Saturn's Dancing Moons

I was away at the NSTA meeting in New Orleans and hadn't managed to post for a few days. I get back today and find that the Cassini Team has relased some spectacular images and movies of Saturn's Moon's casting shadows on the rings!

Saturn is nearing its equinox later this year. Near the equinox is the only time you can see moon shadows cast on Saturn's rings and we have NEVER had a spacecraft at Saturn to capture these images before! This image shows Saturn's moonEpimetheus as its shadow moved across the rings over the course of about an hour.

Since the rings are almost edge on to the Sun, the shadows cast by the Moons are very long. If you could stand on a particle in the rings, the Sun would be very low in the sky right now. Shadows grow long. You can do this yourself here on Earth. Take a large ball outside a few minutes before sunset. Hold it up and look at its shadow. You will see the shadow of the ball is not round, but long and thin. We are seeing an extreme case of this phenomena here.

We knew this should happen based on the geometry for many years. Now we finally get to see it!

Reprinted with permission from the Half-Astrophysicst Blog.