Ultraviolet Rings of M31
Image Credit:
GALEX, JPL-Caltech,
NASA
A mere 2.5 million light-years away the Andromeda Galaxy, also
known as M31, really is just next door as large galaxies go.
So close
and spanning
some 260,000 light-years, it took 11 different image fields from the
Galaxy Evolution Explorer (GALEX) satellite's
telescope to produce this gorgeous portrait of the spiral galaxy in
ultraviolet light.
While its spiral arms stand out in
visible light images of Andromeda,
the arms look more like rings in
the
GALEX ultraviolet view,
a view dominated by the energetic light from hot, young, massive stars.
As sites of intense star formation, the rings have been interpreted as
evidence Andromeda collided with its smaller neighboring elliptical
galaxy M32 more than 200 million years ago.
The large Andromeda galaxy
and our own Milky Way are the most massive members of the
local
galaxy group.