Mimas

The moon that looks like the Death Star

Mimas is a small icy moon of Saturn with one giant crater. The crater is so big that Mimas looks like the Death Star from Star Wars! The crater is named Herschel, after the scientist who discovered Mimas in 1789. Had the impact been a little stronger, Mimas would have shattered.

Mimas (radius 198 km) is one of the smallest known bodies rounded by its own gravity. It is the closest major moon to Saturn (185,500 km), orbiting every 22.6 hours. Herschel crater is 130 km wide — a third of Mimas's diameter; its walls are 5 km high and its central peak 6 km. The impact fractured the opposite side. Mimas's gravity carves the Cassini Division in Saturn's rings (orbital resonance). In 2024, analysis of Cassini data gave a surprise: beneath 20–30 km of ice, Mimas hides a young (under 25 million years) liquid ocean.

Fun facts

• If Herschel crater were on Earth, it would stretch from Tashkent to Samarkand.
• Mimas scrapes a gap in Saturn's rings — like a fingernail through sand.
• Mimas was discovered in 1789, but Voyager first saw its face only in 1980.