miranda

Like Frankenstein's monster, Miranda looks like it was pieced together from parts that didn't quite merge properly. At about 500 km in diameter, it's only one-seventh as large as Earth's moon, a size that seems unlikely to support much tectonic activity.

Yet Miranda sports one of the strangest and most varied landscapes among extraterrestrial bodies, including three large features known as "coronae," which are unique among known objects in our solar system. They are lightly cratered collections of ridges and valleys, separated from the more heavily cratered (and presumably older) terrain by sharp boundaries like mismatched patches on a moth-eaten coat. Miranda's giant fault canyons are as much as 12 times as deep as the Grand Canyon. Due to Miranda's low gravity and large cliffs, a rock dropped off the edge of the highest cliff would take a full 10 minutes to reach the foot of the cliff.