How would a supernova explosion near our solar system affect Earth?
David DeRoo, Silver Spring, Maryland
A supernova explosion might affect Earth in several ways. A blast of ultraviolet light from the explosion's shock wave would hit the exploding star's surface. The expanding gas releases deadly gamma rays from radioactive decay. Cosmic rays accelerated in the remnant can destroy Earth's fragile ozone layer and allow the Sun's ultraviolet rays to fry the surface.