Explanation:
What is the Andromeda galaxy really like?
To find out, astronomers looked at our
largest galactic neighbor
in a different light: infrared.
Astronomers trained the orbiting
Spitzer Space Telescope at the
Messier monster (M31) for over 18 hours,
creating a mosaic that incorporated 11,000 separate exposures.
The result, pictured above, shows M31 in greater infrared detail than ever before.
Infrared light in this 24-micron color band is particularly sensitive to
dust heated up by stars.
Visible above are
previously undiscovered features including intricate structure in the spiral arms,
a spiral arc near the center, an off center ring of star formation,
and an unusual hole in the galaxy's disk.
In contrast, the Andromeda galaxy appears much
smoother in visible light and even
ultraviolet light.
Analyses and comparison of this image to other images will likely yield
clues not only to the violent past of
M31 but to our own
Milky Way Galaxy as well.
