Some black holes seem impossible Alexandr Yurtchenko/Alamy
Of all the prevailing ideas for how black holes emerge, none could account for the existence of an impossibly large type of black hole detected in 2019 – but now we may know how it could have formed.
In May 2019, researchers at the Laser Interferometer Gravitational-Wave Observatory (LIGO) in the US and its Italian counterpart Virgo measured ripples in space-time called gravitational waves and determined that their signal was the result of two black holes merging.
Stellar-mass black holes like these arise when a star becomes too large to support its own weight…
