameras, one narrow-angle and another wide, both equipped with filters to snap images all along the spectrum. Saturn-bound Cassini came within about six million miles (9.7 million kilometers) of Jupiter during the flyby, but relayed more information about the planet's atmosphere and magnetosphere than the Galileo probe - which arrived at the gas giant in 1995 - and the Voyager encounters of the 1980s, astronomers said.
The high-gain antenna onboard Galileo failed to deploy properly on the way to Jupiter, seriously affecting how much data the craft could send back Earthward at a time.
Porco told SPACE.com that the flyby may prove cause for atmospheric scientists to revisit their theories of how the Jovian atmosphere is thought to operate. Cassini's observations showed huge convective storms, similar to big thunderstorms on Earth - only bigger and longer, churning across Jupiter in dark belts, regions long thought to be the Jupiter equivalent of clear skies.
"We might need to revamp our ideas of where air is rising or descending for the planet," she said.
Cassini's Jupiter flyby was a great dress rehearsal for the probe's mission to Saturn, which promises to be awesome encounter.
"The flyby was really a freebie," Porco said. "But once Cassini reaches Saturn, it's going to be a feast for the eyes."
The Cassini probe is a collaboration between NASA, the European Space Agency and the Italian Space Agency. It should reach Saturn in July 2004, and carries with it the Huygens probe that will land on the planet's moon Titan.
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