Our Galaxy's oldest open clusters
For these star clusters, distance is the key to longevity.
For open clusters, wandering throughout the Milky Way can be a risky venture. Their survival requires a little bit of luck and a lot of distance from the inner region of the Galaxy. Only a handful of clusters have endured as long as M67. The average life span of an open cluster is just a few hundred million years, but veterans like M67 have been touring the Milky Way since before our Sun first shone. These clusters are as lucky as they are mysterious. Images and details abound for younger, brigh...