Explosions In Space May Have Initiated Ancient Extinction On Earth Scientists at NASA and the University of Kansas say that a mass extinction on Earth hundreds of millions of years ago could have been triggered by a star explosion called a gamma-ray burst. The scientists do not have direct evidence that such a burst activated the ancient extinction. The strength of their work is their atmospheric modeling -- essentially a "what if" scenario. The scientists calculated that gamma-ray radiation from a relatively nearby star explosion, hitting the Earth for only ten seconds, could deplete up to half of the atmosphere's...