The Milky Way Once
Had a Sister Galaxy, but Andromeda Ate It University of Michigan scientists
have discovered that we once had a sister
galaxy that was consumed by the Andromeda
galaxy about two billion years ago. Scientists have long thought that
the halo of stars surrounding Andromeda
indicated that the large galaxy most likely
ate smaller surrounding galaxies. However, there was never
really a way to figure out
just how many galaxies
it had consumed. Through the use of computer modeling, researchers are finding that most of Andromeda's
outer halo of stars was most
likely made from one larger galaxy. Enter our sister galaxy, M32p. This galaxy was third in size to Andromeda
and the Milky Way. Eric Bell, co-author of paper in 'Nature Astronomy' This discovery also helps to shed light
on Andromeda's small satellite galaxy, M32.
Scientists have never been able
to figure out where it came from. Under the theory of Andromeda eating a sister galaxy, they can extrapolate that it originated
as a remnant of M32p. Side note: Our galaxy will collide with Andromeda as well. But don't stress too much.
It's destined to arrive in four billion years.