Milky Way's disk grew 'upside down,' with younger stars forming in ever-thinner layers

The Milky Way is home to hundreds of billions of stars arranged in a glorious spiral pattern. But beyond the obvious spiral, our galaxy has other physical characteristics. It's divided into a galactic bulge, a galactic disk and a galactic halo. This story matters for Science & Discovery readers tracking mech. Reported by phys.org. Read the full original at the source link below.