The black hole catches the eyes of the whole world



or Laura García Oviedo (communication area of ​​the Balseiro Institute).

The first image of the black hole obtained through the Event Horizon Telescope (EHT) project is accelerating the media and social networks on Earth. Citizens, as well as scientists, admire and admire. In the field of communication and the press of the Balseiro Institute, we were consulted by four physicists or graduates of the Balseiro Institute and astronomers from the University of La Plata to learn their impressions. Apart from Juan Martín Maldacene, who is participating in this message from the United States of America, all other CONICET researchers do this from their places of work in Bariloche and La Plata.

The achievement of the first "photograph" of the black hole is the result of a team of 200 scientists from different countries. This contribution at the same time represents a new confirmation of Alberto Einstein's theory of general relativity. The announcement, which was announced at the six press conferences that were held simultaneously on Wednesday, April 10, also coincides with the anniversary. 100 observational confirmations of Einstein's theory of predictions.

What are black holes? These are objects that, with their enormous concentration of mass, bend space-time so that everything that is close is subject to its "feasibility", including light. Therefore, the image presented to the world actually showed the shadow of this boundary between the exterior and the interior of the black hole, which is called the horizon of events.

The black hole concerned was spotted in the center of the Messier 87 (M87) galaxy, in the Device constellation, 55 million light-years from Earth. The mass is 6,500 million times the mass of the Sun to observe it, so we used a global network of eight telescopes that were deployed in various places on the planet Earth, which together form the Event Horizon Telescope. Antarctica, the desert of Atacama (Chile), Sierra Nevada (in Spain), Mexico, Hawaii and Arizona (United States) were selected places, the European Commission says.


Before discussing what they predicted this milestone of astrophysics, he was one of the first to respond by e-mail, Juan Martín Maldacena. "It's interesting that they managed to create an image and agree with the expectations of a black hole," says Maldacena, who graduated from the Faculty of Physics at the Balseiro Institute and is a professor at the Princeton Institute for Advanced Studies

Physicist and amateur astronomer Guillermo Abramson, who is a graduate and teacher of Balseira, says: "This is a sensational achievement of theory, computing and radio astronomy. For centuries we have dreamed that these black holes existed, dreamed and calculated with our theories, and we had indirect evidence of their existence, but we have never seen a shadow of a horizon of events that should exist. Of course, it was extremely difficult to see whoever did not calculate, maybe he does not have a complete idea of ​​trouble to see something so small and so far. "He also points out that the observed image perfectly matches the previous simulations, but at the same time it is different from the illustrations that were previously broadcast by the media. And this is the beginning of a new branch of radio astronomy.

For Anahí Granada, an astronomer from the National University of La Plata and researcher CONICET at La Plata Institute of Astrophysics (IALP), this achievement is crucial. "It seems fascinating, not only because of the discovery itself, but because of the tremendous work that was responsible for the restoration of this image. And all the information that needs to be recovered from observations must be learned much more," he stressed.

On the other hand, Diego Harari, a physicist from the Particles group and Fields Atomic Center in Bariloche and Balseira's teacher, emphasizes the "photogenicity" that turned out to be a black hole M87. "There is a lot of circumstantial evidence that there are very large black holes in the center of almost all galaxies. This picture may be the most direct confirmation. You can not see the black holes, but in this picture, we see the light that happened as close as possible, "says researcher CONICET. He points out that what will undoubtedly be learned from these objects with images of even greater resolution in the future, will explain in greater detail how these black holes increase the emission of large "jets" of substances in active galaxies.

His colleague from the same research team, Diego Mazzitelli, notes that an exceptional and incredible technological achievement is that the shadow of the black hole of the galaxy was observed, which is approximately 50 million light-years away. "From the point of view of physics, this is another very important confirmation of the theory of general relativity. An interesting detail is that the light shadow produced by the black hole produced a shade of approximately 2.5 times its size, "says CONCET researcher. He adds: "Since the size can be estimated by means of gravitational effects, the shadow observation is additionally confirmed by the gravitational deformation of light, which Eddington first spotted a hundred years ago."


The worldwide publication of this scientific and technological achievement was accompanied by the publication of a series of six scientific articles or articles in The Astrophysical Journal Letters. One of the representatives of the international group EHT, Heino Falckle, Radboud University of Belgium and EHT scientific adviser, said that the observation hole in the M87 galaxy was submerged in a very bright area. That is why this black hole created a dark area that is similar to the "shadow" generated by the gravitational curvature and the capture of light by the event. All this was achieved through team work.

