Mimas: Saturn's "Black Death" Moon with a Striking Resemblance to the Death Star

Mimas, one of Saturn's moons, was first observed by William Herschel in 1789. Until the late 20th century, it was merely a bright speck in telescopes, as no instrument was powerful enough to reveal its surface features. The Pioneer 1 mission in 1979 and Voyager 1 in 1980 finally captured close-up images of Mimas, much to astronomers' delight and surprise. They discovered that the moon bore an uncanny resemblance to the Death Star from the 1977 Star Wars film.

While Mimas is not a weapon of mass destruction, its likeness to the Death Star can be attributed to a massive crater on its surface, one of the largest in the entire Solar System. The moon has a diameter of 400 km, and the crater, officially named Herschel, spans 139 km, or roughly one-third of Mimas' diameter. The crater's walls range in height from 5 to 12 km.

For perspective, a comparable crater on Earth would measure over 4,000 km in diameter – larger than Canada – with walls soaring 200 km high. The mystery of how Mimas withstood the impact that created Herschel remains unsolved, as signs of the event are still visible on the moon's surface. On the side opposite the crater, the terrain is notably distorted and jagged, evidence of seismic waves generated during the impact that traversed the entire moon and converged on the other side.

As seen in NASA, JPL, and SSI's images, Mimas' surface is heavily cratered, but none of the other craters come close to Herschel's size. In the northern hemisphere, craters are no larger than 40 km, while those in the southern hemisphere are even smaller, measuring about 20 km in diameter.