The stars have been discovered near the "bulge" of the galaxy -- its supermassive black hole at the center.
In an amazing new finding, scientists have discovered the oldest stars yet in the Milky Way galaxy, and they show evidence of massive explosions that may have shaped the early history of our galaxy.
Scientists think the first stars formed about 13.6 billion years ago, just 200 million years after the Big Bang set our universe into motion, and these stars are some of the first that could give insight into how our galaxy evolved over the eons, according to a Space.com report.
Scientists still haven’t yet discovered the “first star,” but these ancient stars that are completely depleted of metals heavier than helium and have since died in massive supernovas are probably some of the first successors.
Researchers had expected that such stars would be found in the “bulges” at the center of our galaxy near the supermassive black hole around which everything circles. As a result, scientists hadn’t been able to find any of these “metal-poor” stars because the Earth is in the halo of the Milky Way and nowhere near the bulge. The bulge is a long distance from us and obscured by cosmic dust, making it difficult for scientists to observe.
The formation of stars in our Milky Way galaxy probably happened quite fast because of the density of gas and dust in the bulge, which meant that when these early stars, they only further added heavier elements in the first billion or two years of the universe, making it like finding a “needle in a haystack” for astronomers hoping to witness the metal-poor stars. But scientists think they may have finally done it.
Louise Howes, the study’s lead author from Lund University in Sweden, used the Australian National University’s SkyMapper telescope to examine a large group of stars — 5 million of them, in fact, all located within the bulge of our galaxy. Howes was able to discover 14,000 metal-poor stars, and confirmed that about 500 of them were extremely metal-poor, further narrowing it down to 23 of the most metal-poor to figure out their chemical composition.
It’s a fascinating discovery that could lead to a deeper understanding of our universe and how it evolved.