Saturn hurricane snapped by Cassini craft

BBC News online - 30 April 2013

In the image, red indicates clouds at lower altitudes, with green representing higher altitude

An enormous hurricane raging at Saturn's north pole has an eye 2,000km (1,250mi) across - big enough to cover the UK 12 times over.

The striking images of the storm were snapped from a height of 420.000km (260,000mi) by the Cassini spacecraft, which arrived at Saturn in 2004.

They were captured in red and infrared wavelengths and have been false-coloured to show detail.
Scientists say the hurricane's winds reach a staggering 150m/s (330mph).
But they do not know just how long the storm has been brewing.

When Cassini first arrived, the north pole was in darkness; it was winter in the planet's 29-Earth-year annual cycle.

Now it has taken some of its first sunlit images of the pole, which has not been seen since the Voyager 2 craft last sent pictures on its fly-by in 1981.

Andrew Ingersoll, a member of the Cassini team based at the California Institute of Technology in California, US, said: "We did a double take when we saw this vortex because it looks so much like a hurricane on Earth."

"But there it is at Saturn, on a much larger scale, and it is somehow getting by on the small amounts of water vapour in Saturn's hydrogen atmosphere."

The team believes the hurricane to be "stuck" at the pole, forced northward by winds in the same way hurricanes tend to move north on Earth.

Cassini caught sight of an even larger storm in 2006 - the first time a hurricane had been seen on another planet.