Astronomy Picture of the Day

Explanation: The nebula surrounding bright star S Mon is filled with dark dust and glowing gas. The strange shapes that haunt this star forming region originate from fine interstellar dust reacting in complex ways to the energetic light and hot gas being expelled by the young stars. The above picture, in representative color, isolates the northern part of a greater nebula designated NGC 2264, which lies about 2500 light-years away and includes the Cone Nebula. The blue glow directly surrounding S Mon results from reflection, where neighboring dust reflects light from the bright star. The more diffuse red glow results from emission, where starlight ionizes hydrogen gas. Pink areas are lit by a combination of the two processes. A small group of stars surrounds S Mon, the brightest star in the picture and a star visible with the naked eye toward the constellation of Monocerus.