The latest, and one of the most intriguing, forays into the debate comes from three scientists at the Israel Institute of Technology. Astrophysicists Arnon Dar, Ari Laor and Nir Shaviv speculate that radiation from the collision of distant stars caused some mass extinctions. Mutants on Earth At the same time, they argue in a report published in the June 29 issue of Physical Review Letters, the radiation would cause mutations, leading to the emergence of entirely new species on Earth. Such a violent collision blasts out jets of high-energy particles called cosmic rays. If Earth passed through one of these jets within about 3,000 years of the collision, the scientists theorize, the cosmic rays would be intense enough to destroy the ozone layer that protects Earth from harmful solar radiation, and make much of the planet highly radioactive.
Radioactive particles can destroy an organism's central nervous system and cause death within days.
Scientists have documented at least five major extinctions, in which many forms of life were eliminated, over the past 570 million years, as well as many lesser events in which only a few species died out. Cosmic rays could do that, the scientists argue, and much evidence should be awaiting discovery in the rocks and fossils of ancient Earth. A high-energy particle smashing through a rock leaves a track. Sensitive instruments should be able to find those tracks. The scientists are calling on their colleagues around the world to search for evidence of high energy particles in fossils and rocks that correspond in age to known periods of mass extinctions.