Stellar-Mass Black Holes: Born from Collapsing Stars

Stellar-mass black holes form when massive stars collapse at the end of their lives.
They typically range from about 3 to 100 times the mass of the Sun.
The collapse occurs after a supernova explosion, leaving behind the black hole.
Despite their mass, they’re only a few kilometers across—smaller than a city.
Stellar black holes are the most common type in the universe.
They can “feed” on companion stars, creating bright X-ray binaries.
Gravitational waves detected by LIGO often come from merging stellar black holes.
Some are “quiet,” giving away their presence only through gravitational effects on nearby stars.
The first confirmed stellar-mass black hole was Cygnus X-1, discovered in the 1960s.
Studying them helps scientists understand stellar evolution and the extremes of gravity.