October 6, 2020

expert reaction to Nobel prize for physics

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.

Dr Marco Bruni, Reader in Cosmology and Gravitation at the University of Portsmouth, said:

“In its best tradition, the Nobel Prize physics committee has assigned this year’s prize on results that have now been well established for a while, on the existence of black holes. It is remarkable that half the prize is going to Roger Penrose for his theoretical work in the 60s on the inevitability of black hole formation, with the other half going to Reinhard Genzel and Andrea Ghez for their astronomical observations in the 90s providing evidence for the existence of a super-massive black hole in the centre of our galaxy, the Milky Way. Physics advances through the interplay between theory and experiments, and this year’s prize, really recognise the importance of this interchange. It is also great to see a woman becoming a Nobel Laureate in physics – she is only the fourth since 1901 – so it is good to see the physics committee breaking away from a mostly men-only tradition.

“It is particularly great to see Roger Penrose awarded the Nobel prize in physics for his theoretical work on the inevitability of black holes formation. Penrose is no-doubt a genius, and he was inspired to work on physics problems by Dennis Sciama. Several of us at the University of Portsmouth’s Institute of Cosmology and Gravitation have a direct connection with Sciama, as we did our PhDs with some of the many of Sciama’s students. Sciama established a school in astrophysics in the 60s in Cambridge, when Penrose met him, and later in Oxford in the 70s and in Trieste (Italy) in the 80s. Many in Sciama’s school have worked on black hole’s physics and in cosmology, and in a sense the prize to Penrose is a recognition of this great legacy.”

Dr Laura Nuttall, Senior Lecturer in Gravitational Waves at the University of Portsmouth, said:

“It’s great to see Penrose, Ghez and Genzel recognised with the Nobel prize. Penrose is synonymous with black holes. His work in proving how black holes form, as well as their centre being a singularity, has opened so many fields, including that of searching for gravitational waves. Ghez and Genzel’s work has also inspired many, such as the Event Horizon Telescope who only released an image of a supermassive black hole last year. It’s wonderful, that their work is very much taken as a given today – of course black holes form from the collapse of matter and of course there’s a black hole at the centre of the galaxy. It’s easy to forget that this has not always been the case!”

Professor David Wands, Professor of Cosmology at the University of Portsmouth, said:

“Roger Penrose is a brilliant and original thinker: he brought a unique geometrical insight and applied it to physical theories to derive remarkable and profund results. His work established the inevitability of singularities in Einstein’s General Theory of Relativity, including his famous work with Stephen Hawking on the nature of the Big Bang singularity. It is great to see the Nobel committee recognise his exceptional contributions in mathematical physics.”

Prof Jerome Gauntlett, Imperial College London, Professor of Theoretical Physics:

“I’m absolutely delighted with today’s announcement of the Nobel Prize for Physics!

“Black holes are structures in the very fabric of space and time and are amongst the most extraordinary structures that are known to exist in the universe. Within General Relativity, Einstein’s theory of gravity, they have the remarkable property that once one passes through the event horizon there is no way back. It is necessarily a one way journey to something called a spacetime singularity, where the current laws of physics break down. Black hole solutions to Einstein’s equations were first found shortly after Einstein formulated his theory in 1915, but it was decades before their properties were properly understood and it started to become accepted that they might actually exist in nature.

“Roger Penrose laid the foundations for our modern understanding of black holes in the 1960s. In a highly original and profound development he introduced new mathematical methods to study Einstein’s equations. His work revealed that in certain situations the formation of a black hole in the gravitational collapse of a star is essentially inevitable and this is when black holes started to be taken more seriously. Furthermore, his work showed that inside every black hole there must be a spacetime singularity. This is in fact a wonderful opportunity for fundamental physics: if one wants to understand the laws of physics that takes us beyond Einstein’s theory and the laws of quantum mechanics, we should think about black holes!

“We now know through the work of Ghez and Genzel that there is a supermassive black hole in the centre of our galaxy. Over the past few years we have also seen spectacular confirmation of the existence of black holes via the gravitational waves that they emit when they merge with each other. We are certainly living in a very exciting era for black hole science.”

Oliver Jennrich, ESA scientist working on LISA, said:

“Black holes play a fundamental role both in our understanding of the Universe and the formation of the structures that we see today, such as galaxies and groups of galaxies. The discovery of a black hole in the center of our galaxy through the observation of the orbit of stars not only confirms our understanding of General Relativity, it also raises many more new questions e.g. on the history of such massive objects and their influence on their environments. The planned ESA mission LISA, a mission to observe gravitational waves will be able to detect mergers of such massive black holes essentially everywhere in the Universe and will be able to shed light on the questions on how the massive black in the centers of galaxies form and about their role in the formation of the large-scale structures in the Universe.”

Dr. Matteo Guainazzi, ESA scientist working on Athena, said:

“The Nobel Prize to Prof. Genzel and Ghez constitutes the culmination of a decade-long endeavor to find unquestionable observational evidence of the existence of astrophysical black holes. This stream of investigation was triggered by the theoretical insight that black holes are an inevitable consequence of Einstein’s General Relativity as prof. Penrose’s investigation brilliantly showed”.

Erik Kuulkers, ESA scientist working on INTEGRAL, said:

“The work by Penrose, Genzel & Ghez has been seminal, which culminated, into the first image of a black hole captured last year. We are now able to not only understand, but also see the most extreme physics in the universe at play.”

