 This stellar system resembles a globular cluster, but it's like no other cluster known. A team of astronomers found that there are two distinct kinds of stars in Terzan 5, which not only differ in the elements they contain, but also have an age gap of roughly 7 billion years. The ages of the two populations indicate that the star formation process was not continuous, but was dominated by two distinct bursts of star formation, while the properties of Terzan 5 are uncommon for a globular cluster. They are very similar to the stellar populations which can be found in the galactic bulge. These similarities could make Terzan 5 a relic of a galaxy formation representing one of the earliest building blocks of the Milky Way.