Nobel Prize winner Penrose says biggest black hole riddle is the singularity

FILE PHOTO: Professor Sir Roger Penrose poses for a group photograph with other members of the Order of Merit and Britain's Queen Elizabeth ahead of a luncheon at Windsor Castle, Berkshire, Britain May 7, 2019. Jonathan Brady/Pool via REUTERS/File Photo

LONDON (Reuters) - Roger Penrose, who won the 2020 Nobel Prize for Physics, said on Tuesday that the biggest outstanding riddle about black holes was the question of what went on in the very centre of them - the singularity, where density and gravity become infinite.

Penrose, professor at the University of Oxford, won half the prize of 10 million Swedish crowns ($1.1 million) for his work using mathematics to prove that black holes are a direct consequence of Albert Einstein's general theory of relativity.