An analysis of archival X-ray data from NASA’s Rossi X-Ray Timing Explorer has revealed a clear separation between the characteristics of stellar-mass black holes and neutron stars, which is a consequence of the lack of the hard surface in the black holes. An artist’s impression of a stellar-mass black hole surrounded by a disk of gas and plasma gravitationally pulled from a close binary star companion. Image credit: NASA / CXC / M. Weiss. A black...
