* Astronomy

New observations by NASA's Cassini spacecraft indicate the rings of Saturn, once thought to have formed during the age of the dinosaurs, instead may have been created roughly 4.5 billion years ago, when the solar system was still under construction.
Larry Esposito, principal investigator for Cassini's Ultraviolet Imaging Spectrograph at the University of Colorado, Boulder, said data from NASA's Voyager spacecraft in the 1970s, and later from NASA's Hubble Space Telescope, led scientists to believe Saturn's rings were relatively youthful and likely created by a comet that shattered a large moon, perhaps 100 million years ago.
But ring features seen by instruments on Cassini -- which arrived at Saturn in 2004 -- indicate the rings were not formed by a single cataclysmic event. The ages of the different rings appear to vary significantly, and the ring material is continually being recycled.

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Saturn's shimmering rings may be as old as the solar system, scientists said Wednesday, debunking earlier theories that the rings were formed during the dinosaur age.
Astronomers had thought Saturn's rings were cosmically young, likely born some 100 million years ago from leftovers of a meteoric collision with a moon, based on data by NASA's Voyager spacecraft in the 1970s.
However, new data from the orbiting international Cassini spacecraft suggest the rings have existed as far back as 4.5 billion years ago, roughly the same time the sun and planets formed. The probe also found evidence that ring particles are constantly shattering and regrouping to form new rings.

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A new study of Saturn's striking rings has found clusters of "moonlets," lending support to the theory that large icy moons were slowly pulverized to form the ring system.
The boulder-size chunks, spotted in a narrow belt, could only have been formed when something collided into an object at least as large as Pan, Saturn's innermost moon, which is about 25 kilometres wide, scientists say.

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The rings of Saturn are made of debris left over from dramatic collisions between ancient moons, scientists say.
Analysis of new images of the planet has revealed the presence of boulder-sized bodies in the spectacular rings which researchers believe are left over from the break up of large moons during the last 200 million years.

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The Cassini spacecraft captures eight new propeller-like features within Saturn's A ring in what may be the propeller "hot zone" of Saturn's rings.
Propeller features form around small moonlets that are not massive enough to clear out ring material, but are still able to pull smaller ring particles into a shape reminiscent of an airplane propeller. Scientists believe that propellers represent moonlet wakes, which are denser than the surrounding ring material and appear bright in the images.
Propellers were first discovered in Cassini images taken during Saturn orbit insertion in 2004. This new image is from a more extensive study of the full A ring and provides evidence that these features are not distributed evenly as previously thought, but are instead grouped in a 3,000 kilometre-wide  propeller belt.


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Credit:    NASA/JPL/Space Science Institute/University of Colorado

This image shows four new propellers and was put together from images in the Planetary Data System, a web site which archives and distributes scientific data from NASA planetary missions. The largest propeller seen here is noted in the white dashed box, and it indicates the presence of a 150-meter (490-foot) moonlet. The size is inferred from the radial separation of the propeller wings. The propeller is seen in another image and is shown in the upper left box. The reappearance of the propellers clearly demonstrates the orbital motion of the propellers. The region enclosed in the red box is zoomed and shown in the top panel of Propeller Close Up. Three additional propellers are noted with white dashed circles on the right. Very bright and round spots are artefacts. But some of the bright elongated and non-saturated streaks could be smaller propellers that are not resolved in the image.
This view is made up of two images from a set of 26 images with a complete radial coverage of the A ring and part of the Cassini division taken during an occultation of the star Antares (alpha Scorpii; brightest spot on top) on Aug. 20, 2005. In this clear filter image, the Cassini spacecraft narrow-angle camera observed the unlit side of the rings, with a phase angle of 126 degrees. The images were taken at 1 minute intervals with 0.05 seconds exposure time. Image resolution is 1 kilometre  per pixel.