Milky Way’s Disk Appears to Have Formed in Reverse, With Younger Stars Settling Into Thinner Layers
A new analysis of Milky Way star formation suggests the galaxy’s disk did not simply flatten over time in a single, orderly process. Instead, the oldest stars appear to have formed in a thick, turbulent disk, while younger generations emerged later in progressively thinner layers, offering a new timeline for how spiral galaxies mature. The findings sharpen astronomers’ understanding of the Milky Way’s early dynamics and the role of gas settling, turbulence and chemical evolution in shaping a galaxy like our own.
