NASA has released a new Hubble Space Telescope image showing more than 500,000 stars in the globular cluster Messier 3. The portrait was shared to mark the United States' 250th anniversary.
The image highlights one of the Milky Way's largest globular clusters, located far from the galactic center. Messier 3 contains over 240 RR Lyrae variable stars, more than any other known cluster, which help astronomers measure distances accurately.
It also includes around 70 blue straggler candidates, stars that appear younger due to material pulled from companions. Scientists suggest the cluster may have formed from the merger of two clusters originating in a dwarf galaxy absorbed by the Milky Way long ago.
Hubble has observed Messier 3 multiple times as part of a Treasury program surveying about half of the galaxy's known globular clusters. The colors in the image represent different wavelengths, with blue indicating hotter stars and red cooler ones.