DO COSMIC rays deplete the Earth’s protective ozone layer? The controversial theory that these high-energy particles drive the chemical reactions eating away at stratospheric ozone has just been given a boost.
Several years ago, a team led by Qing-Bin Lu of the University of Sherbrooke in Quebec, Canada, reported laboratory experiments suggesting that electrons liberated by cosmic-ray collisions could break down chlorofluorocarbon molecules, releasing chlorine atoms that tear ozone molecules apart. Chlorine production is usually thought to be triggered by UV light.
If Lu’s suggestion is correct, ozone levels should fall then rise every 11 years, in step with changes in cosmic-ray intensity driven by the…
