Roger Penrose won the 2020 Nobel Prize in Physics for showing that black-hole formation is a robust prediction of general relativity.
Penrose’s breakthrough came in the 1960s, when he developed powerful mathematical methods for studying gravitational collapse. His work showed that a sufficiently massive collapsing star can form a singularity under realistic conditions, rather than requiring a perfectly symmetrical model. This established that black holes were not merely mathematical curiosities in Einstein’s equations.
The Nobel award was shared: Penrose received one-half, while Reinhard Genzel and Andrea Ghez jointly received the other half for discovering the supermassive compact object at the center of the Milky Way, now identified as Sagittarius A*. The prize therefore recognized both theory and observation.
A common mix-up is to credit Stephen Hawking for this specific Nobel-winning result. Hawking made major contributions to black-hole thermodynamics and singularity theory, but he was not an awardee of the 2020 Physics Nobel.