Profile of Edward H. Egelman

Cover image: Pictured is a hydrodynamic simulation of a supernova blast wave colliding with and compressing the solar wind. Earth's orbit (blue dashed circle) and the Sun (red dot) are shown for scale. Brian D. Fields et al. suggest that a significant decrease in stratospheric ozone caused by a supernova explosion may have occurred during the final extinction event in the Late Devonian. The supernova may have increased megafauna extinction levels by accelerating cosmic rays capable of delivering ionizing radiation to Earth for approximately 100,000 years. The findings suggest that the collapse and explosion of a massive star could induce such an extinction. See the article by Fields et al. on pages 21008–21010. Image credit: Jesse A. Miller and Brian D. Fields.