On This Day in Space! Sept. 17, 1789: Saturn’s ‘Death Star’ moon Mimas discovered

On Sept. 17, 1789, the British astronomer William Herschel discovered Saturn’s “Death Star” moon, Mimas. 

Meet Mimas: Saturn’s Death Star Moon

Of course, “Star Wars” wasn’t a thing at the time, and no one had ever heard of something called a “Death Star.” But there’s no denying that this moon looks just like it. 

Saturn’s moon Mimas, as imaged by the Cassini spacecraft, is barely large enough for gravity to pull it into a spherical shape. The vast crater Herschel, which makes Mimas look like the Death Star, is the scar of an impact so large it almost destroyed Mimas!  (Image credit: NASA / JPL-Caltech / Space Science Institute)

Anyway, Herschel was a guy who liked to build telescopes and discover things, like the planet Uranus, tiny moons around Jupiter and Saturn, and other stuff out there in space. Shortly after he invented a huge new kind of reflecting telescope called the Herschelian telescope, he spotted Mimas orbiting Saturn. 

Mimas is super tiny with a diameter of less than 250 miles. It is the smallest known spherical body in space that is held together by self-gravitation.

Catch up on our entire “On This Day In Space” series on YouTube with this playlist. 

On This Day in Space Archive!

Still not enough space? Don’t forget to check out our Space Image of the Day, and on the weekends our Best Space Photos and Top Space News Stories of the week. 

Email Hanneke Weitering at hweitering@space.com or follow her @hannekescience. Follow us @Spacedotcom and on Facebook. 


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