A supernova is a STAR that explodes. It suddenly increases in brightness by a factor of many billions, and within a few weeks it slowly fades. In terms of the human lifespan, such explosions are rare occurrences. In our Milky Way galaxy, for example, a supernova may be observed every few hundred years. Three such explosions are recorded in history: in 1054, in 1572, and in 1604. The CRAB NEBULA consists of material ejected by the supernova of 1054. …showed first 75 words of 694 total…

…showed last 75 words of 694 total…explosions could have mixed with the solar nebula, eventually becoming part of the structures of the Sun, the Earth, and all living things. Bibliography Bibliography: Clark, D. W., and Stephenson, F. R., eds., Historical Supernovae (1977); Jastrow, Robert, and Thompson, Malcolm, Astronomy (1984); Marschall, Laurence A., The Supernova Story (1988); Murdin, Paul and Leslie, Supernovae (1985); Shy, Frank, The Physical Universe (1982); Woosley, Stan, and Weaver, Tom, "The Great Supernova of 1987," Scientific American, August 1989; Zeilik, Michael, and Gaustad, John, Astronomy (1983).