Saturn's rings form a cosmic sundial

The latest awesome image from the Cassini orbiter gives us an unusually rotated view of the rings around Saturn. They essential form the largest sundial in the known universe, revealing Saturn's seasons, just like Earth sundials tell the time.

At its most basic, a sundial is simply something that uses the position of the Sun to measure time. To make a sundial, you need a sharp edge, or style, which casts different shadows on the surface depending on what time it is. In this case, Saturn's rings work much like a style on an Earth sundial, forming the sharp edge that casts different shadows onto the surface of the gas giant. Of course, you can't tell the hour with this sundial, as we're working on a larger scale. Instead, the shadows cast by the rings reveal the different seasons.

A NASA astronomer explains how this particular cosmic sundial works:

In 2009, during Saturn's last equinox, Saturn's thin rings threw almost no shadows onto Saturn, since the ring plane pointed directly toward the Sun. As Saturn continued in its orbit around the Sun, however, the ring shadows become increasingly wider and cast further south. These shadows are not easily visible from the Earth because from our vantage point near the Sun, the rings always block the shadows. The above image was taken in August by the robotic Cassini spacecraft currently orbiting Saturn. The rings themselves appear as a vertical bar on the image right. The Sun, far to the upper right, shines through the rings and casts captivatingly complex shadows on south Saturn, on the image left.

Via NASA.