Hubble Images Show Saturn's Rings

Associated Press

PASADENA, Calif. (AP) - The Hubble Space Telescope has caught Saturn's rings in full tilt, revealing new clues about the origin of the gossamer band that encircles the giant planet.

The images, captured at approximately 12-month intervals from 1996 through last year but only released this week, show the planet as its northern hemisphere swings from fall to winter.

With each passing year, Saturn's seasonal motion reveals more and more of its rings to Hubble's view. The process is slow, since Saturn takes more than 29 years to complete one lap around the sun, making each ``season'' on the planet equal to more than seven Earth years.

Since Saturn's rings are only some 30 feet thick, they are practically invisible when viewed edge-on. The most recent image, however, captures Saturn as its tilt reaches its extreme, or winter solstice in the planet's northern hemisphere.

The image shows the rings of dusty water and ice to be a subtle salmon color.

``The color of the ring material can help tell us what the rings are made of and will help decipher their origin,'' said Jeff Cuzzi, a National Aeronautics and Space Administration scientist and member of the Hubble team, in a statement. The images were released this week at the 198th meeting of the American Astronomical Society in Pasadena.

Scientists think the pale red color comes from complex organic molecules mixed in with the ice. While Saturn's seven icy moons do not share that color, many objects frozen in the deeper reaches of the outer solar system do.

That leads them to speculate that the origin of the rings is not Saturn itself, but an object that traveled close to the planet. Saturn's gravity would have presumably torn the object apart and scattered the debris in orbit. The planet's gravitational field constantly disrupts the chunks of ice, keeping them spread out and from forming into a new moon.

Scientists will get a closer look at the rings of Saturn after the robotic Cassini spacecraft arrives at the planet in 2004. The Hubble telescope was launched in 1990.