Saturn and Two Moons: Dione and Titan
You know….NASA’s Cassini spacecraft has taken some pretty amazing pictures, but this has to be one of the best. This image, released on December 22, 2011 shows Saturn’s largest moon, Titan, almost eclipsing Saturn’s fourth-largest moon, Dione. Fantastic!
There’s a lot going on in this image, so I want you to check it out closely. One of the first things you notice is massive, bronze colored Titan in the center. Titan is 3,200 miles or 5,150 kilometers across. Titan is big enough to have an atmosphere and you can see evidence of this as a slight haze surrounding it.
Smaller Dione is much lighter in color and appears to be bumping into Titan. In reality, Dione lies about 600,000 miles away from Titan. Dione is composed primarily of water ice, which is probably what explains it’s icy, white color.
What do you think is causing those darker colored horizontal bands in the image? Why those are Saturn’s rings of course! Cassini was looking at the northern and sunlit side of the rings and was just above the ring plane.
The Cassini spacecraft took this picture on May 21, 2011 and just happened to be in the right place at the right time to capture these two moons in the same camera frame. Believe it or not, Cassini was about 1.4 million miles away from Titan and 2.0 million miles away from Dione when the image was taken.
Credit: NASA/JPL-Caltech/Space Science Institute