Hypernovae 

     Hypernova, it describes when a really big star that collapses at the end of its lifespan. Until the 1990s, it referred specifically to an explosion with an energy of over 100 supernovae (10⁴⁶ joules); such explosions were proposed to explain the origin of exceptionally bright gamma ray bursts. An extensive sky search found several apparent hypernova remnants

, but too few to support the hypothesis.

     The term came to be used to describe the supernovae of the biggest stars, the hypergiants, which have masses from 100 to 150 times that of the Sun. Decaying a short-lived isotope of 

nickel, which is believed to provide much of a hypernova's light.

     The radiation output of a nearby hypernova could cause serious damage to our solar system, but no hypergiants have been located near Earth. It is conjectured that a hypernova may have caused a mass extinction on Earth 440 million years ago.