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  • Music of the Spheres
    Posted by Frank Morring, Jr. 5:37 PM on Apr 27, 2011

    The Cassini probe is the gift that keeps on giving.

    The hardy spacecraft has discovered an electrical link between giant Saturn and its tiny frozen moon Enceladus, which feeds Saturn's rings a steady diet of water-ice particles from some geysers near its south pole that erupt from a series of cracks -- also discovered by Cassini -- called the Tiger Stripes.

    blog post photo

    It turns out Enceladus is at one end of a magnetic field line that runs 150,000 miles to the north pole of the planet. Using the spacecraft's fields and particles instruments, researchers found an ultraviolet glow near Saturn's north pole that is known as an auroral footprint, apparently triggered by energetic protons that originate at the active moon and follow the magnetic field line to the planet's upper atmosphere. The connection had been predicted, but it was only confirmed when Cassini's instruments spotted the California-sized glowing patch highlighted in white boxes in these images from the probe's ultraviolet imaging spectrograph.

    blog post photo
    NASA/JPL/University of Colorado/Central Arizona College

    Click here to see a short video illustrating the connection

    "We were delighted to find the glow close to the bulls-eye at the center of our target," stated Wayne Pryor of Central Arizona College, a lead author of a paper on the phenomenon published in the journal Nature.

    Scientists believe the cloud of water molecules from the Tiger Stripes produces an ionized cloud that disturbs the planet's magnetic field lines. Flickering observed in the auroral footprint suggests that the rate of venting through the geysers varies, possibly answering another question.

    "The new data are adding fuel to the fire of some long-standing debates about this active little moon," states Abigail Rymer of the Johns Hopkins University Applied Physics Laboratory and another lead author of the Nature paper. "Scientists have been wondering whether the venting rate is variable, and these new data suggest that it is."

    Among the Cassini data on the Enceladus-Saturn link is a hissing noise in radio wavelengths detected by a team that published its results in Geophysical Research Letters. Click here to hear the sound of Enceladus' magnetic connection with Saturn, altered to be audible to human ears, and see a graph representing the intensity of the electron flow.

    Tags: os99, Cassini, Saturn, Enceladus, electric link

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