Saturn is large and bright enough to have caught the eye of early astronomers. In the ninth century, Al-Farghani, an Arabic astronomer, estimated the distance to Saturn at 133 million kilometers. We know today it is over ten times further. Galileo, the first scientist to use a telescope for astronomical observa- tion, discovered the planetΓÇÖs ring structure in 1610, although it was another 40 years before Christiaan Huygens clearly identified them. In 1675 Giovanni Cassini identified the large gap that appears to divide the ring into two parts, and today the ΓÇ£Cassini DivisionΓÇ¥ bears his name. Initially, scientists thought the rings were solid, but then realized that, if solid or liquid, they would break apart. In 1856 the Scottish astronomer James Clerk
