Among its other attractions, the Milky Way is peppered with about 150 globular clusters: round concentrations of stars that have existed since the galaxy was young.
This sculpture is a many-body simulation tuned to match M13, a famous cluster in Hercules. Among its stars there's a sprinkle of larger points representing red giants and horizontal branch stars, showing their concentration near the cluster's center.
In 1974, M13 was selected as a target for one of the first radio messages addressed to possible extra-terrestrial beings, sent by the Arecibo radio telescope. If anyone is there when it arrives 26,000 years from now, they are living under a skyful of stars as bright as our moon.
Laser etched glass