Saturn is Glowing

A mystery glows on Saturn

by Alan Boyle msnbc

Scientists say the northern lights on Saturn are unlike anything they've ever seen, on Earth or elsewhere in the solar system. Infrared imagery from the Cassini orbiter, released today to accompany research published in the journal Nature, only adds to the mystery at the top of the ringed planet.

Saturn's north pole is already home to a bizarre six-sided cyclone that planetary scientists haven't yet figured out. That observation marked the first time a hexagon had been seen in atmospheric patterns. The northern auroral displays, monitored by Cassini's visual and infrared mapping spectrometer, also go against the conventional wisdom.

On Earth and Jupiter, for instance, astronomers are used to seeing auroral arcs or rings of light - which glow when energetic particles stream along a planet's magnetic field and interact with the atmosphere. The auroras on Earth, also known as the northern or southern lights, are sparked by the solar wind. Jupiter's main auroral ring is powered by the planet's own magnetic processes.

Saturn's main auroral ring, like Earth's, is caused by the solar wind. But the newly observed infrared displays go all over the place.

"We've never seen an aurora like this elsewhere," the University of Leicester's Tom Stallard, lead author of the Nature paper, said today in a NASA news release. "It's not just a ring of aurorae like those we've seen at Jupiter or Earth. This one covers an enormous area across the pole. Our current ideas on what forms Saturn's aurorae predict that this region should be empty, so finding such a bright one here is a fantastic surprise."

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