Let’s be
open about open clusters, or “galactic clusters” if you’d prefer. These
clusters form thousands of stars around the same time out of a single giant
molecular cloud. In our galaxy alone, there are around 1,100 clusters… that we
know of. A mutual gravitational attraction loosely holds the cluster together,
this is not strong enough to prevent other clusters or gas clouds from breaking
off pieces as the cluster moves through space. These clusters last about a few
hundred million years (nothing major). These clusters help up study stellar
evolution, seeing as the stars are all similar age and chemical composition as
opposed to the lone star. Some of these clusters are even big enough as to be seen with
the eye alone.
