Light Echo From Behind a Black Hole Confirms Einstein’s Theory of General Relativity

Light Echoes From Behind a Black Hole

Illustration of how light echoes from behind a black hole. Credit: ESA

For the first time, astronomers have singled out light coming from behind a black hole, enabling them to study the processes on its far side.

Using ESA’s XMM-Newton and NASA’s NuSTAR space telescopes, an international team of scientists led by Dan Wilkins of Stanford University in the USA observed extremely bright flares of X-ray light coming from around a black hole.

The X-ray flares echoed off of the gas falling into the black hole, and as the flares were subsiding, the telescopes picked up fainter flashes, which were the echoes of the flares bouncing off the gas behind the black hole.

This supermassive black hole is 10 million times as massive as our Sun and located in the center of a nearby spiral galaxy called I Zwicky 1, 800 million light-years away from Earth.

The astronomers did not expect to see anything from behind the black hole, since no light can escape from it. But because of the black hole’s extreme gravity warping the space around it, light echoes from behind the black hole were bent around the black hole, making them visible from XMM and NuSTAR’s point of view.

Light Echoes From Behind a Black Hole

Animation showing how light echoes from behind a black hole. Credit: ESA

The discovery began with the search to find out more about the mysterious ‘corona’ of the black hole, which is the source of the bright X-ray light. Astronomers think that the corona is a result of gas that falls continuously into the black hole, where it forms a spinning disk around it – like water flushing down a drain.

This gas disk is heated up to millions of degrees and generates magnetic fields that get twisted into knots by the spinning black hole. When the magnetic field gets tied up, it eventually snaps, releasing the energy stored within it. This heats everything around it and produces the corona of high energy electrons that produce the X-ray light.

The X-ray flare observed from I Zwicky 1 was so bright that some of the X-rays shone down onto the disk of gas falling into the black hole. The X-rays that reflected on the gas behind the black hole were bent around the black hole, and these smaller flashes arrived at the telescopes with a delay. These observations match Einstein’s predictions of how gravity bends light around black holes, as described in his theory of General Relativity.

The echoes of X-rays from the disk have specific ‘colors’ of light and as the X-rays travel around the black hole, their colors change slightly. Because the X-ray echoes have different colors and are seen at different times, depending on where on the disk they reflected from, they contain a lot of information about what is happening around a black hole. The astronomers want to use this technique to create a 3D map of the black hole’s surroundings.

Another mystery to be solved in future studies is how the corona produces such bright X-ray flares. The mission to characterize and understand black hole coronas will continue with XMM-Newton and ESA’s future X-ray observatory, Athena (Advanced Telescope for High-ENergy Astrophysics).

For more on this discovery, read Strange Black Hole Discovery Confirms Einstein’s Theory of General Relativity.

Reference: “Light bending and X-ray echoes from behind a supermassive black hole” by D. R. Wilkins, L. C. Gallo, E. Costantini, W. N. Brandt and R. D. Blandford, 28 July 2021, Nature.
DOI: 10.1038/s41586-021-03667-0

19 Comments on "Light Echo From Behind a Black Hole Confirms Einstein’s Theory of General Relativity"

  1. I seen General Relativity referred to by one science writer as “dogma”. It is not. It is science and the most proven cosmology theory ever. Just because it continues to be proven now for over 100 years in myriads of ways is not indication of “dogma” but rather “proven”. Nothing wrong with that.

  2. Alex Stewart | July 31, 2021 at 5:34 pm | Reply

    After Carlos Frenk saw that new map of the universe much more smoother all around that it should have been according to Einstein concept of gravity he said he was “frightened” that all his life’s work on expanding of Einstein famous theory might have been wrong after all…And now here this article claims Einstein theory was “confirmed”; but yet other physicists said that because of particles’ entanglement (being at two places at once) there is no real a gravity field , so Einstein must be wrong but then….Who knows what next?.It all looks like a lot of believing but in scientism…

    • 2 theories can be true and still appear to contradict each other. There are many paradoxes observed in life, it’s only when understand the rules that govern both that we can see the whole picture. We don’t have have a unified theory for General Relativity & quantum physics yet. But the prospect of finding one is incredibly exciting!

    • Torbjörn Larsson | August 1, 2021 at 8:20 am | Reply

      The lament on smoothness likely refer to the old Big Bang models where you expect inhomogeneities (i.e. O(1) fluctuations) while the current inflationary hot big bang models explains why we see smoothness (i.e. O(10^-5) fluctuations) in the cosmic microwave background – but they are both general relativistic so called FLRW models.

