Galactic cycles might cause mass extinctions

University of Kansas Professor of physics and astronomy Adrian Melott has written a fascinating and accessible piece in Seed magazine noting a correlation between the oscillation of our solar system and an apparent 62-million year cycle of mass extinctions visible in the fossil record. Evidence seems to indicate that, as the solar system 'bobs' up into the Galactic north of the Milky Way's disk plane, it's bombarded with extra cosmic rays originating from the local supercluster. Cosmic rays can contribute to mutation (usually deadly - superheroes notwithstanding), as well as degrading of the ozone layer - both nasty effects which could, just conceivably, trigger mass extinctions on a (cosmologically) regular basis.