Because it’s beautiful.
For a wonderful and informative discussion of this image of Saturn and its moon, visit Bad Astronomy, and as Phil Plait so eloquently reminds us towards the end of his post,
…in science, there’s no such thing as just a pretty picture. Science is a tapestry, a vast complex fabric interwoven with countless threads. Each of those threads is amazing, each important, and each leads to another. And that’s where the true beauty of science lies.
Photo originally found here.