Star Cluster

Stars are born in groups, or clusters. When there is enough cosmic dust and gas in a cloud in space, its own gravity pulls towards the centre. When the centre gets hot and dense enough stars will form. These are star clusters and they contain a few tens to a few hundred stars.

The stars are all different. Some big, hot and bright. Some, like our Sun, are yellow and moderately hot. Some are cooler and red. These stars all live for different lengths of time, but they are all the same age and all the same distance away from Earth.