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
Boy with a Glass and a Lute hand a glass full of wine, at which he looks with a smile. His dark costume is trimmed with blue ; his cap hangs on the back of his head, to the left. With his left hand he holds up one end of a mandoline, the other end of which rests on a table. Signed on the right with the monogram ; panel, 36 inches by 30 inches. Exhibited at the Royal Academy Winter Exhibition, London, 1891, No. 72." Hals' positioning of a figure looking upwards was common to many of his genre paintings of the 1620s: This painting is