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Source: United Kingdom – Science Media Centre

The 2020 Nobel Prize in Physics, has been half awarded to Prof Roger Penrose for his discovery that black hole formation is a prediction of the general theory of relativity, and the other half of the award was jointly received by Prof Reinhard Genzel and Prof Andrea Ghez for the discovery of a black hole at the centre of our galaxy.

Prof Martin Rees, Astronomer Royal and Fellow of Trinity College, University of Cambridge, said:

“Penrose is amazingly original and inventive, and has contributed creative insights for more than 60 years.  There would, I think, be a consensus that Penrose and Hawking are the two individuals who have done more than anyone else since Einstein to deepen our knowledge of gravity.  (Other key figures would include Israel, Carter, Kerr, and numerous others.)  Sadly, this award was too much delayed to allow Hawking to share the credit with Penrose.

“It was Penrose, more than anyone else, who triggered the renaissance in relativity in the 1960s through his introduction of new mathematical techniques. He introduced the concept of a ‘trapped surface’.  On the basis of this concept, he and Hawking (more than a decade younger) together showed that the development of a singularity – where the density ‘goes infinite’ – was inevitable once a threshold of compactness had been crossed (even in a generic situation with no special symmetry).  This crucial discovery firmed up the evidence for a big bang, and led to a quantitative description of black holes.”

Prof Toby Wiseman, Professor of Theoretical Physics at Imperial College London, said:

“This is a remarkable Nobel prize that spans from understanding the mathematics of black holes through to their experimental verification.

“A key step in the story of black holes was Roger Penrose’s singularity theorem. This beautiful mathematics proves that black holes form any time when too much matter is in a small volume of space.  It revolutionised our thinking about these bizarre mathematical solutions to Einstein’s equation of gravitation, General Relativity. For decades before, the black hole solution was thought to be a mathematical curiosity, not physical reality. Penrose showed that if you believe Einstein, then black holes form under very general conditions, such as when certain stars die.  They must be a physical reality.

“The prize also celebrates the remarkable observations of the supermassive black hole, Sagittarius A*, at the centre of the Milky Way, our own galaxy. For decades astronomers have been observing the stars near the very centre of our galaxy and have reconstructed their orbits about an invisible but very small and massive object.  While we can’t see this directly it precisely fits with the black hole theory, and from looking at these orbiting stars we can deduce it has a huge mass, roughly that of 4 million suns, all put into a tiny object predicted to be just ten million kilometres in radius.”

Prof Sadegh Khochfar, Professor of Theoretical Astrophysics at The University of Edinburgh, said:

“This year’s prize recognises all that is good about astrophysical research. Making theoretical predictions on the fundamentals of physics and embarking on a challenging decade-long observational campaign to test them. The existence of black holes provides deep understanding of the laws of gravity and opens up the question on their formation and evolution within the context of an evolving Universe.

“With the existence of a super-massive black hole proven in the centre of our own galaxy we can now embark on testing the laws of gravity even with higher precision in extreme conditions such as around a black hole.”

Professor Martin Ward, Emeritus Temple Chevallier Professor of Astronomy at Durham University, said,

“This a great example of theoretical insight and prediction followed by state-of-the-art observational evidence.  Using classical Newtonian mechanics the nearest super massive black hole at our Galactic Centre was revealed, and so ‘Darkness made visible’.”

Prof Tom McLeish, Professor of Natural Philosophy at the University of York, said:

“Penrose, Genzel and Ghez together showed us that Black Holes are awe-inspiring, mathematically sublime, and actually exist ”

Prof Jim Al-Khalili, Professor of Physics, Professor of Public Engagement in Science, EPSRC Media Fellow, University of Surrey, said:

“I can’t tell you how delighted I am that Roger Penrose has been recognised with a Nobel Prize. For many outside of physics he has been see as being in the shadow of his long-time collaborator, the late Stephen Hawking. But while Einstein’s general theory of relativity predicts the existence of black holes, Einstein didn’t himself believe they really existed. Penrose was the first to prove mathematically, in 1965, that they are a natural consequence of relativity theory and not just science fiction.”

MIL OSI United Kingdom