The Bullet Cluster, 3.8 bln light years from Earth, where NASA's Chandra X-ray Observatory is searching for the presence of antimatter.
(X-ray: NASA/CXC/CfA/M.Markevitch et al.; Optical: NASA/STScI; Magellan/U.Arizona/D.Clowe et al.)
Email addresses are required but never displayed.
The show is a co-production of WNYC Radio and Public Radio International, in collaboration with The New York Times and WGBH Boston.
Major funding provided by: