Caption: Cometary globules are isolated, relatively small clouds of gas and dust within the Milky Way. The head of the nebula is itself opaque, but glows because it is illuminated by light from very hot stars nearby. Their energy is gradually destroying the dusty head of the globule, sweeping away tiny particles that scatter the starlight as a faint, bluish reflection nebula. This particular globule also shows a faint red glow, probably from excited hydrogen, and seems about to devour an edge-on spiral galaxy, which in reality is millions of light years away, far beyond CG 4.
Copyright: (c) 1992 Anglo-Australian Telescope Board, photograph by David Malin
