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 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 is located at 20 light-years at the estimated distance of the Snake Nebula
[Text adapted from APOD]