Milky Way grew by cannibalizing other smaller galaxies

NASA’s Hubble Space Telescope peered deep into the vast stellar halo that envelops our Milky Way galaxy and uncovered tantalizing evidence for the possible existence of a shell of stars that are a relic of cannibalism by our Milky Way.

Hubble was used to precisely measure, for the first time ever, the sideways motions of a small sample of stars located far from the galaxy’s center. Their unusual lateral motion is circumstantial evidence that the stars may be the remnants of a shredded galaxy that was gravitationally ripped apart by the Milky Way billions of years ago.

These stars support the idea that the Milky Way grew, in part, through the accretion of smaller galaxies