Not All Theories Can Explain the Gargantuan Black Hole M87*

Black Hole Anatomy

This artist’s impression depicts a rapidly spinning supermassive black hole surrounded by an accretion disc. This thin disc of rotating material consists of the leftovers of a Sun-like star which was ripped apart by the tidal forces of the black hole. The black hole is labeled, showing the anatomy of this fascinating object. Credit: ESO

Scientists at Goethe University Frankfurt and the Event Horizon Telescope Collaboration use data that produced the first image of a black hole to constrain its fundamental properties.

Theoretical physicists at Goethe University Frankfurt have analyzed data from the black hole M87* as part of the Event Horizon Telescope (EHT) collaboration to test Albert Einstein’s theory of general relativity. According to the tests, the size of the shadow from M87* is in excellent agreement being from a black hole in general relativity, but sets constraints on the properties of black holes in other theories. In 2019, the EHT collaboration published the first image of a black hole located at the center of the galaxy M87.

As first pointed out by the German astronomer Karl Schwarzschild, black holes bend space-time to an extreme degree due to their extraordinary concentration of mass, and heat up the matter in their vicinity so that it begins to glow. New Zealand physicist Roy Kerr showed rotation can change the black hole’s size and the geometry of its surroundings. The “edge” of a black hole is known as the 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 properties: mass, spin, and a variety of possible charges.

Event Horizon Sizes for Different Theories of Gravity

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

In addition to black holes predicted from Einstein’s theory of general relativity, one can consider those from models inspired by string theories, which 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, which leads to observable modifications in the sizes of black holes as well as in the curvature in their vicinity.

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

The result of these investigations: The data from M87* are in excellent agreement with the Einstein-based theories and to a certain extent with the string-based theories. Dr. Prashant Kocherlakota explains: “With the data recorded by the EHT collaboration, we can now test different theories of physics with black hole images. Currently, we cannot reject these theories when describing the shadow size of M87*, but our calculations constrain the range of validity of these black hole models.”

Professor Luciano Rezzolla says: “The idea of black holes for us theoretical physicists is at the same time a source of concern and of inspiration. While we still struggle with some of the consequences of black holes – such as the event horizon or the singularity – we seem always keen to find new black hole solutions also in other theories. It is therefore very important to obtain results like ours, which determine what is plausible and what is not. This was an important first step and our constraints will be improved as new observations are made.”

In the Event Horizon Telescope collaboration, telescopes from around the globe are interconnected to form a virtual giant telescope with a dish as big as the Earth itself. With the precision of this telescope, a newspaper in New York could be read from a street café in Berlin.

Reference: “Constraints on black-hole charges with the 2017 EHT observations of M87*” by Prashant Kocherlakota et al. (EHT Collaboration), 20 May 2021, Physical Review D.
DOI: 10.1103/PhysRevD.103.104047

25 Comments on "Not All Theories Can Explain the Gargantuan Black Hole M87*"

  1. Howard Jeffrey Bender | May 24, 2021 at 11:53 am | Reply

    While everyone is focused on supermassive Black Holes at the centers of galaxies, another possibility exists. According to String Theory, a brane (dimensional membrane) surrounds our universe. What if such branes, rather than Black Holes, are also the centers of galaxies? Superheated gas would also form around branes, and they would explain how the matter in the universe became concentrated as galaxies even as the universe was, and still is, flying apart from the Big Bang at a rate that absolutely won’t allow any matter (quarks, even) to gravitationally attract each other to form anything. It would also explain those low-mass stars at the center of the Milky Way and the Andromeda galaxy, and other curious phenomena seen at those centers. How would we know if the center is a Black Hole or a brane? If material (gas, etc.) is seen swirling into the center, it’s a Black Hole. If material doesn’t swirl in, that would be support for a brane. The physical creation of brane-centered galaxies using the quantum foam and similar to Hawking radiation can be described in my YouTube

    • Torbjörn Larsson | May 24, 2021 at 12:53 pm | Reply

      You always say that, even in cases such as the paper – which you should read – generally kills off the string theory proposals (i.e. those with dilaton fields). Also, pseudoscience link.

