NASA/JPL/University of Arizona
view of the bizarre weather pattern. The red color indicates
the amount of heat generated in the warm interior of Saturn
that escapes the planet.
One of the most bizarre weather patterns known has
been photographed at Saturn, where astronomers have spotted a huge,
six-sided feature circling the north pole.
Rather than the normally sinuous cloud structures
seen on all planets that have atmospheres, this thing is a hexagon.
The honeycomb-like feature has been seen before.
NASA's Voyager 1 and 2 spacecraft imaged it more than two decades ago.
Now, having spotted it with the Cassini spacecraft, scientists conclude it
is a long-lasting oddity.
"This is a very strange feature, lying in a precise
geometric fashion with six nearly equally straight sides," said Kevin
Baines, atmospheric expert and member of Cassini's visual and infrared
mapping spectrometer team at NASA's Jet Propulsion Laboratory, Pasadena,
Calif. "We've never seen anything like this on any other planet. Indeed,
Saturn's thick atmosphere, where circularly-shaped waves and convective
cells dominate, is perhaps the last place you'd expect to see such a
six-sided geometric figure, yet there it is."
The hexagon is nearly 15,000 miles (25,000
kilometers) across. Nearly four Earths could fit inside it. The thermal
imagery shows the hexagon extends about 60 miles (100 kilometers) down
into the clouds.
At Saturn's south pole, Cassini recently spotted a
freaky human eye-like feature that resembles a hurricane.
"It's amazing to see such striking differences on
opposite ends of Saturn's poles," said Bob Brown, team leader of the
Cassini visual and infrared mapping spectrometer at the University of
Arizona. "At the south pole we have what appears to be a hurricane with a
giant eye, and at the north pole of Saturn we have this geometric feature,
which is completely different."
The hexagon appears to have remained fixed with
Saturn's rotation rate and axis since first glimpsed by Voyager 26 years
ago. The actual rotation rate of Saturn is still uncertain, which means
nobody knows exactly how long the planet's day is.
"Once we understand its dynamical nature, this
long-lived, deep-seated polar hexagon may give us a clue to the true
rotation rate of the deep atmosphere and perhaps the interior," Baines
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