Explanation:
Dark nebulae snake
across a gorgeous expanse of stars in
this
telescopic view toward the
pronounceable constellation
Ophiuchus
and the center of our Milky Way Galaxy.
In fact, the twisting central shape seen here is well known as the
Snake Nebula.
It is also listed as Barnard 72 (B72), one of 182
dark markings of the sky
cataloged in the early 20th century
by astronomer E. E. Barnard.
Unlike bright emission nebulae and star clusters,
Barnard's nebulae
are interstellar dark clouds of obscuring
gas and dust.
Their shapes are visible in
cosmic silhouette
because they lie in the foreground along
the line
of sight to rich star fields
and glowing stellar nurseries near the plane of our Galaxy.
Many of Barnard's dark nebulae are themselves likely sites
of future star formation.
Barnard 72
is about 650 light years away.
With bluish star 44 Ophiuchi at bottom left, the intriguing star
field spans nearly 2 degrees or almost 20 light-years at the estimated
distance of the Snake Nebula.
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