One of the brightest galaxies in planet Earth's sky is similar in size
to our Milky
Way Galaxy: big, beautiful M81.
This grand spiral galaxy lies 11.8 million light-years
away toward the northern constellation of the Great
The deep image of the region reveals details in the bright yellow core,
but at the
same time follows fainter features along the galaxy's gorgeous blue
spiral arms and sweeping dust lanes.
It also follows the expansive, arcing feature, known
as Arp's loop, that seems to rise from the galaxy's disk at the upper right.
Studied in the 1960s, Arp's loop has been thought to be a
material pulled out of M81 by gravitational interaction with its large
neighboring galaxy M82.
But a subsequent investigation
demonstrates that at least some of Arp's loop likely lies
within our own galaxy.
The loop's colors in visible and
match the colors of pervasive
clouds of dust, relatively
galactic cirrus only a few hundred light-years above the plane of the Milky Way.
Along with the Milky Way's stars, the dust clouds lie in
the foreground of this remarkable view.
M81's dwarf companion galaxy,
can be seen just above the large spiral.
On the sky, this image spans about 0.5 degrees,
about the size of the Full Moon.
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