Cassini’s long flight to Saturn meant that it was possible—and important—to make scientific observations with the spacecraft while it was en route. From October 2000 through March 2001, Cassini made an intensive study of Jupiter as it flew by, taking thousands of pictures and making key measurements in conjuction with the Galileo spacecraft. Among its many discoveries, Cassini found persistent weather patterns near Jupiter’s polar regions; and Cassini’s map of Jupiter’s magnetic field showed that Jupiter’s magnetosphere was lopsided, rather than smooth and round, and had several “holes” where electrically charged particles could “leak” through in huge streams.