* Astronomy

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RE: Saturn

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This image was taken with the Cassini spacecraft wide-angle camera using a combination of spectral filters sensitive to wavelengths of infrared light centred at 728 (green channel), 752 (red channel), and 890 (blue channel) nanometers. The semi-transparent red features across the image are clouds detected by the 752 nanometer filter.

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Credit: NASA/JPL/Space Science Institute

The view was acquired on Aug. 19, 2005 at a distance of approximately 492,000 kilometres from Saturn. Image scale is 26 kilometres per pixel.

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Southern view of Saturn

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RE: Saturn

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Saturno

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RE: Saturn

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Geometric whirlpools revealed
Bizarre geometric shapes that appear at the centre of swirling vortices in planetary atmospheres might be explained by a simple experiment with a bucket of water.
Researchers at the Technical University of Denmark in Lyngby have created similar geometric shapes (holes in the form of stars, squares, pentagons and hexagons) in whirlpools of water in a cylindrical bucket1. The shapes appear easily enough once the bucket is spinning at a rate of one to seven revolutions per second, they say.

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An odd, six-sided, honeycomb-shaped feature circling the entire north pole of Saturn has captured the interest of scientists with NASA's Cassini mission.
NASA's Voyager 1 and 2 spacecraft imaged the feature over two decades ago. The fact that it has appeared in Cassini images indicates that it is a long-lived feature. A second hexagon, significantly darker than the brighter historical feature, is also visible in the Cassini pictures. The spacecraft's visual and infrared mapping spectrometer is the first instrument to capture the entire hexagon feature in one image.

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Credit NASA

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Secrets surrounding Saturn
In the cold outer reaches of our solar system lies a planet that has entranced astronomers since Galileo first saw it through a telescope in 1610 - Saturn.
It is surely the most beautiful, alien and enigmatic of the planets - its squashed sphere and plane of rings has become an icon for space itself. It lies a long way out, twice as far from Earth as Jupiter and nearly one-and-a-half billion kilometres from the sun. In the sky at night, seen without a telescope, it is a large, steady yellowish point.

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In a David and Goliath story of Saturnian proportions, the little moon Enceladus is weighing down giant Saturn's magnetic field so much that the field is rotating slower than the planet. This phenomenon makes it nearly impossible to measure the length of the Saturn day using techniques that work at the other giant planets.

"No one could have predicted that the little moon Enceladus would have such an influence on the radio technique that has been used for years to determine the length of the Saturn day" - Dr. Don Gurnett of the University of Iowa, Iowa City. Gurnett is the principal investigator on the radio and plasma wave science experiment onboard NASA's Cassini spacecraft.

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Credit: NASA/JPL

The radio technique measures the rotation of the planet by taking its radio pulse rate -- the rhythm of natural radio signals from the planet.
A new study of Cassini data reported this week in the online version of the journal Science determined that Saturn's magnetic field lines, invisible lines originating from the interior of a magnetized planet, are being forced to slip relative to the rotation of the planet by the weight of electrically charged particles originating from geysers spewing water vapour and ice from Enceladus. These results are based on joint observations by two Cassini instruments-the radio and plasma wave instrument and the magnetometer.

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