Drawing of a massive star collapsing to form a black hole. Energy released as jets along the axis of rotation forms a gamma ray burst that lasts from a few milliseconds to minutes. Such an event within several thousand light years of Earth could disrupt the biosphere by wiping out half of the ozone layer, creating nitrogen dioxide and potentially cause a mass extinction.
Nicolle Rager Fuller of the NSF
Attribution
National Science Foundation <a rel="nofollow" class="external text" href="http://www.nsf.gov/news/news_images.jsp?cntn_id=104440&amp;org=NSF">Press Release 05-156: Gamma-Ray Burst Smashes a Record</a>