For years astronomers have sort to investigate the centre of the galaxy, known as the Milky Way’s “bulge”.
The crowded nature of the galaxy’s centre has previously made it difficult to analyse.
However, new research of around 10,000 Sun-like stars is now thought to have shed light on the unknown past of the bulge.
Annalisa Calamida, from the Space Telescope Science Institute, said: “There are many theories describing the formation of our galaxy and central bulge.
“Some say the bulge formed when the galaxy first formed about 13 billion years ago.
“In this case, all bulge stars should be old and share a similar motion.
“But others think the bulge formed later in the galaxy’s lifetime, slowly evolving after the first generations of stars were born.
“In this scenario, some of the stars in the bulge might be younger, with their chemical composition enriched in heavier elements expelled from the death of previous generations of stars, and they should show a different motion compared to the older stars.”
In an important discovery the new research, based on nine years’ worth of archival data from NASA’s Hubble Space Telescope, has found that aspects of both schools of thought are true.
Ms Calamida added: “This analysis can help us in understanding the bulge’s origin.”
The findings indicate that the bulge is diverse environment of stars with each traveling at different speeds like “travellers bustling about a busy airport”.
The University of Michigan-Dearborn research team found the different motions of each star in the galaxy’s hub can be put down to differences in chemical make-up.
Stars with elements heavier than hydrogen and helium are able to orbit the Milky Way’s centre at a faster rate than older stars where these elements are no longer present.
Ms Calamida explained the initial study from the researchers will hopefully pave the way for more detailed analysis.
She said: “Hubble gave us a narrow, pencil-beam view of the galaxy’s core, but we are seeing thousands more stars than those spotted in earlier studies.
“We next plan to extend our analysis to do additional observations along different sight-lines, which will allow us to make a three-dimensional probe of the rich complexity of the populations in the bulge.”