So why is it so important in astronomy and astrophysics, as well as in other branches of science and technology, to carry out international cooperation? This question was posed to the five scientists who participated in this message. "In this case, it is important that cooperation has been established, since radio telescopes are needed, which are quite separate from one another," says Juan Martín Maldacena.

"In order to observe such a small object, I think small in the sky, because it is far away, although the black hole is a giant like seeing thousands of miles away, you need a telescope of the size of the Earth. For this reason, this could only be achieved through this cooperation. how to do it. Can they achieve a better resolution, a "more focused" image? Certainly using smaller wavelengths and space telescopes. Can you imagine, with a radio telescope on the Moon? ", says True Abramson, who is also a popular scientist and publishes its astronomical blog (

Astrophysicist Bariloche Anahí Granada notes: "The discoveries, such as this, can not be accomplished by some scientists or even one country. Since instruments that are found in different parts of the planet need to be used and many human resources are needed for observation, processing, calibration and analysis data can only be approached with this kind of international cooperation with such an ambitious project. Joint efforts enable the revival of existing knowledge.

For Diar Harari, who holds a Doctorate in Physics from the UBA and co-authored with Mazzitelli on the book "100 Years of Relativity" (Eudeba), he is a spectacular scientific and technological achievement to achieve the necessary angular resolution in order to achieve this. "It's like being able to read the patent of a car on the moon from Earth, which was possible by combining telescopes around the globe, a valuable example of international cooperation. In this case, do not build an instrument whose cost and complexity goes beyond what a country can it does it individually, but unites, in a non-trivial way, the use of existing instruments, "he says.

Mazzitelli, who is the Professor of General Relativity at the Balseiro Institute, adds: "It is also interesting that in a few years there were independent approvals of the theory of general relativity, which were expected for a long time: in 2016, she conducted a direct observation of gravitational waves, now there is direct observation of the black hole, in both cases there was only indirect evidence with its gravitational effects. In both cases, more detailed observations in the coming years will give a lot of information on intensive gravity fields.


Following observations in April 2017 in a ten-day window using a technique called the very long base (VLBI) interferometry, a network of participating telescopes of the EHT project generated a large amount of data. which had to be processed to reconstruct the image of the "shadow" of the black hole M87. The technique used utilizes Earth's rotation for the design of a "large telescope" capable of "observing" radio waves of 1.3 mm, as stated in the EHT press release (see the subtitle "Engineer that went viral networks"). a high angle resolution of 20 microseconds, which would allow a person in Bariloche to read the book in Mexico City in detail.

Many wonder what Albert Einstein would say about this new venture. "I should take the black holes seriously … Because it was thought that mathematical idealizations are of no physical significance," says Maldacena of Princeton, adding that the interesting fact is that the black hole M87 will rotate and that the solution is a black hole Roy Kerr found it in 1963. "This shows that it is not just Einstein's equations, but much later to solve equations and find their physical interpretation."

Both Abramson and Grenada admit they do not know what Einstein would say. "But I would be very happy because what you see is exactly what you would expect," notes Abramson. Granada says: "With this finding, I would be very pleased to see how the scientific community can come together in order to achieve the goals that it seemed impossible to achieve only recently."

"Probably Einstein would be surprised that 100 years later he continues to check the predictions of his theory and that there are no observations that would require a change. Already 100 years ago, when observing the eclipse, it was confirmed that the path of light of the stars is very much deviating from the plane lines at the passage near the Sun, "says Harari. And adds:" In the M87 image, this same effect reaches its maximum expression. Light can even circulate around a black hole like the planet. Perhaps Einstein would also be surprised that black holes are a reality and not just a mathematical option in his theory.

Mazzitelli submits to what his colleagues expressed: "At this point, I would like to mention that although the mathematical solution of Einstein's equations describing black holes has been known since 1916 from the Schwarzschild solution, the physical meaning was not clear until In the 1960s, when the significance of the solution was first understood, the name "black hole" with JA Wheeler in 1967 began to be used. So, this discovery is certainly twice as surprising for Einstein, as theoretical progresses followed his death.

Thus, this first image of the "shadow" of the black hole is still surprisingly and fascinatingly circulating all over the world. In it you can see an almost circular black hole, surrounded by the light emitted by the surrounding plasma, in the M87 galaxy. Perhaps this is not a spectacular image, like the one we see in the big films of science fiction in the Star Trek style, but it has a great deal of merit that it is a true image. The first of many, much more.


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