Did the Event Horizon Telescope film the supermassive black hole at Milky Way Sgr A*?

We recall that on Wednesday April 10, 2019, at 3 pm in France,the international teamEvent Horizon Telescope (EHT) led by Shep Doeleman, researcher at the centerastrophysics Harvard-Smithsonian, makes world headlines by publishing the historical image of the suspected supermassive black hole M87*. It is located in the center of the large elliptical galaxy M87 is located at approximately 53 millionlight years in the Milky Way.

We hope to see the image of supermassive black hole the same is believed to be the heart of our Galaxy. With a few mass of 4.3 million and 6 to 7 billion solar masses (M87*) respectively, the theory of total relativity predicts for these stellar events celestial sizes of 25 million and 36 billion kilometers respectively. Considering the distances to the Earth, these compact objects have the same apparent diameters as the order of an apple or golf ball observed from the Earth above the surface of the earth. month.

Jean-Pierre Luminet, director of research at CNRS and Françoise Combes, professor at the Collège de France, talked to us about black holes, especially the large supermassive black holes in the galaxies that are behind the quasars and that affect in the evolution of galaxies. © Hugot Foundation of the College de France

Let us remember that the only thing that defines a black hole is the possibility of identifying the limits of a closed surface surrounding a region ofspace-time to not escape not to break speed of lightwhat is physically known to be prohibited. L ‘state of the object and spacetime below that surface within a black hole is unknown and even if the theory of relativity only implies the occurrence of a singularity at the core of the black hole where the curvature of space-time is infinite and the density of things the same (as shown by the Nobel Prize in Physics Roger Penrose ), we do not know. In fact, the Heisenberg laws of quantum mechanics and Schrödinger reveals to us and describes what it is called the space-time bubblestrongly suggests that nothing like this is likely to happen.

In the end, it may be the things we take for granted black holes in fact the stars are almost as compact, thus behaving in many respects like black holes from the astrophysical point of view, but no horizon of the event really so not black holes as Hawking himself envisioned. It could be superstring ballson graves and even in wormholes !

Unfortunately, this Wednesday, April 10, 2019, there is no image of the supermassive black hole in the Milky Way linked to the famous source. radio Sagittarius A* (Sgr A* for short), is not shown because the data collected by the international network of radio telescopes to make it possible to take a virtual instrument almost the size of the Earth to achieve the power of resolutions requirements for the observations proved to be more difficult to deal with than expected. EHT collaboration researchers, however, continue to capture new data and improve their processing.

So it goes without saying that for more than a week the tension has been rising after an announcement promising us news about Sgr A*.

This is a joint press release from European Southern Observatory (ESO) and theEvent Horizon Telescope (EHT) explaining that on May 12, 2022, thanks to global village and the WWWthere will be an online conference on this topic that can be followed live from 3:00 pm in France.

The conference on May 12, 2022 live. © European Southern Observatory (ESO)

As an introduction to this conference and to try to imagine its content, let us recall what Shep Doeleman meant to the AFP in 2019 “For years I told people we were going to take a picture of a black hole and they told me they would believe me if they saw it. The scientific community expressed a kind of skepticism, which is normal.. If you finally get the proof, if you achieve such a breakdown, you really feel the satisfaction of giving birth to a new field of research.he continued. We are now in the era of high -precision images of black holes. We can make space-time maps for the first time ”. Better, according toastrophysicistalready at that time, his colleagues were working on making a video from the mountains of recorded data. “By the end of the next decade, we will be producing high-quality, real-time movies of black holes that will reveal not only their appearance but their character on the cosmic stage”assured Shep Doeleman.

He also explained that it was precisely because of the strong and chaotic penetration of matter into the central black hole of the Milky Way that we did not yet have an image of Sgr A*. But it also means very precisely that one should get images that show a clear evolution over time. “It takes about a month to circulate the object around the M87*. But for Sagittarius A*, only half an hour is needed. On a night of observation, Sgr A* may change before us “, he added, also explaining that: “It’s possible we’re going to make a pretty raw first film. Actually, more than that telescopeson Earth or on orbit yutan-on, to increase resolution. But we will improve it over time. It will be like the first movies in theaters ”.

Finally, remember that this is the French astrophysicist and cosmologist Jean Pierre Luminetas he explains many times and with much detail in the versions France and English on blog which Futura made available to him, which was the first in the late 1970s to be calculated computer the visual appearance of a black hole surrounded by a accretion disk. With his partner Jean-Alain Marck, he performed simulations showing the shape of such an object from multiple angles and so we can assume that we can make comparisons between M87* and Sgr A* that should not be presented under the same orientation. eye in the noosphere.

A numerical simulation based on calculations of the total relativity of the shape of a black hole surrounded by a hot accretion disk. It was created by astrophysicist Jean-Alain Marck in 1991. Extract from the documentary “Infiniment curved”. To get an accurate French translation, click on the white rectangle at the bottom right. English subtitles should be visible immediately. Then click the nut to the right of the rectangle, then “Subtitles” and finally “Automatic Translation”. Select “French”. © Authors: Laure Delesalle, Marc Lachieze-Rey, Jean Pierre Luminet. Director: Laure Delesalle. Production: CNRS/Arte, France (1994)

The members of the EHT collaboration will therefore surprise us tomorrow with stunning images of Sgr A*. We can also reasonably expect new limitations in new physics that could replace the theory of relativity inEinstein and of course also the existence or non -existence of an event universe.

Einstein’s theory of general relativity is not the only possible one that is consistent with the theory of Relativity and based on the possibility of space-time curvature. from equations differently reduced to Einstein in some situations as in the case of the equations of Newton borderline cases of Einstein have actually been considered and studied for over 50 years as the famous tensor-scalar theories.

Invalidating Einstein’s theory in favor of these variants would provide us with keys to solving the enigmas associated with black matter and thedark energy. In contrast, supermassive black holes are believed to have an outer space-time geometry that is in a rotating Kerr black hole. This includes actions very accurate for matter and trajectories as accurate as for light rays produced by hot matter on an accretion disk around certain black holes.

If the agreement is good enough between the predictions of Einstein’s theory for a black hole in Kerr and the new observations made by members of the EHT collaboration, then it could lead to the denial of exotic and rather unbelievable alternatives to black hole theory.

Gain an idea of ​​how the observations of Sgr A* can lead to explorations of Einstein’s alternative theories and of solutions to their equations describing alternatives to Einstein’s general relativity by consulting video below already mentions these tests performed with EHT, but for the M87*.

We can estimate the mass of the black hole M87* by studying the movements of the stars around it. The solution of Einstein’s equations with mass M87* refers to the given image and size for the shadow of the black hole’s event horizon. Alternative theories of gravity and different electric charges involve different images with a small size of the event universe, as explained in this video. EHT therefore makes it possible to test new theories of gravitation and the existence of exotic black holes. To get an accurate French translation, click on the white rectangle at the bottom right. English subtitles should be visible immediately. Then click the nut to the right of the rectangle, then “Subtitles” and finally “Automatic Translation”. Select “French”. © BlackHoleCam

To change your memory about the global network of EHT radio telescopes and what it can observe for the so-called shadow (shadow in English) in a black hole, you can watch the video below.

A lengthy presentation of the findings was made byEvent Horizon Telescope in 2019. To get a fairly accurate French translation, click on the white rectangle at the bottom right. English subtitles should be visible immediately. Then click the nut to the right of the rectangle, then “Subtitles” and finally “Automatic Translation”. Select “French”. © European Southern Observatory (ESO)

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