When NASA’s Cassini spacecraft arrived at Saturn in 2004, the gas giant’s southern hemisphere was enjoying summertime, while the northern was in the midst of winter. Cassini spied a broad, warm, high-altitude vortex at Saturn’s southern pole, but none at the northern pole. A study led by the University of Leicester has now spotted the first glimpses of a northern polar vortex forming high in the atmosphere as Saturn’s northern hemisphere approached...