Cygnus X-1
The first confirmed black hole
Discovered as an intense X-ray source in 1964, Cygnus X-1 is a stellar-mass black hole greedily devouring its blue supergiant companion. Its 1974 confirmation settled a famous bet between Stephen Hawking and Kip Thorne.
Image: Optical / DSS
Vital statistics
Type
Stellar-mass Black Hole
Mass
~21 Suns
Distance
~7,200 light-years
Companion
HDE 226868 (blue supergiant)
Did you know
Hawking conceded his bet against its existence in 1990.
Fact 01
Pulls a stream of gas from its supergiant companion.
Fact 02
Spins at >95% the speed of light.
Fact 03
Research & publications
Jump straight into peer-reviewed papers, preprints and authoritative references for Cygnus X-1.
arXiv (preprints)
Open-access preprints in physics & astrophysics.
NASA ADS
The definitive bibliographic database for astronomy.
Google Scholar
Cross-publisher academic search.
Nature
Peer-reviewed articles in Nature & sister journals.
Wikipedia
Encyclopedic overview & onward references.
Tip: ask the Research AI for a curated reading list → /research
