Observing the Witch Head Nebula
NASA's Astronomy Picture of the Day features the Witch Head Nebula, a glowing blue cloud of gas and dust in the constellation Orion.
According to NASA's Astronomy Picture of the Day, the Witch Head Nebula, known scientifically as IC 2118, earned its name from its appearance, which resembles a caricature of a witch's head. The nebula spans about 50 light-years and consists of gas and dust being eroded by the nearby star Rigel. The nebula's blue color is caused by dust grains scattering blue light more efficiently, a physical process similar to the one that makes Earth's daytime sky appear blue.