The Witch Head Nebula. Located in the Orion Nebula. 1,000 Lightyears away. Neighbor to Rigel, the 7th brightest star in the night sky. The blue glow from this nebula is caused by light reflected from Rigel and the traces of dust grains found in the nebula itself. These dust grains reflect blue light more efficiently than red, similar to how Earth’s atmosphere appears blue through scattered light molecules in addition to the nitrogen and oxygen molecules.