Saturn's hexagon change in season. These changes were observed by the Cassini spacecraft. One hypothesis, developed at Oxford University, is that the hexagon forms where there is a steep latitudinal gradient in the speed of the atmospheric winds in Saturn's atmosphere. Similar regular shapes were created in the laboratory when a circular tank of liquid was rotated at different speeds at its centre and periphery. The most common shape was six sided, but shapes with three to eight sides were also produced. The shapes form in an area of turbulent flow between the two different rotating fluid bodies with dissimilar speeds. A
A Plane Is Born Mark visits the Popular Flying Association Rally at Cranfield to see some of the 3000 or so home-built and vintage aircraft that have flown in for the weekend. He talks to Graham Newby, the Chairman of the PFA and the Editor of Flyer Magazine who takes him through the perils and pit falls of building his own plane. - Test Flight Mark travels to the Europa Factory in North Yorkshire where after seeing all the components that go into making a kit, he takes a test flight with Technical Director Andy Draper. In part 2, he starts his private pilot