The Cassini-Huygens probe flew by in February , 2007 , taking radar and camera pictures of some large areas near the north pole that may be large areas of liquid methane and\/or ethane , including one sea larger than 100,000 kmÂ ( larger than Lake Superior ) , and another area similar in size to the Caspian Sea . During a Cassini flyby in late February 2007 , radar and camera observations revealed several large features in the north polar region that may be large expanses of liquid methane and\/or ethane , including one sea with an area of over 100,000 kmÂ ( larger than Lake Superior ) , and another ( though less definite ) region potentially the size of the Caspian Sea .