M67 (NGC 2682) -- Open Cluster in Cancer
The open cluster M67 is interesting because of its age. Stars are born from large
gas/dust clouds and, more often than not, as large clusters of stars. The gravitational
vulgarities within the newly formed star cluster usually disperses the stars over time
(our sun was born in a cluster that has long since dispersed). But M67 formed so
dense (so many stars close together) that it has held together for the past 4 to 5 billion
years. Ancient for an open cluster.