It's a galaxy-eat-galaxy world out there. A new study of the Andromeda galaxy, the closest neighbor to our own Milky Way at 2.5 million light years away, has mapped Andromeda in unprecedented detail and found evidence that it grew through devouring smaller galaxies.
Stars and dwarf galaxies that got too close to Andromeda were ripped from their usual surroundings. "What we're seeing right now are the signs of cannibalism," said study lead author Alan McConnachie.... "We're finding things that have been destroyed ... partly digested remains" [AP].
Astronomers had already posited the "hierarchical model" in which small galaxies combine to form large ones, but the new study shows the model in action. The map shows
stars in bright streams and clumps that were also likely ripped from dwarf galaxies that once orbited Andromeda [New Scientist].
Researchers say the clumps of stars around the edge of Andromeda couldn't have formed there, ...
