This picture shows the Rosette Nebula, a star forming region in the constellation Monoceros. The bright whitish-blue stars near the center of the nebula have formed only recently, and are now in the process of blowing away the remaining gas out of which they formed. The gas, glowing red in this picture, is heated and excited by the stars. The different star colors indicate stars of differing temperatures, with orage-yellow stars having surface temperatures of only a few thousand degrees and the bluest stars having temperatures over 20,000 degrees. Separate pictures taken with different color filters have been combined into the single color representation you see here.