      The article is “nice” to string theory, but the paper isn’t-

  2. Torbjörn Larsson | May 24, 2021 at 12:49 pm | Reply

    Looks like they can rule out general relativistic extremal black holes, as other observations do, but in general the string theory proposals (with dilaton fields) vastly die.

    It is a nice reference on non-singularity solutions (of which some survives, I believe) – 5 out of 15 types of solutions.

  3. Marin Tomuta | May 24, 2021 at 3:12 pm | Reply

    I’m pretty sure ‘blackholes’ aka ‘darkvoids’ are really just giant stars or code for ’empty space’. Every galaxy obviously has a giant bright energy center spinning/spiralling around due to fundamental attractive forces.
    ‘Don’t stare directly into the SUN, it will blind you.’ And thats how ‘blackholes came to be.
    Schwarzschild tried to understand stelar physics but somehow went down a white rabbit hole.

    Continental Scientists are often politically, economically and nationally motivated. They are not willing to risk being traitors to know the truth.

    • Torbjörn Larsson | May 25, 2021 at 2:42 pm | Reply

      They are called black holes, they are not “voids” but has mass (obviously), spin and charge [ ], and your made up conspiracy theory no one else can do something with so the less we hear about it the happier we are.

      • Marin Tomuța | June 9, 2021 at 2:47 pm | Reply

        Ad hominem.
        I raised a serious issue: deception, tainted by politics, in Science.
        We’re all selfish organisms, so I’ll try to understand.
        Sorry. I don’t want to go down this ‘blackhole’.
        Maybe it a blackwhole, as in darkness of space with few sources of light and matter.

      • Marin Tomuța | June 9, 2021 at 3:45 pm | Reply

        Maybe its true and I’m wrong.

      • Marin Tomuța | June 9, 2021 at 3:46 pm | Reply

        And to be truly objective eye should lose myself too.

  4. Marin Tomuta | May 24, 2021 at 3:14 pm | Reply

    Correction: they are not willing to speak the truth and risk being traitors.

  5. Marin Tomuta | May 24, 2021 at 3:29 pm | Reply

    Ode to the day when Earth Life communicate/cooperate/colaborate as one. 7 virtues vs 7 vices. Female vs male virtues & vices. Interestingly organisms grow up and down.🌞

  6. Marin Tomuta | May 26, 2021 at 1:08 pm | Reply

    They’re not black and theyre not holes. From the looks of it, theyre massive stars.

  7. Marin Tomuta | May 26, 2021 at 1:09 pm | Reply

    Find a hole in outerspace.

  8. Marin Tomuta | May 26, 2021 at 2:06 pm | Reply

    As for conspiracy theories, in general, exist for a reason; if youre not part of the conspiracy, you make up (hypo)theories.

    Putting Politics before Science?

    ‘The Science of Imagination’

    “…black holes cannot exist.”

    “A general acceptance of the possibility of a black hole did not occur until the second half of the 20th Century, and Schwarzschild himself did not believe in the physical reality of black holes, believing his theoretical solution to be physically meaningless.”

    But if you were to say this is part of the study of stellar fusion, collapse and supernovae, it might flow. Or maybe an attempt to siphon off stellar energy.
    Anyways, all the images are animations, artist impressions or visualizations not actual images. And that 1st one seems doctored.
    And the name seems unscientific and unprofessional too.

    If you look at the sun long enough, it will seem like it turned black.
    At the galaxy core is a supermassive star. This may be more about how stars work and what is actually happening at the central point. Or it could be the longest running prank science.
    Why not call it a ‘darkvoid’? Its synonymous with ‘blackhole’. Why not call it a vortex or whirlpool? I might be wrong though, thinking of hurricanes this quantum phenomenon is possible. As to stars, I think its attractive forces that cause mergers.
    So is our galactic supermassive star in danger of going supernovae aka big bang?

  9. Marin Tomuta | May 26, 2021 at 2:41 pm | Reply

    The Science of Imagination

    “…black holes cannot exist.”

    “A general acceptance of the possibility of a black hole did not occur until the second half of the 20th Century, and Schwarzschild himself did not believe in the physical reality of black holes, believing his theoretical solution to be physically meaningless.”

