Saturn's hexagon is a persistent approximately hexagonal cloud pattern around the north pole of the planet Saturn, located at about 78°N. The sides of the hexagon are about 14,500 km (9,000 mi) long, which is about 2,000 km (1,200 mi) longer than the diameter of Earth. The hexagon may be a bit more than 29,000 km (18,000 mi) wide, may be 300 km (190 mi) high, and may be a jet stream made of atmospheric gases moving at 320 km/h (200 mph). It rotates with a period of 10h 39m 24s, the same period as Saturn's radio emissions from its interior. The hexagon does not shift in longitude like other clouds in the visible atmosphere.
Saturn's hexagon was discovered during the Voyager mission in 1981, and was later revisited by Cassini-Huygens in 2006. During the Cassini mission, the hexagon changed from a mostly blue color to more of a golden color. Saturn's south pole does not have a hexagon, as verified by Hubble observations. It does, however, have a vortex, and there is also a vortex inside the northern hexagon. Multiple hypotheses for the hexagonal cloud pattern have been developed.
Saturn's Strange Hexagon Recreated in the Lab
Saturn boasts one of the solar system's most geometrical features: a giant hexagon encircling its north pole. Though not as famous as Jupiter’s Great Red Spot, Saturn's Hexagon is equally mysterious. Now researchers have recreated this formation in the lab using little more than water and a spinning table—an important first step, experts say, in finally deciphering this cosmic mystery.
Saturn’s striped appearance comes from jet streams that fly east to west through its atmosphere at different latitudes. Most jets form circular bands, but the Voyager spacecraft snapped pictures of an enormous hexagonally shaped one (each side rivals Earth's diameter) when it passed over the planet's north pole in 1988. Stumped scientists first attributed the shape to a huge, stormlike vortex along one of the hexagon’s sides, which Voyager also spotted during its journey. Astronomers believed this gyre was altering the jet stream’s course, much in the same way a large rock would change a nearby river’s path. But when the Cassini mission returned to Saturn and photographed Saturn's north pole in 2006, the vortex was gone, yet the hexagon was still there.
Physicists Ana Claudia Barbosa Aguiar and Peter Read of the University of Oxford in the United Kingdom wanted to see if they could recreate the hexagon in the lab. They placed a 30-liter cylinder of water on a slowly spinning table; the water represented Saturn’s atmosphere spinning with the planet’s rotation. Inside this tank, they placed a small ring that whirled more rapidly than the cylinder. This created a miniature artificial "jet stream" that the researchers tracked with a green dye.
One of those things that just makes you go "what the f*ck..." even when fully properly explained.