Despite the fact we’ve been looking at them for ages, the planets can still spring a surprise or two when you look closely. Today’s surprise is that the cold north pole of Saturn actually hosts a hot ‘cyclone’ (NASA press release).

Scientists had already seen a hot spot at the south pole in 2005; but since it is summer in the southern hemisphere of Saturn (and has been for the best part of a decade) that’s not surprising. The north pole, though, has been in the shade for as long as the south has been in the sun, so the source of its heat is something of a mystery

Leigh Fletcher, co-author of the paper on the new finding in Science, thinks the hot spots are caused by air moving towards the poles, then being compressed and heated as it descends. “The driving forces behind the motion, and indeed the global motion of Saturn’s atmosphere, still need to be understood,” says Fletcher, a planetary scientist from the University of Oxford (Oxford press release).

And the mysteries don’t stop there – there is still no explanation for a strange hexagon feature surrounding the north pole. Although this was first seen back when in the 1980s no-one yet knows why it is there.

Infrared data from Cassini show the hexagon extends higher into the atmosphere than was previously thought. “The mystery is… why on earth — or why on Saturn even — do we see a hexagon around the north pole, and not around the south pole?” Fletcher told SPACE.com.

Cassini is pulling a flyby on Saturn’s moon Titan on the 5th of January. Stay tuned for more strangeness.

Image: NASA/JPL/GSFC/Oxford University