Astronomers have discovered the lightest known pair of neutron stars — two ultradense stellar remnants that circle each other every 2 hours, 22 minutes, veering toward an inevitable collision about 82 million years from now. By timing radio pulses from one of the stars, the researchers detected three subtle effects predicted by Albert Einstein's general theory of relativity and found that the theory describes the pair's motion to within about 1% — proving the visionary physicist right yet again. The researchers published their findings Sept. 15 in the journal Physical Review Letters.Neutron stars are the collapsed cores of massive stars that exploded as supernovas. Each packs more mass than ...