Most people agree that supernovae are the universe's most powerful explosions. Recently, another event has been granted similar distinction: hyper novae, which are the fading afterglows of gamma ray bursts. Gamma ray bursts were found more than thirty years ago, but their nature is still unknown. Only recently have astronomers been able to obtain accurate distance estimations, firmly placing gamma ray bursts within the field of cosmology. Given the very long distances suggested by red shift data, gamma ray bursts are the strongest known examples of catastrophic energy releases. Every day, a unique high energy fireworks display is observed by gamma ray detectors aboard satellites near Earth and in interplanetary space; however, the cause of these explosions remains a mystery. Although there is still much to learn about Gamma ray bursts recent x ray optical, and radio observations have produced significant advances in our knowledge of them.
supernova is the intense and bright explosion of a star (plural: supernovae or supernovas). A supernova is produced when a white dwarf is set off on a path toward runaway nuclear fusion or in the latter stages of the life of a big star. The initial object, known as the progenitor, either totally collapses to form a diffuse nebula or collapses to a neutron star or black hole. A supernova's optical luminosity can reach a peak similar to that of an entire galaxy and then gradually decrease over a few weeks or months.
Kepler 's supernova in 1604, which emerged shortly after Tycho's supernova in 1572 and was visible to the unaided eye, was the last supernova to be directly viewed in the Milky Way. Discoveries of the remains of more recent supernovae indicate that, on average, the Milky Way experiences three supernovae per century. Observations of supernovae in other galaxies further support this theory. Modern astronomical instruments would most likely be able to observe a supernova in the Milky Way. The most recent supernova visible to the unaided eye was S N1987 A, the explosion of a blue super giant star in the Milky Way's satellite galaxy, the Large Magellanic Cloud.
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