The Orion Nebula,a tremendous cloud of gas in which many hot,young stars are evolving rapidly toward cataclysmic cosmic explosions called supernovea.Energy released by nuclear explosions in such supernovea brought about the fusion of simple atomic nuclei,forming the more complex elements of which the earth,its atmosphere, and all living things are composed.The Orion Nebula, a tremendous cloud of gas in which many hot, young stars are evolving rapidly toward cataclysmic cosmic explosions called supernovea. Energy released by nuclear explosions in such supernovea brought about the fusion of simple atomic nuclei, forming the more complex elements of which the earth, its atmosphere, and all living things are composed