For Cassini's next flyby of Titan on May 12, 2007, the radar instrument was originally pointing north of where it is now pointed. Due to the discovery of probable large seas on Titan, Cassini's quick-thinking team repointed the radar instrument south, so it could fly over a large, expansive dark area dubbed the "Caspian Sea." This flyby will confirm whether it is liquid-filled. This area on Titan's north pole stretches 1,000 kilometers (620 miles) and is only slightly smaller than Earth's Caspian Sea.
The presence of seas on Titan reinforces the idea that Titan's surface must be re-supplying methane to its atmosphere.