  10. Marin Tomuta | May 26, 2021 at 2:43 pm | Reply

    Conspiracy theories, exist for a reason. If youre not part of the conspiracy, you make (hypo)theories.
    From my view ‘blackholes’ are the conspiracy theory.

  11. Marin Tomuta | May 26, 2021 at 2:50 pm | Reply

    Look at the sun long enough and it will turn black.
    At the galactic center is a supermassive star.
    As to how stars function, I think thats what this is about.
    The term ‘blackhole’ is unscientific, unprofessional, archaic and fictitious.
    Why isn’t it called a vortex, whirlpool or space hurricane?
    All the images are visualizations, artist impressions or depictions. Even that 1st ‘picture’ seems doctored.

    I dislike this competitive MO in Science, but keeps things moving and verifiable.

  12. Marin Tomuta | May 26, 2021 at 2:56 pm | Reply

    The Science of Imagination

    The essential result of this investigation is a clear understanding as to why Schwarzschild singularities do not exist in physical reality. In other words, black holes cannot exist.

    A general acceptance of the possibility of a black hole did not occur until the second half of the 20th Century, and Schwarzschild himself did not believe in the physical reality of black holes, believing his theoretical solution to be physically meaningless.

  13. Marin Tomuta | May 26, 2021 at 2:56 pm | Reply

    The Science of Imagination

  14. Marin Tomuta | May 26, 2021 at 2:58 pm | Reply

    Work and happiness don’t mix in my world.

    • Marin Tomuța | June 15, 2021 at 10:51 am | Reply

      I’m sorry my friend. Work and happiness when we work for someone or something we dislike, usually simply for their money.
      Enjoy your life. Enjoy your work.🌞

  15. Marin Tomuța | May 27, 2021 at 6:59 am | Reply

    Mr. Larson, I’ve observed that name-calling/projecting is self-reflective & reflexive. Ironic that you brought up the idea of a conspiracy theory b/c thats exactly what I think this ‘blackhole’ hoopla is. Sorry to have burst your happyness bubble; I’m sure you can find it again in something more real and less mysterious.
    Sorry for the repetetive entries.

  16. Marin Tomuța | May 27, 2021 at 5:29 pm | Reply


  17. Marin Tomuța | May 28, 2021 at 9:39 am | Reply

    *Larsson. And apollogy for getting personal.

  18. Marin Tomuța | June 3, 2021 at 10:57 am | Reply

    Maybe instead a ‘blackhole’ or ‘dark matter’ the center of stars and galaxies are composed of heavy matter, aka heavy elements in a high density state: plasma or highly concentrated plasma being formed from high pressure interactions. (Galactic cores would have more in higher concentrations than stars, obviously.)
    If its hypotheisized that Earth has a molten/liquid iron core, why wouldn’t the Sun have a plasmic iron core? Or maybe even higher protonic elements in high temperature & high pressure forms. The heavy elements with high pressure & temperature could be what gives each star its massive gravitational pull.
    And so for the galactic core (a more massive star) it might have even heavier elements concentrated in even more densely organized structures at higher pressures & temperatures, thus causing even greater gravitational pulls strong enough to pull billions of stars along/around.
    Basically scaling up the Earth model but with unique star/galactic details.
    Or maybe the galactic center produces hydrogen or subatomic particles from quarks; as the sun produces helium (atomsphere) and heavier elements (core) from hydrogen.
    The Causmos seem to be self sustaining; stars and galactic centars self-regulating: a heavier/denser core that holds them together and a reactive atomsphere.

  19. Marin Tomuța | June 5, 2021 at 11:52 am | Reply

    If the sun builds elements as big as Iron in its core, it logically follows that bigger stars build bigger elements in their core and so supermassive stars at the center of galaxies builds even bigger/heavier elements, perhaps like the ones that last only nanoseconds here on Earth.
    Perhaps this also explains why some heavy elements are unstable and break apart. They are not fused well enough stabely inside star cores.
    So doesn’t that make more sense then this unscientific, unprofessional and uncivil ‘blackhole’ conspiratorial racingist & sexist nonesense?

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