      As other comments touch, in general [sic!] relativity has been experimentally confirmed to ever increased precision – the sign of a successful theory – for a century now. The same physicists that look at inconsistencies likely most accept general relativity.

      If you want to study entanglement and quantum particles, you switch to effective quantum field theory – special relativity of quamtum field theory gives you realistic particles and general relativity gives you interesting particles (with a ‘better’ mass concept than the Standard Model of particles, may make cosmological structures). In effective quantum gravity theory you can for example entangle massive particles as in other field theory.

      It is funny you should go there, because I have started to assimilate the recently dead Nobel Laureate Steven Weinberg summar of his views [ ]. He was one of the architects not only of the Standard Model but also of effective quantum field theory and was productive throughout. On gravity he says:

      “Similar remarks apply to gravitation, which I think has led to a new perspective on general relativity. Why in the world should anyone take seriously Einstein’s original theory, with just the Einstein–Hilbert action in which only two derivatives act on metric fields? Surely that’s just the lowest order term in an infinite series of terms with more and more derivatives. In such a theory, loops are made finite by counterterms provided by the higher-order terms in the Lagrangian. This point of view has been actively pursued by Donoghue and his collaborators.”

      You can look up Donoghue’s article on effective gravity on Scholarpedia and that it describes general relativity thus far, it isn’t only Weinberg that has noticed it. (He refer to another Nobel Laureate Frank Wilczek – which encompass it in his Core Theory based on Feynman integrals – for instance.) I think the derivatives – who are defined over volumes by the way – are first order as decided by being used in inertial (free fall) frames. So perhaps the field corrections goes both ways – general relativity is after all a classical approximation to what should be a quantum field. (And there are more known inconsistencies such as that general relativity do not approximate special relativity uniquely as you asymptote to flat space.) The problem comes if you want to keep the classic theory untouched as you go quantum – effective quantum field theory is nothing but corrections. “Everything not forbidden is compulsory.”

      The philosophism cheap shot at science which is “scientism” shots back in their faces, since philosophy has failed to produce a single correct descriptive fact of nature despite 3 millennium of existence. Of course science is the only way to knowledge: now we know that and won’t forget.

  3. Ricardo Mota Gomes | July 31, 2021 at 7:44 pm | Reply

    São vislumbres concretos à luz do desenvolvimento técnico-científico que apontam para a iminência do surgimento de Novas Físicas que batem às portas do conhecimento humano contemporâneo✨💫 !!! … 🙌🏻🙌🏻🙌🏻🙌🏻🙌🏻🙌🏻 !!! … 👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻 !!! … 👏🏻👏🏻👏🏻👏🏻👏🏻👏🏻 !!! …

  4. Why do they say 1,800 million light years instead of 1.8 billion light years?

    • I Zwicky 1 is the name, it is 800 million light years away. It’s just a poorly structured sentence that makes it look at though it says 1,800 million.

  5. Quantum entanglement absolutely does not disprove relativity as stated by someone in the comments. Just because quantum mechanics and relativity have yet to be unified (other than super string theory). Both theories are the most successful scientific theories of all time and are absolutely confirmed time and time again. The elusive theory of everything doesn’t mean that without it, all other theories cease to match reality as they clearly do.

  6. Isn’t it about time to change the “Theory of Relativity” to the “Law of Relativity”? Continues to amaze me that Einstein had only his mind and a pencil.

    • Torbjörn Larsson | August 1, 2021 at 8:37 am | Reply

      Special relativity is “a law” in the old sense – mind that the term is dated. General relativity is rather a metalaw since it aims to conserve physics between different observers.

      [I’m just surfacing after the deeep dive that Weinberg put me on. It’s worse than his selection bias multiverse successful prediction of the cosmological constant.

      If I take the simplest possible start with Wilczek’s core theory – Donoghue’s effective quantum gravity field theory- à la Weinberg I get a Minkowski flat universe of special relativity and at the very least total energy conservation from the Lagrangian/Hamiltonian formulations. There is some madness in this, since the consequences are … well, arguable.

      Dunno about the few general relativistic efforts to mop that up but in general it seems they come to the same conclusion I did – general relativity embodies a law that conserves energy by way of Einstein’s equations. That’s just before you seem to touch the fringe … but the equations are legit even if the intended applications are sketchy. C.f. .]

  7. Torbjörn Larsson | August 1, 2021 at 7:48 am | Reply

    I can point to the other SciTechDaily article where I commented some references in context (earlier reverberation candidates, the Blandford et al models of the outer, non-opaque thin accretion disk) : .

