Marsh 144 p. 167).
800 years later, Andromeda became
the 31st entry
in Charles Messier’s
"Catalogue of Nebulae and Star Clusters".
From “a small cloud” to “nebula” and now known to be
our nearest major galaxy,
Andromeda has remained a fundamental astronomical object.
Today’s image,
taken over 202 hours, shows how far we have come in our ability to observe our neighbor.
The diffuse red and blue clouds
are mostly foreground ionized hydrogen and oxygen well within our
Milky Way.
Pink-red clouds of hydrogen
ionized
by the energetic light of young stars trace the galaxy’s
dusty spiral arms.
M32 and
M110
are
satellite galaxies
pictured orbiting the larger Andromeda. Despite its long history of observation through ancient unaided eyes to modern telescopes, Andromeda still holds countless secrets that
astronomers will continue to search for, including how galaxies
merge and evolve,
as well as the nature of the
dark matter
that galaxies reside in.