Einstein’s Theory of General Relativity Tested by Black Hole Shadow


The simulation of the M87 black hole shows the motion of the plasma as it revolves around the black hole. The bright thin ring that can be seen in blue is the edge we call the black hole shadow. Credit: L. Mediros; C. Ease; D. Psaltis; F. Özel; UArizona; Indian Administrative Service.

Einstein’s description of gravity was just so hard to beat that astronomers kept general relativity for a new test Black hole Images.

Einstein’s theory of general relativity – the idea that gravity is matter that is prolonging the duration of war – has been overcome by more than 100 years of investigation and testing, including the latest test from the Event Horizon telescope collaboration, which is today Has been published in the latest issue of. Physical review letter.

According to the findings, Einstein’s theory was just 500 times harder to beat.

Despite his successes, Einstein’s strong theory remains mathematically irreversible with quantum mechanics, a scientific understanding of the sub-atomic world. The test of general relativity is important because the ultimate theory of the universe must include both gravity and quantum mechanics.

“We expect a complete theory of gravity to be different from general relativity, but there are several ways that it can be modified. We found that whatever is the correct theory is significantly different from general relativity when it comes to black holes. Can’t be. We’ve really squeezed the location of possible modifications, “said Dimitrios Saltalis, a professor of Arizona astrophysics who was most recently the project scientist for the Event Horizon telescope collaboration. Psaltis is the lead author of a new paper by researchers Details the findings.

“This is a new way to test general relativity using a superactive black hole,” said Keichi Asada, a member of the EHT Science Council and an expert on radio observations of black holes for the Academia Sinica Institute of Astronomy and Astrophysics.

Black hole shadow test

Visualization of new gauges developed to test predictions of modified gravity principles against measurement of M87 shadow size. Credit: d. Saltaltis, Euerijona; EHT Support

To test, the team used the first image of a supermassive black hole in the center of the nearby galaxy M87, obtained with EHT last year. The first results showed that the size of the black-hole shadow was consistent with the size predicted by general relativity.

“At the time, we were not able to ask the opposite question: how different can a gravitation theory be from general relativity and still correspond to shadow shape?” Said Pierre Christian, a Uriarizon Steward Theory Fellow. “We were surprised what we could do with these comments, if there were some alternatives.”

The team performed a very comprehensive analysis of several modifications to the theory of general relativity to identify the unique feature of the theory of gravity that determines the shape of a black hole shadow.

Lia Medeiros as a postdoctoral fellow at the Institute of Advanced Study said, “This way we can now infer whether there is an alternative to general relativity with the Event Horizon Telescope observations, without worrying about any other details . ” EHT collaboration from her time as a UriJona graduate student.

Strength of gravity

Illustration of various forces of gravitational fields investigated by cosmological, solar-system and black-hole tests. Credit: d. Saltaltis, Euerijona; NASA / WMAP; ESA / Cassini; EHT Support

The team focused on the range of options that had undergone all previous tests in the solar system.

“Using the gauge we developed, we showed that the measured size of the black hole shadow in the M87 tightens the wiggle room by about 500 to a modification in Einstein’s theory of general relativity compared to previous tests of the solar system.” Fearl Ezell, professor of astrophysics at Urijona, is a senior member of the EHT Collaboration. “Several ways to modify general relativity fail this new and strict black hole shadow test.”

“The black hole images provide a completely new angle for testing Einstein’s theory of general relativity,” said Michael Kramer, a member of the Max Planck Institute for Radio Astronomy and EHT.

“Combined with gravitational wave observations, this black hole is the beginning of a new era in astrophysics,” Psaltis said.

The test of the theory of gravity is a continuous finding: are general relativity predictions for various astrophysical objects sufficient for astrologers who do not worry about any possible differences or modifications of general relativity?

“We always say that General Relativity passed all the tests with flying colors – if I feel like every time I hear that,” Zel said. “But it’s true, when you do some tests, you don’t see that the results deviate from the general relativity prediction. What we’re saying, while all of that is correct, is the first time we have a different gauge. By which we can do a test that is 500 times better, and this gauge is the size of the shadow of a black hole. ”

Subsequently, the EHT team expects high-fidelity images to be captured by an expanded array of telescopes, including the Greenland Telescope, the 12-meter telescope at Kit Peak near Tucson, and the Northern Extended Perimeter Array Observatory in France.

“When we get an image of a black hole in the center of our own galaxy, we can further constrain deviations from general relativity,” saidzel said.

Will Einstein still be right?

Reference: 1 October 2020, Physical review letter.
DOI: 10.1103 / PhysRevLett.125.141104

The International Cooperation of Event Horizon Telescope announced the image of a black hole for the first time on April 10, 2019 by creating a virtual earth-shaped telescope in the heart of the radio galaxy Messier 87. Supported by considerable international investment, EHT combines existing telescopes using novel systems – creating a new device with the highest angular resolution power that has yet been achieved.

The different telescopes involved in the EHT collaboration are: Atacama Large Millimeter / Submillimeter Array (Alma), Atacama Pathfinder Explorer (APEX), Greenland Telescope (since 2018), IRAM 30-Meter Telescope, NOEMA Observatory (Expected 2021), Kit Pit Telescope (Expected 2021), James Clerk Maxwell Telescope (JCMT), Large Millimeter Telescope (LMT) ), Submillimeter Array (SMA), Submillimeter Telescope (SMT), and South Pole Telescope (SPT).

The EHT consortium consists of 13 stakeholder institutions; Academician Sinica Institute of Astronomy and Astrophysics, University of Arizona University of Chicago, East Asian Observatory, Harvard-Smithsonian Center for Astrophysics, Goeth-Universita? T. Frankfurt, Institut de Radioestronomy Milime? Trike, Large Millimeter Telescope, Max-Planck-Institute Fu? R radiostronomy? MIT Haystack Observatory, National Astronomical Observatory of Japan, Perimeter Institute for Theoretical Physics and Redbod University.