  8. Joselito B. Maciel | August 1, 2021 at 5:25 pm | Reply

    The Spin is only explained when one makes relativistic correction of the wave function (Dirac equation), so I consider that Relativity and Quantum theory complement of each other. I even would say they are unified.
    *For those that say Relativity and Quantum theories are not unified.

  9. This is all cartoons and non reality. The Earth is flat completely flat. If we don’t start to understand how badly we’ve been hoodwinked by the globalists pushing the globe we will never stop there Great Awakening again. They’ve done this all before all our history is just BS. Try to prove the ball Earth. If you can let me know I’m still trying. Funny how we’re never taught to question it after they cram it into our heads at Young ages. We are completely programmed. When they started with the movies back when they were programming us all we seen was the spinning ball before they even said they could prove it. They were still teaching Flat Earth in 1930. Just think about it the Stars I’ve never changed

  10. Sf. Ramon Careaga, founder EPEMC | August 3, 2021 at 10:12 am | Reply

    Once again they see NORMAL behavior of a plasmoid and refraction and extrapolate all kinds of nonsense out of it about nonexistent black holes. Bottom line is that Gen Relativity works because of electromagnetism not Gravity. Gravity is remnant electromagnetism. If GR was reworked it would get a lot better results. So far the results are underwhelming. You can expect light to bend around the plasmoid center. Now show me macrolenaing at 3R around a star. You won’t find any cases.

  11. hello spiral galaxy l zwicky 1
    are u facing me horizontally edge on xy
    are u facing me vertically xz
    are u facing me obliquely yz
    and a timeline of 830,000,000 and 1 minute 40 seconds years ago
    and a timeline of 800,000,000 years ago
    welcome to planet earth
    with a black hole black hole 30,000,000 kilometres diameter
    like the eye of the hurricane nothing in your centre
    all of 30,000,000 kilometres diameter absolute nothing
    but your corona 60,000,000 kilometres height above black hole producing bright flares of x rays light with a 30,000,000 kilometre empty core
    and at the circumference of the corona 30,000,000 swirl facing earth your bright x ray flashes chase across space 800,000,000 years ago in a straight line and reaches us here
    and the 60,000,000 corona peaks and troughs of swirling mass has gaps in it along its height windows that allow me to see to the far side of the 30,000,000 kilometres diameter absolute nothing the far side of the circumference
    and these windows allow smaller flashes to travel in a straight line 800,000,000 years and 1 minute 40 seconds across space and time to arrive to mine eyes to record your reflected rays
    thus proving einsteins theory that light travels in straight lines always has always will and always does

  12. I was so amazed at all that science has accomplished. I thought to myself, “Self there has to be a person that doesn’t understand what reality is such as a flag-waving we.”. I need maybe a psycotherapist or maybe one of you science brainiacs can help us understand why people persist in thinking in an alternate reality. Do they have some sort of disorder? Maybe schizophrenia? I will never understand, but it may help me understand why so many refuse to get. The covid-19 vaccine. It would be nice to not wear a mask or stay completely at home because I live in Texas. I surely enjoyed not wearing one. But I do to keep from getting sick and hopefully not infecting another. But to me they both are thinking in a no reality that they in no way can prove their hypothesis at all for they absolutely know nothing about science. Or is it the propaganda the right wing Media is always posting that has no basis in at factual reality. I’m sorry you guys are so kind to simply ignore the person lost 8n a world that lack common simple sense. I wonder do you know if humans go throught periods intermittently where they regress in their intelligence? I’m perplexed and can understand almost what it is you present on a regular basis and it is so fascinating, but 8 can’t seem to understand this reality that seems so crazy especially in politics. I will never understand why something that is painfully obvious is beyond some people’s comprehension. It worries me that m
    People are losing their mental capacity. I hope not. I wish I hadn’t have thought about someone such as a flat earther commenting here. Thank you for allowing me to just ask. I will never understand the things that are happening in the 21st century that I find are completely incomprehensible. Thank you again for your knowledge and sharing. 8 won’t worry about them either. It’s best when it’s hard to explain something that so impossible to explain because it’s so untrue and more of a theory of conspiracy.

  13. Or is it from The Twilight Zone?

  14. This “bent stick in water afect” does not prove Einstein theary at ALL. It proves Einstein a fraud. Xrays are extremely high frequency oscillations (vibrations) in magnetic feilds. Refraction occurs when light passes through powerful magnetic fields.
    Einstein bent time & space to make his theory of reality fit his assumption that gravity “bent” light.
    On Earth, long wave radio (low frequency OSCILLATIONS in magnetic feilds) can be picked up on the other side of the planet.
    If Einsteins theory was correct GRAVITY bent it! Look up for yourselves how it is that long wave radio could be said to “follow the circumference of our Planet”

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