Mean diameter: approximately 1,523 km · Orbits Uranus.
Uranus’s second-largest moon opens the countdown. Voyager 2 revealed a surface crowded with impact craters during its January 1986 flyby. Unlike a smooth, recently resurfaced world, Oberon preserves abundant visible scars from collisions.
Look for bright rays around some craters in the image. Its battered face offers a useful contrast with Titania, the larger Uranian moon coming next in this list.
Sources: NASA moon guide · JPL size data.
Image source: NASA/JPL; reuse terms. Resized and JPEG-compressed.