Rigel is located about one photo-width off the image to the right. Fine dust in the nebula reflects the light. The blue color is caused not only by Rigel's blue color but because the dust grains reflect blue light more efficiently than red. The same physical process causes Earth's daytime sky to appear blue , although the scatterers here are molecules of nitrogen and oxygen . The nebula lies about 1000 light-years away.
Reflection nebulae reflect light from a nearby star.
Many small carbon grains in the nebula reflect the light. The blue color typical of reflection nebula is caused by blue light being more efficiently scattered by the carbon dust than red light. The Pleiades nebulosity is caused by a chance encounter between an open cluster of stars and a molecular cloud . The Pleiades can be seen without binoculars from even the depths of a light-polluted city . The Pleiades contains over 3000 stars, is about 400 light years away, and only 13 light years across.