`Mind-blowing' images from Saturn's orbit

From millions of miles away, Cassini illuminates the rings

July 02, 2004|By Dennis O'Brien | Dennis O'Brien,SUN STAFF

Seven years after its launch, the Cassini spacecraft began sending back "mind-blowing" images this week of an interstellar icon: the rings of Saturn.

The images released by NASA yesterday show in black and white simplicity the network of icy particles that make up the rings around the sixth rock from the sun. Cassini beamed back hundreds of images Wednesday night and yesterday morning as it dived between the rings and arced within 12,500 miles of Saturn - the closest it will come to the planet.

"The funny thing is, there's a lot about the rings we really don't know," said Josh Colwell, a planetary ring specialist at the University of Colorado at Boulder.

Scientists say the rings that have intrigued mankind since they were discovered in the 1600s might hold clues about the origin of Earth. Believed to be only a few hundred million years old, the rings are considered a dynamic model of what our solar system looked like before dust particles joined to form planets more than 4 billion years ago.

Jupiter, Uranus and Neptune also have ring patterns, but none is as intricate as Saturn's.

"Saturn is the crown jewel of ring planets," Colwell said.

NASA scientists in California said yesterday that they plan to spend months poring over the images - and others to be released in the weeks ahead - to glean information about the composition of Saturn's rings. They also expressed wonder at their beauty.

"I'm surprised at how surprised I am at the beauty and the clarity of these images. They are shocking to me" and "mind-blowing," said Carolyn Porco, NASA's imaging team leader and a planetary ring specialist.

Discovered by Galileo in 1610 and first described in 1659 by Dutch astronomer Christiaan Huygens, the rings comprise particles - some are grain-sized, others are as big as barns - made mostly of a watery ice. Among the mysteries is why they are pinkish in color.

Cassini was launched in 1997. The $3 billion mission is being supervised by scientists at NASA's Jet Propulsion Laboratory in Pasadena, Calif.

It's funded by NASA, the European Space Agency and the Italian Space Agency, and it represents two decades of work by scientists.

Over the next four years, the bus-sized spacecraft will orbit Saturn 76 times, using five telescopes to take 300,000 images of the planet, its moons and its rings.

The instruments include one radio telescope, two infrared telescopes and one that reads ultraviolet light. The added wavelengths will give scientists a better understanding of the rings' composition, scientists say.

"There's carbon and there's soot in the rings," said Jeff Cuzzi, another University of Colorado scientist working with NASA. "They're highly evolved. They're the way they are because of gravitational forces; there's been collisions with asteroids and you have all this interaction with Saturn's moons and its magnetic field."

The mission also is designed to gather information about the largest of Saturn's 31 moons, Titan. The moon is shrouded by an atmosphere of nitrogen and methane and is believed to have organic compounds resembling those on Earth billions of years before life appeared.

Cassini will release a 700-pound probe, Huygens, that the European Space Agency will land on Titan to collect data about its surface and atmosphere.

Cassini slipped into obit around Saturn on Wednesday night, slowing down so that it could be captured by Saturn's gravity. NASA's broadcast of the maneuver over the Internet attracted millions of viewers in Maryland and across the world.

About 170 people filtered through NASA's Goddard Space Center to watch the progress on a projection-screen television Wednesday night. Yesterday, about 15 children observed a live question-and-answer session focused on Cassini at the Maryland Science Center.

"If things keep going as smoothly as it's been going, we won't have anything to worry about," said Hasso Niemann, a Goddard scientist who will use a spectrometer aboard the Huygens probe to begin taking measurements of Titan's atmosphere in January.

Sun staff writer Albert Hill contributed to this article.

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