Gamma ray burst |
|
Gamma ray bursts were discovered in the 1970's. They are ten to twenty second flashes of intense gamma rays that arrive from any direction, at random, once or twice a day. For a few seconds a gamma ray burst outshines the Sun in terms of total photon energy. Gamma ray bursts were a major puzzle for many years until it was realized that they are created as a black hole is formed from the collapsing core of a dying star. Most bursts that we observe come from very distant galaxies. Each burst represents a prodigious release of energy from a sudden, catastrophic, gravitational collapse. Some bursts have a complex structure as, it is believed, left-over bits of the star are 'swallowed' by the newly created hole up to half an hour after the main event. |
| It is fortunate that our vision is necessarily insensitive in the gamma ray region of the electromagnetic spectrum, otherwise we would be woken at night by occasional blinding ten-twenty second flashes of daylight. |