Star cluster · M1325,000 light-years away
Hercules Globular Cluster
The Hercules Globular Cluster (M13) is a glittering ball of over 100,000 ancient stars packed into a sphere roughly 145 light-years across, making it the brightest and most famous globular cluster in the northern sky. Easily spotted with binoculars in the constellation Hercules, it also earned a place in history in 1974 as the target of the Arecibo Message, humanity's first deliberate radio broadcast aimed at possible extraterrestrial civilizations.
