In this unusual image of the planet Saturn, the shadow of the planet can be seen falling across the delicate rings. This global view of the planet was created from 45 smaller images taken by NASA's Cassini spacecraft. The shadow of the rings can also been seen on the planet's clouds on the left side of the image. The complexity of Saturn's rings can easily be seen here. The rings are composed almost entirely of water ice particles. These particles range in size from grains of dust to the size of a large bus. They are less than 2 miles (3.2 kilometers) in thickness.