Not all theories can explain the black hole M87 *

All these black holes cast dark shadows distinguishable from each other in size, but only those that fall into the gray band match the M87 * EHT 2017 measurements, and in this image, the one represented in red below. is too small to be a viable model for M87 *. Credit: Prashant Kocherlakota, Luciano Rezzolla (Goethe University Frankfurt and EHT Cooperation / Fixed Film 2021)

As the German astronomer Karl Schwarzschild first remarked, black holes flex spacetime extremely because of their extraordinary concentration of mass, and heat the matter around them so that it glows. New Zealand physicist Roy Kerr has shown that rotation can change the size of the black hole and the geometry of its surroundings. The “edge” of a black hole is known as an event horizon, the boundary around the concentration of mass beyond which light and matter cannot escape and which makes the black hole black. Black holes, theory predicts, can be described by a handful of features: mass, spin, and various possible charges.

In addition to black holes predicted by Einstein’s theory of general relativity, one can consider those of models inspired by string theories that describe matter and all particles as modes of tiny vibrating strings. String-inspired theories of black holes predict the existence of an additional field in the description of fundamental physics that causes observable modifications in the sizes of black holes as well as in the curvature in their surroundings.

Physicists Dr. Prashant Kocherlakota and Professor Luciano Rezzolla of the Institute for Theoretical Physics at Goethe University Frankfurt have now investigated for the first time how the different theories match the observational data of the black hole M87 * in the center of the galaxy Messier 87 The an image of M87 *, taken in 2019 by the international cooperation Event Horizon Telescope (EHT), was the first experimental demonstration of the actual existence of black holes after the measurement of gravitational waves in 2015.

The result of this research: The M87 * data are in excellent agreement with Einstein-based theories and to some extent with string-based theories. Dr. Prashant Kocherlakota explains: “With the data recorded by the EHT collaboration, we can now test different theories of physics using black hole images. Currently we cannot reject these theories describing the shadow size of M87 *, but our calculations limits the scope of validity of these black hole models. “

Professor Luciano Rezzolla says: “The idea of ​​black holes for us theoretical physicists is both a critical and an inspiring source. While we are still struggling with some of the consequences of black holes – such as the event horizon or the extraordinary – we always seem inclined to find new ones. black hole solutions in other theories as well. So it’s very important to get results like ours that determine what’s credible and what’s not. This was an important first step and our boundaries will be improved as new observations are made. “

In the collaboration of Event Horizon Telescope, telescopes from all over the world are joined together to form a virtual giant telescope with a dish as large as Earth itself. With the accuracy of this telescope, a newspaper in New York could be read from a street cafe in Berlin.

Testing Einstein’s theory of gravity of the shadows and collisions of black holes

Additional information:
Prashant Kocherlakota et. al. Limits on black-hole allegations with the 2017 EHT observations of M87 *. Physical Review D … 211e6b42b295ab17d057

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Quote: Not all theories can explain the black hole M87 * (2021, May 20) taken on May 20, 2021 from

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