Great Hercules Globular Cluster

There are over 150 Globular Star Clusters found inside the Milky Way Galaxy.  Larger galaxies can have even more, with Andromeda Galaxy containing more than 500, and Galaxy Messier 87 a staggering 13,000.  These star clusters contain hundreds of thousands of densely packed stars and form a spherical cluster due to the gravitational relationship with one another.  Little is known about Globular Clusters with relation to how they were formed.  There is debate over whether the stars were all formed at the same time, or whether stars were acquired somehow over many generations of stars and hundreds of millions of years.  The theories on formation even change from one star cluster to another, but similarities can be drawn between them.  Most contain older yellow stars and very few young hot stars, which suggest that (more…)