Asteroides

El riesgo concreto y cierto de un asteroide o grupo de asteroides impactando en la Tierra en un futuro no muy lejano. Preocupante (visto en Instapundit):

Astronomer David Tholen spotted it last year in the early evening of June 19, using the University of Arizona's Bok telescope. It was a new "near-Earth object," a fugitive asteroid wandering through space to pass close to Earth.

Tholen's team took three pictures that night and three the next night, but storm clouds and the moon blocked further observations. They reported their fixes to the Minor Planet Center in Cambridge, Mass., and moved on.

Six months later, Tholen's object was spotted again in Australia as asteroid "2004 MN4." In the space of five days straddling Christmas, startled astronomers refined their calculations as the probability of the 1,000-foot-wide stone missile hitting Earth rose from one chance in 170 to one in 38.

They had never measured anything as potentially dangerous to Earth. Impact would come on Friday the 13th in April 2029.