Some of the most puzzling worlds in our telescopes’ catalogs may not be worlds at all, but relics from the first instants after the Big Bang. Instead of rocky or gaseous spheres, a handful of “planets ...

Astronomers have spotted a monster black hole in the early universe that's gorging on matter at more than twice the theoretical limit. The discovery deepens the mystery of how some black holes born ...

On Sept. 14, 2015, physicists attained the long-sought goal of detecting gravitational waves, the shockwaves spewed out by such cataclysmic events as the violent merger of two black holes. Now, in the ...