Understanding the past and present history of the galaxy may be within range due to the discovery of an unusual mix of stars. These celestial bodies, which are similar to the Milky Way's ancient stars, can be the key to bridging the investigation.

About 19,000 light years away from Earth, a globular cluster identified as Terzan 5 has been in sight since its detection forty years ago. Now, scientists are taking a second look at this galactic view and decide that it is not merely an ordinary collection of stars.

Based on the data collected from the Advanced Camera for Surveys and the Wide Field Camera 3 on board the NASA/ESA Hubble Space Telescope, Terzan 5 hosts two stars with contrasting elements. It has also been noted that the age gap of these astral bodies is roughly 7 billion years.

Investigations show that the star formation in Terzan 5 has been intermittent. The process is dominated by a couple of distinct bursts that led to the evolution. It is perceived that after the first massive explosion, the celestial body retained the iron-enriched gas to form a new star generation.

Italy's Davide Massari, who co-authors the study, explains that ancestors of the Terzan 5 needs huge amounts of gas that is at least 100 million times the mass of the sun to unravel a second generation of stars.

According to theories on galaxy formation, clusters of stars and gas intertwine to form the primordial bulge of the Milky Way. The process of merging and dissolving happens. Lead author Francesco Ferraro from the University of Bologna notes that some remnants of the clusters remain unperturbed and embedded within the galaxy.  

The study is further strengthened by the fact that the mass of the star cluster is identical to that of Terzan 5. Considering that these celestial bodies manage to exist despite being disrupted at some point makes them the remnants of the Milky Way's historical past.

In line with this, the decrease in mass has also been noted. How galactic fossils survive may be attributed to its rather compact state which allowed it to bounce around and interact with other structures.