At one point in its tour, the Cassini space probe went behind Saturn, so the sun was covered up. The sun was also behind the rings, so we are seeing them shine from within. In this view, you can see the faint and misty G and E rings. Also, there is a bright speck on the left, just inside the G ring. That is not a moon, but Earth in the background!
Credit: NASA/JPL/Space Science Institute