This illustration shows the disk of our Milky Way galaxy, surrounded by a faint halo of old stars. Hubble Space Telescope measurements of 13 halo stars' motion indicate the possible presence of a shell in the halo, which may have formed from the accretion of a dwarf galaxy.
The Milky Way's far outer reaches may harbor a shell of stars left over from a long-ago act of galactic cannibalism, a new study suggests.
The finding supports the idea that our Milky Way has continued to grow over the eons by gobbling up smaller satellite galaxies, researchers said. And the results may help astronomers better understand how mass is distributed throughout the galaxy, which could shed light on the mysterious dark matter that's thought to make up more than 80 percent of all matter in the universe.
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