The Galaxy's 62-Million Year Extinction Oscillator

Hugh Pickens writes: "Cosmologist Adrian Mellott has an interesting article in Seed Magazine where he discusses his search for the mechanism behind the mass extinctions in earth's history that seem to occur with a period of about 62 million years. Scientists have identified nearly 20 mass extinctions throughout the fossil record including the end-Permian event about 250 million years ago that killed off about 95 percent of life on Earth and the mass extinction at end of the Cretaceous period 65 million years ago when dinosaurs' domination of the earth reached its end. Mellott notes that as our solar system slowly orbits the Milky Way's center, it oscillates through the galactic plane with a period of around 65 million years. "The space between galaxies is not empty. It's actually full of rarefied hot gas," says Mellott. "As our galaxy falls into the Local Supercluster, it should disturb this gas and create a shock wave, like the bow shock of a jet plane" generating cascades of high-energy subatomic particles and radiation called "cosmic rays" causing enhanced cloud formation and depletion of the ozone layer killing off many small organisms at the base of the food chain and potentially leading to a population crash. So where is the earth now in the 62-million year extinction cycle? "If the past is any guide, we are on the downside of biodiversity, a few million years from hitting bottom," writes Mellott. "We now must try to understand the 62-million year cycle itself by seeking correlations with things like the rate of seabed fossil formation or the rates of species origination and extinction. Only by gathering these clues can we fathom the diversity recession that seems to lie in our geological future.""