Friday, July 2, 1999 Published at 15:47 GMT 16:47 UK
Hubble's swarm of stars
An ancient collection of stars
By BBC News Online Science Editor Dr David Whitehouse
The Hubble Space Telescope has taken this image of a stellar swarm called M80. It is one of the most magnificent of the 147 known globular star clusters that girdle our Milky Way galaxy.
Located about 28,000 light-years from Earth, M80 contains hundreds of thousands of stars.
Globular clusters are ancient structures. They swarm around our galaxy in a shell that indicates that they were there long before our galaxy took its flattened shape.
They are particularly useful for studying stellar evolution. This is because all of the stars in the cluster have the same age (about 15 billion years), but cover a range of stellar masses.
Every star in this image is either older, or in a few rare cases more massive, than our own Sun. Especially noticeable are the bright red giants, stars like our Sun that are nearing the ends of their lives.
Astronomers have found a large number of so-called "blue stragglers" in the core of the cluster.
These appear to be unusually young and more massive than the other stars. It is believed that they are formed when two older stars collide forming a new rejuvenated star.
Based on the number of blue stragglers, the stellar collision rate in the core of M80 appears to be exceptionally high.