The 2020 Nobel Prize in Physics has been awarded to Roger Penrose for his discovery that “the formation of black holes is a strong prediction of the general theory of relativity”. He shares with Reinhard Ganzel and Andrea Gaze in search of a supermassive compact object object at the center of our galaxy.
Penrose, Oxford University’s Emirates Rouge Ball Professor of Mathematics, will receive a prize money of 10 million Swedish kronor (over US 1. 1.1 million). He helped strengthen the theoretical foundations for black hole physics in the 1960s, a direct result of general relativity.
Genzel is the executive director of the Max Planck Institute for Extraterrestrial Physics in Germany and a professor at the University of California, Berkeley, while Ghess is a professor at the University of California, Los Angeles. They will each receive a quarter of the prize money. Ganzel and Gaz are each the leading astronomical groups that have mapped the orbits of the stars near the center of our galaxy – a region known as Sagittarius A – which gives us the best evidence of today’s history that there is a supermassive black hole at the center of our galaxy. That work was greatly aided by the development of advanced adaptive tools to prevent the distorting effects of the Earth’s atmosphere.
“The search for this year’s winners has broken new ground in the study of compact and supermassive objects,” David Haviland, chairman of the Nobel Committee on Physics, said in an official statement. “But these foreign objects still raise many questions that request answers and encourage future research. Not only questions about their internal structure, but also about how to test our theory of gravity in extreme conditions in the vicinity of the black hole. There are also questions. “
Darker stars
The black holes are a precursor to the “Dark Stars” conceived in 1793 by John Mitchell and Pierre-Simon L. P. Place in 1796. In a 1783 paper on the Philosophical Transactions of the Royal Society, Michelle argued that according to classical (Newtonian) mechanics, a star about the same density as our Sun, but a 500 ratio radius, would pull gravity so strongly that light would trap itself. Laplace made similar calculations in his own 1799 paper.
Our modern concept of blackholes dates back to 1916, when Albert Einstein’s general theory of relativity was quite new and revolutionized our understanding of gravity. Einstein envisioned space-time that is curved, not flat, and so gravity is not so much a force as it is a space-time that is bent out of shape by the presence of mass or of radiance. How much mass or energy is determined determines the degree of curvature, and the more curvature there is, the stronger the gravitational pull. Since space and time are one, what happens to space also affects time: since space is steamy, time lengthens or contracts accordingly. Therefore, time is directly proportional to the force of the gravitational field, and the strength of that field depends on the distance.
Einstein’s equations opened up a whole new field of theoretical possibilities. It was only after a physicist named Carl Schwarzschild published his final paper by Einstein that his way of overcoming the horrors of war – during World War I – began to fight with various solutions during heavy shelling on the front. Schwarzschild eventually blocked a road where the equations “blew up”, and his work provided an initial description of a black hole. (The term was coined by Robert Dickey in 1960, and John Wheeler later helped popularize it.) An extremely massive mass could cut a piece of space to create a black hole, surrounded by a horizon of events, a hypothetical point of no return. Can escape (not even light). Its mass is large, its black hole is large, and its event horizon is large in diameter.
Initially, physicists considered these foreign objects to be purely theoretical, although Robert Opp Penheimer and his student Hartland Snyder broke some preliminary calculations to show that large stars could break out dramatically to form black holes many times larger than our Sun. “The stars thus shut themselves off from any communication with the distant observer; only its gravitational field is maintained,” they concluded. However, the general consensus was that this is not a real model of anything that really forms in our universe. Then physicists discovered quarks in the 1960s, which are known to be the brightest in the universe. Scientists have concluded that the source of all these radiations must be something falling into a huge black hole. So black holes can be “real” after all.
Roger Penrose decided to tackle the problem of showing how black holes actually formed, and later recalled the moment he reached his prime in the fall of 1964. While traveling from London to visit a colleague, he envisioned a “trapped surface”: a closed, two-dimensional surface that draws all light rays to the Infinite Ga ense Center – what we now call loneliness, where time and space end inside a black hole Is. Penrose showed – using their nickname Penrose diagrams like other tools – that once such a relative surface was formed, in general relativity, the inevitable fall towards loneliness could not prevent anything.
Journey to the center of the galaxy
Establishing a solid theoretical foundation for the existence of black holes was not the same as direct observation, however. Our Milky Way galaxy is a flat disk measuring about 100,000 light-years, and our Sun is just one of the few hundred billion stars inside it. Physicists have long thought that it could have a supermassive black hole at its center, which is supported by the discovery of radio waves emanating from a central region called Sagittarius A *. So it felt like the ideal candidate for further investigation.
But how, exactly, does an object “observe” an object from which no light can escape? It must be done indirectly, by projecting the gravitational effects such a object will focus on objects near it – such as the orbits of nearby stars. These earth-based telescopes must be accompanied by observations in close infrared, as any light in the optical spectrum will be obscured by interstitial gas and dust. The better it can track the speeds, the easier it will be to make the necessary calculations.
Since the early 1990s, Genzel’s team has relied on the telescopes of the European Southern Observatory in Chile, especially the very large telescope array. Ghez’s team, meanwhile, relied on the Cake Telescope in Hawaii.
The work was arduous, time-consuming, and hampered by the turbulent effects of the Earth’s atmosphere. Genzel and Gaz and their respective teams developed a technique called “spectacle imaging” to meet that challenge. It involves holding the data together to produce many highly sensitive, short-touch and sharp images of a given star. But this proved to be effective only for the brightest stars orbiting Sagittarius A *, and it also took years to obtain the necessary information about the velocities of all those stars.
The emergence of adaptive optics as a game-changer in the late 1990s. This uses the “guide star” as the first point of observation – either a real star or an artificially made point source, which can be achieved using a powerful laser to excite sodium atoms in the upper atmosphere. Once the position and brightness of the guide star have been determined, that information can be used to calculate the effects of atmospheric storms. This, in turn, enables astronomers to quickly use distorted letters to compensate for distortions.
The use of adaptive optics allows for longer exposure, so more stars can be observed at greater imaging depths. Both teams can monitor the motion of about 30 bright stars near Sagittarius A * on a very short time basis. Both were able to image and analyze a single star, especially near the galactic center S2, which completed orbit in less than 16 years (compared to the 200 million years it took our Sun to complete its orbit around the center of the galaxy) – and their data are complete. To match. Conclusion: The object in the center of the galaxy is a supermassive black hole.
NASA / Pubic Domain
We look forward to more exciting explorations of black holes in the future. For example, it is very likely that we will soon have a realistic image of a black hole in the center of our galaxy, courtesy of the Event Horizon Telescope, which made headlines last year for a stunning image of a black hole in the middle. Messier 87 galaxy, about 55 million light years from Earth. And ongoing LIGO / VIRGO collaboration continues to detect gravitational waves generated by black hole mergers, in other cosmic events.
Giovanni Losurdo, a spokeswoman for Virgo Collaboration, said in a statement in response to the award announcement that research on the once-foreign-obscure dark universe is becoming increasingly mainstream. “In fact, the discovery of the gravitational waves announced in 2001 was also the first direct discovery of a black hole. Since then, Virgo and Ligo have discovered dozens of black hole binary systems that allow us to see physics more closely. On the mechanisms of their construction. This year’s Nobel Prize encourages us to move forward on the path we have already taken through our research. “
Editor’s note: Following last year’s prizes, we started discussing prizes. The end result was that we decided to do quick coverage on the day of the awards and check to see if there were any aspects of the work that matched the deeper coverage that could happen later. So far, we haven’t seen anything about this year’s Physics Prize that suggests more detailed coverage would be informative for our readers.
