Stellar-mass black holes are the result of a gravitational collapse of a massive star at the end of its life. The core of such star collapses to singularity – a point of infinite density and space-time curvature – that is cloaked in the event horizon. The gravitational force of the resulting black hole is so strong that no light or signal can escape its event horizon. This essay will address how astronomers search for stellar-mass black holes, will attempt to describe their characteristics, and will also discuss the current knowledge on Milky Way black hole candidates and their companion stars, and the connection between X-ray sources and black holes.
