Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2003 March 19 Jupiter's Great Dark Spot Credit: Cassini Imaging Team, Cassini Project, NASA Explanation: Seventeenth century astronomer Giovanni Domenico Cassini was an astute observer of Jupiter's Great Red Spot. So it seems only fitting that his namesake, the Cassini spacecraft, has enabled detailed observations of another planet-sized blemish -- Jupiter's Great Dark Spot. Unlike the Red Spot, the Great Dark Spot lies near Jupiter's north pole and...