Physics Photo of the Week

December 8, 2023 M13 - A Globular Cluster - Photos by Don Collins - College View Observatory There are about 100 of these large clusters of stars orbiting the Milky Way Galaxy.  Similar clusters are found in other galaxies.  These assemblages of stars contain several hundred thousand stars and up to a million stars.  These clusters are also very old - about 10 billion years - older than the Sun and the Solar System.  Unlike open clusters (such as the Pleiades or "Seven Sisters") the globular clusters have so many stars that they are gravitationally stable.  All the stars are whizzing around a common center of mass in random orbits similar to a swarm of insects.  This globular cluster is about 20,000 light years from Earth and about 140 light years in diameter.   If our Solar System were in the midst of this cluster of close to 1 million stars, the sky would be ablaze with starlight!  However, in spite of the incredible age of the cluster, a Solar System would probably not la