Rings and moons 🪐 Saturn's moon Mimas stands alone in this ethereal image captured by our Cassini spacecraft in 2004. Mimas is the smallest of Saturn's major moons, checking in at less than 123 miles (198 km) wide. Its most prominent feature is a massive impact crater, with a small bump in the middle that draws comparisons to the Death Star from Star Wars. Saturn's rings stretch across the bottom of this image, with a small gap near the top known as the Cassini division. (Both this gap and the spacecraft were named after Jean-Dominique Cassini, the first astronomer to discover several of Saturn's moons.) These rings cast shadows on the cool, blue-streaked backdrop of Saturn's northern hemisphere, fading into darkness on Saturn's night side. Image description: Two bands of color arc across this photo of space: a brownish-tan streak across the bottom of the image, and blue-white streaks arcing downward from left to right. A small moon, half in shadow, touches one of the white bands n...