October 7, 2009

Saturn's Super-Sized Ring

NASA scientists discover a huge new ring around Saturn

By Suzanne Zimbler

When you think of Saturn, you probably picture a planet surrounded by colorful rings. For years, Saturn was known to have seven main rings. But on Tuesday, NASA scientists announced that they had spotted an eighth.

NASA/PA/AP Saturn's never-before-seen ring is the largest in the solar system.

This never-before-seen ring is not only Saturn's biggest. It is also the largest in our solar system. "This is one super-sized ring," said Anne Verbiscer, one of the astronomers who worked on the study. According to scientists, the ring is so huge that it would take one billion Earths to fill it.

Seeing Rings

Four hundred years ago, Galileo got the first glimpse of Saturn's rings using his telescope. NASA scientists also used a telescope to spot the new ring. The Spitzer telescope, launched in 2003, orbits the sun while taking pictures of faraway objects in space.

The new ring is almost invisible to the human eye. But the Spitzer telescope can detect the glow of extremely cold objects, such as the giant ring, which is minus 316ºF. "By focusing on the glow of the ring's cool dust, Spitzer made it easy to find," said Verbiscer.

Made of Moondust

NASA Scientists think the giant ring is made up of dust from Saturn's moon Phoebe.

The colossal hoop circles Saturn from a distance of eight million miles. It is 50 times farther away from Saturn than the planet's other rings. It also has a completely different tilt.

The giant ring is made up of a thin layer of dust. Scientists think the dust comes from Saturn's moon Phoebe. Why? Phoebe orbits within the ring. Its dents and marks make it clear that Phoebe has been hit many times by space rocks and clumps of ice. Each time Phoebe is hit, dust flies into space and goes into orbit, adding particles to the giant ring.

Moon-Made Mystery

The discovery of the new ring may also provide scientists with an answer to a mystery. Another of Saturn's moons, lapetus, has a bright side and a very dark side. Scientists have long wondered why. With the discovery of the new ring, they now believe that dust from the giant ring is moving toward Saturn and slamming into lapetus.

"Astronomers have long suspected that there is a connection between Phoebe and the dark material on lapetus," said scientist Douglas Hamilton. "This new ring provides convincing evidence of that relationship.

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