Article Posted on : - Sep 23, 2009

This image shows Saturn and its rings a day and a half after the Saturn equinox, when the sun shines directly over the planet's equator. Image credit: NASA

PASADENA (BNS): The Cassini spacecraft has captured images of Saturn’s rings during the planet’s equinox last month, revealing some interesting details about their shape and size.

The images, released by NASA on Monday, show the heights of some newly discovered bumps in the rings are as high as the Rocky Mountains. Scientists once thought the rings were almost completely flat.

“It's like putting on 3-D glasses and seeing the third dimension for the first time. This is among the most important events Cassini has shown us,” said Bob Pappalardo, Cassini project scientist at NASA's Jet Propulsion Laboratory here California.

On August 11, sunlight hit Saturn's rings exactly edge-on, performing a celestial magic trick that made them all but disappear. The spectacle occurs twice during each orbit Saturn makes around the sun in approximately 10,759 Earth days, or about 29.7 Earth years.

To capture the event, scientists for a week used the Cassini orbiter to look at puffy parts of Saturn's rings caught in white glare from the low-angle lighting. Scientists have known about vertical clumps sticking out of the rings in a handful of places, but they could not directly measure the height and breadth of the undulations and ridges until Saturn's equinox revealed their shadows.

“The biggest surprise was to see so many places of vertical relief above and below the otherwise paper-thin rings,” said Linda Spilker, deputy project scientist at JPL. “To understand what we are seeing will take more time, but the images and data will help develop a more complete understanding of how old the rings might be and how they are evolving.”

The chunks of ice that make up the main rings spread out 85,000 miles from the centre of Saturn, but they had been thought to be only around 30 feet thick in the main rings, known as A, B, C, and D.