Saturn's Seasonal Sundial
Saturn's Seasonal Sundial
This Demonstration simulates the seasonal shift of the shadows cast by Saturn's rings on the planet's surface.
As a result of its axial tilt of 26.75°, the shadows of Saturn's rings move up and down its surface as the planet makes its way around the sun in approximately 29.5 Earth years. The position of these shadows marks Saturn's seasons in its orbit around the sun, just like the shadow of the style on a sundial indicates the time of day on Earth.
These shadows are not easily visible from Earth because, from our vantage point near the Sun, the rings block their shadows. However, the Cassini robotic spacecraft, currently orbiting Saturn, made some remarkable images of these shadows.
In this Demonstration, the viewpoint is taken to be tangential to the orbit of Saturn (similar to Cassini), in order to get a good view of the ring shadows.