Next generation

Venturing forth to illuminate cosmic rays—tiny particles entering Earth’s atmosphere from outer space at nearly light speed—a team led by physics professor Dietrich Müller launched an unmanned helium balloon over Antarctica December 12. The balloon, made of enough plastic to blanket the Sears Tower and cruising at approximately 130,000 feet, carried TRACER, a three-ton instrument that “successfully collected cosmic-ray data for ten days,” Müller says. Returned to ground by parachute and recovered in good condition, TRACER could help researchers determine where cosmic rays originate by identifying their chemical composition. Data analysis is in progress, and first results are expected later this year.—M.L.