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NASA, Compton Gamma Ray Observatory, BATSE Team
Gamma Ray Bursts - The Most Powerful Objects in the Universe?
In the 1960's, the United States launched a series of satellites to look for very high energy photons, called Gamma Rays, that are produced whenever a nuclear bomb explodes. These satellites soon detected many bursts of Gamma Rays, but they were not coming from explosions on Earth. They were coming from outer space.Modern satellites, like the Compton Gamma Ray Observatory and NASA's Swift mission, have now detected thousands of these Gamma Ray Bursts. They happen about once a day and come from all over the sky, as the map shows. There seem to be two main types of bursts. Some are short, lasting less than 2 seconds. Others are longer, bursting for as long as 1000 seconds. We now believe that all Gamma Ray Bursts come from high-energy explosions that create black holes in distant galaxies. The two types of bursts come from two different ways to make a black hole.
Short Gamma Ray Bursts seem to come from binary systems, where two neutron stars are orbiting each other. These collapsed stars slowly lose energy and eventually merge together to form a black hole. The gamma rays come from leftover debris falling into the black hole.
Long Gamma Ray Bursts come from the deaths of stars that are between
50 and 100 times the mass of the Sun. At the end of their lives, these
massive stars collapse and explode as a type of
supernova that is unusually bright, called
a hypernova. The gamma rays shoot out along jets from these explosions,
which sometimes point toward the Earth.
