Parts of the Milky Way Are , Older Than Previously Thought, Study Reveals.<br />Space.com reports that the Milky Way is often viewed as being made up of two major parts:.<br />the thin disk, where the solar system and much of what we know as the Milky Way resides, and the <br />thick disk, which is larger and more sparse.<br />A new study, conducted by astronomers from the Max-Planck Institute for Astronomy in Heidelberg, Germany, .<br />has found that the thick disk appears to be about 2 billion years older than previously thought.<br />It's likely that the thick disk formed just 800 million years after the Big Bang.<br />For the study, the team examined the Milky Way's sub-giants, which are stars existing in the stage between regular stellar life and the red giant phase.<br />Since a star is only ever a sub-giant for a <br />few million years, astronomers are able to more accurately determine its age.<br />The ages of 250,000 sub-giants were discovered as part of the study by using data from China's Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) and the European Space Agency's (ESA) Gaia mission.<br />The researchers deduced that most of the <br />Milky Way's star formation occurred in two waves.<br />The first wave has to do with the <br />thick disk and took place 13 billion years ago.<br />Then, the Milky Way collided with another galaxy, Gaia-Sausage-Enceladus, resulting in the thin disk about 6 billion years later.<br />Since the discovery of the ancient merger with Gaia-Sausage-Enceladus, in 2018, astronomers have suspected that the Milky Way was already there…but we didn’t have a clear picture of what that Milky Way <br />looked like, Maosheng Xiang, an astronomer at the Max Planck Institute for Astronomy and one of the paper's authors, via statement published by the ESA
