APOD 1.8

http://apod.nasa.gov/apod/ap091229.html

Rigel and the Witch Head Nebula (Dec. 29 2009)

I found this nebula to be interesting and whimsical because like its name, the Witch Head Nebula, it really does look like a witches' head. It is a reflection nebula which are clouds of dust that are simply reflecting the light of a near by star, in this case, the star is Rigel. Rigel is the brightest star in the constellation Orion and the sixth brightest star in the sky. Fine dust in the nebula reflects the light. Pictured above, the blue color of the Witch Head Nebula and of the dust surrounding Rigel 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 in Earth's atmosphere are molecules of nitrogen and oxygen. Rigel, the Witch Head Nebula, and gas and dust that surrounds them lie about 800 light-years away. The Witch Head Nebula is also known as IC 2118.