Dr Venki Ramakrishnan, President of the Royal Society, said:

“It is a pleasure to see this year’s Nobel Prize in Physics recognise three outstanding scientists, and their teams, for ground-breaking work on black holes which simultaneously transformed our understanding of the universe and captured the imaginations of millions.

“Professor Penrose’s seminal paper demonstrated mathematically that not only could black holes exist, but that their formation is a consistent and predictable outcome of a universe governed by general relativity. This work showed black holes were there to be found – but it was the painstaking, long-term study of the centre of our own Milky Way, by groups led by Professor Ghez and Professor Genzel, that gave the best evidence yet of a black hole on our doorstep.

“Through decades of patient application, they have refined the technology and techniques for studying our galaxy, and in doing so, opened up new possibilities and questions to explore.”

Professor Grahame Blair, Director of Programmes at STFC, said: 

“The groundbreaking work carried out by Professor Sir Roger Penrose all those decades ago truly laid the foundation for black hole science. The development of theoretical ideas of space and time has paved the way for exciting experimental discoveries in astronomy and the study of gravitational waves, as well as the remarkable observations made by fellow winners Professors Reinhard Gerzel and Andrea Ghez.

“Enhancing our knowledge of the fundamental forces of particles and nature is the motivation that underpins STFC theoretical and experimental programmes. 

“Understanding these mysterious celestial phenomena is vital if we are to understand how the universe was formed, and ultimately how it will come to an end.”

Dr Stephen Wilkins, Head of Astronomy at the University of Sussex, said:

“The 2020 Nobel prize for Physics celebrates three pioneering scientists who have spent their careers trying to understand black holes. 

“Black holes are not only a key prediction of Einstein’s 100 year old General Theory of Relativity but are now believed to play a critical role in the regulating the growth of galaxies like the Milky Way.“

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

“The Genzel/Ghez work is impressive in combining near-infrared observations with very high angular resolution. This work by both groups has continued, with improving sensitivity, for long enough to monitor complete orbits of the closest-in stars: straightforward application of Newton’s law then gives the firmest evidence for the actual mass of the dark object in the Galactic Centre. (The existence of a black hole in the galactic centre was predicted nearly 50 years ago and has gradually strengthened.)

“Genzel has a superb lifetime record. He and Eisenhauer have more recently achieved a major ‘leap forward’ in developing and using an instrument, called GRAVITY, which links the four telescopes of the VLT array into an interferometer.

“The sustained programmes led by Genzel and Ghez have, in combination with data in other wavebands, clarified our understanding of the complex physics and ‘weather’ in the Galactic Centre.  However, even the innermost stellar orbits in the Galactic Centre don’t extend any closer than a hundred times the radius of the hole. They provide (via essentially Newtonian arguments) excellent determinations of the central mass, and also a limit on deviations from general relativity in the weak -field domain. But it is other data – especially radio interferometry, data from X-ray astronomy, and above all LIGO – which currently offer direct evidence that black holes have the properties that relativity theory predicts.”

Philip Diamond, Executive Director of the Royal Astronomical Society, said:

“Half a century ago, even the very existence of black holes was still controversial. Through the pioneering work of Penrose, Genzel and Ghez, we not only have a vastly better understanding of how they are formed, but are able to say convincingly that giant black holes are found at the centre of every galaxy, including our own. My congratulations to all three winners!”

Professor Arttu Rajantie, Professor of Theoretical Physics at Imperial College London, said:

“This is a very well-deserved Nobel Prize. Through gravitational wave observations, black holes are going to dramatically advance our understanding of fundamental physics over the coming decades. Today’s Nobel laureates laid the foundations for that, both theoretically and observationally, by understanding the meaning of the black hole solutions of general relativity and by demonstrating that they really exist in the Universe.”

Professor Tom Marsh of the Astronomy and Astrophysics Group at University of Warwick said:

“Roger Penrose established the theoretical basis for believing that black holes were more than just theoretical constructs: they could actually form from stars. Reinhard Genzel’s and Andrea Ghez’s work is an astronomical tour de force and direct proof of the existence of the closest super-massive black-hole to Earth. They form a brilliant theoretical and experimental confirmation of a key consequence of Einstein’s General Theory of Relativity.”

Dr David Clements, Astrophysicist, Imperial College London, said:

“The long term monitoring of the centre of our own galaxy that has led to the discovery of the supermassive black hole at its centre, and half of this year’s Nobel Prize, was an amazing achievement. It built up data over decades from many different telescopes, with continually improving instrumentation and techniques. It was a marathon run, and has produced fantastic results.”

Professor Boris Gaensicke, Professor in the Astronomy and Astrophysics Group at the University of Warwick, said:

“It is fantastic to see the observational studies carried out by Andrea Ghez and Reinhard Genzel, beautifully simple in concept yet so powerful in constraining the properties of the black hole at the centre of the Milky Way, being awarded this year’s Nobel Prize in Physics. “

Roger Highfield, Science Director at the Science Museum, said:

“This Nobel prize acknowledges Sir Roger’s work on black holes but he has been hugely influential in so many other ways, from his bestselling books, notably on the limitations of computers and quantum theory, our most successful theory, to his discovery of aperiodic tiling named in his honour (made famous by a battle with a manufacturer of quilted toilet paper, who appropriated his idea) and his artistic inclinations, notably his work with his father, Lionel, that inspired Escher and that can be seen in his hand-drawn slides and transparencies.”

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.”

https://www.nobelprize.org/prizes/physics/2020/press-release/