Herschel's
Andromeda
From NASA’s Astronomy Picture of the Day
This infrared view from
the Herschel Space Observatory explores the Andromeda Galaxy, the closest
large spiral galaxy to our own Milky Way. Only 2.5 million light-years distant,
the famous island universe is also known to astronomers as M31.
Andromeda spans over 200,000 light-years making it more the twice the size
of the Milky Way. Shown in false color, the image data reveal the cool dust lanes and clouds that
still shine in the infrared but are otherwise dark and opaque at
visual wavelengths.
Red hues near the
galaxy's outskirts represent the glow of dust heated by starlight to a few tens
of degrees above absolute zero. Blue colors correspond to hotter dust warmed by
stars in the more crowded central core.
Also a tracer of molecular gas, the dust highlights Andromeda's prodigious
reservoir of raw material for future star formation.
Image Credit: ESA/Herschel/PACS & SPIRE Consortium, O. Krause, HSC, H. Linz