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.
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.
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 said.