Spacecraft Cassini Enters Saturn's Orbit (AP). AP - The international Cassini spacecraft threaded a gap between two of Saturn's dazzling rings late Wednesday and entered orbit around the giant planet, completing one of the mission's most critical maneuvers more than 900 million miles from Earth. [Yahoo! News - Reader Ratings]

Over the next four years I'm looking forward to many exciting discoveries from the Cassini probe.  Cassini has already made observations that indicate to scientists that Saturn's moon Phoebe is an ancient object formed at the beginning of the solar system like the Kuiper Belt objects, but, unlike them, Phoebe was captured by Saturn's gravity rather than being swept out past the orbit of Pluto. Latest findings also reveal that the rotation of Saturn may be highly variable. Of course, I've always wondered how scientists could pin down the rotation period of a tiny ball of liquid hydrogen nested deep within a gigantic ball of gas.

Saturn's moon Titan will get some special attention as Cassini will release the Huygens lander to take data from the surface. Scientists believe that the conditions on Titan represent those of the Earth of four and a half billion years ago.