The Snake Nebula in Ophiuchus.

What slithers there? The dark winding lanes visible in part of the constellation Ophiuchus belong to the Snake Nebula. The Snake Nebula is a series of dark absorption clouds made up of Interstellar dust . Interstellar dust grains - composed predominantly of carbon - absorb visible starlight and reradiate much of it in the infrared . This absorption causes stars behind the clouds to be obscured from view, hence the appearance of starless voids on the sky.