On this day in space! Sept. 17, 1789: Astronomer William Herschel discovers Saturn's 'Death Star' moon Mimas

While Mimas was discovered today in 1789, it wasn't until 1980 that we learned of its Death Star shape. [Read Full Story on Space.com →](https://www.space.com/space-exploration/on-this-day-in-space-september-17-2026)