back to article We've seen things you people wouldn't believe. A halo of light polarized by a gigantic black hole's magnetic field...

Astronomers have captured the most detailed image yet of a supermassive black hole, demonstrating at an intimate level how its magnetic field polarizes light from the phenomenon. The first-ever direct image of a black hole, unveiled in 2019, showed the silhouette of the giant 6.5-billion-solar-mass void at the center of M87, a …

  1. Conundrum1885

    Can you still

    hear the electrons screaming, Clarice?

    Sound of particles spiraling in to their doom, in the dark maw at the centre of our Galaxy.


  2. RM Myers
    Thumb Up

    This article is a good reminder to us all

    that endless video conferences in the age of coronavirus are not the only things which can warp the very fabric of space and time.

    BTW, also some very good work in the field of radio astronomy.

  3. Potemkine! Silver badge

    I watched a documentary recently on how the first picture of that black hole was taken. The technicity for the synchronization of the different telescopes across the world is amazing. So was the pressure on the IT guys to get algorithms able to reconstruct the data ^^

    Congrats to the team, they made an absolutely outstanding work.

  4. Anonymous Coward
    Anonymous Coward

    "The team believes the field keeps the halo of plasma together, and counteracts the black hole’s gravitational field"

    So either a) magnetic directly pushes against gravity as if they're not fundamental forces, or b) light (or your photons) and or matter, is internalizing the two forces without being ripped apart somehow, or c) magnetic is countering the compression of space time.... to stretch it, in some sort of blah blah blah way....

    Can I point out, that you can split a photon with nothing but a few slits, so it isn't internalizing the two b) is not correct.

    You've never made a claim, that magnetic bends space time, let along stretches it, so c) is out.

    That leaves a), gravity isn't a fundamental force.

    I walked you through that conclusion a different way a few days ago, here it is again.

    And I walked you through why that implies there are no neutral fundamental particles, and why the photon isn't therefore fundamental.

    1. Chris G Silver badge

      Dunning Kruger

      See title.

      1. Steve Kerr

        Re: Dunning Kruger

        From memory of physics in school 40 years ago, didn't search for this on purpose....

        Where you have a photon generator firing a single photon at a time and 2 slits where the photon can go through you will get an interference pattern


        If you try to identfy the exact slit it goes through, the interference pattern will disappear as the very act of viewing which slit the photon goes through affects the outcome.

        Something to do with it both being a wave and a particle from memory.

        I do also recall reading that with quantum entanglement, it is possible to identify which slit the photon went through and keep the interference pattern.

        Kudos though for the science and everything that went through to finding this stuff, I absolutely love reading about these things.

        1. Anonymous Coward
          Anonymous Coward

          Re: Dunning Kruger


        2. aregross

          Re: Dunning Kruger

          I've always thought that you are only seeing it go through one slit or the other because we can only see the harmonics of the photon's fundamental frequency. I dunno, It's the only thing that make sense to me.

      2. Anonymous Coward
        Anonymous Coward

        Re: Dunning Kruger

        Yes, sadly something like that.

        1. Conundrum1885

          Re: Dunning Kruger

          Entanglement has been demonstrated with antimatter as well.

          1. Anonymous Coward

            Re: Dunning Kruger

            Certainly has, since photons are their own antiparticles! (I know this isn't what you meant...)

    2. Anonymous Coward

      Here's the thing. I'm standing on the floor. Gravity is pulling me down, but mysteriously I am not in free fall in an orbit around the centre of mass of the Earth: something is pushing back. That ... doesn't mean gravity is not a fundamental interaction.

      1. Cuddles Silver badge

        Indeed. I've seen a lot of weird physics claims over the years, but "gravity isn't a fundamental force because other forces also exist" has to be a pretty special one.

    3. Pascal Monett Silver badge

      Please point me towards your Nobel Prize-winning PhD thesis that outlines your theory in detail.

      Oh, you're still writing it ?

      I can wait.

    4. Throatwarbler Mangrove Silver badge

      Look, AC, I don't understand quantum physics, but I do understand English. From a logical perspective, you haven't proven anything. Your words are incoherent gibberish, which suggests but does not prove that your thoughts are also gibberish.

      For example, this paragraph is literally meaningless:

      "So either a) magnetic directly pushes against gravity as if they're not fundamental forces, or b) light (or your photons) and or matter, is internalizing the two forces without being ripped apart somehow, or c) magnetic is countering the compression of space time.... to stretch it, in some sort of blah blah blah way...."

      And no, to forestall your immediate response, the problem is not my lack of understanding; the problem is that you are not explaining whatever you are trying to say in a comprehensible fashion.

      1. Wexford

        Allow me to describe my very amateur theory of gravity as a "probability function".

        My understanding is that gravity warps space, in such a way that it can be considered "compressed" as you approach the object/source of the gravity. Think of that 3d rendering of a gravity well.

        As an "orbiting" electron "disappears and reappears" (I use quotes to describe what we observe but don't fully understand), there is a greater probability of it "reappearing" closer to the source of gravity on account of there being more, because it's compressed, space on that side of its nucleus.

        The nucleus, by way of the strong interaction/force, is then pulled towards the source of the gravity by its electron. At a macro scale, objects thus move towards each other.

        This has been bouncing around in my head for years, but I'm obviously not a physicist, and I've never had a forum in which to suggest this to someone who knows much more than I about such things to see what they think. Which would likely be "you really should have posted this as AC, you idiot".

        1. Cuddles Silver badge

          "The nucleus, by way of the strong interaction/force, is then pulled towards the source of the gravity by its electron. At a macro scale, objects thus move towards each other."

          OK, there are quite a few issues with your idea, but this is probably the biggest one. You're essentially postulating that gravity is an emergent tidal force which only exists due to the difference of some effect on two particles which then attract each other via another force. If this were the case, only composite particles, such as atoms with orbiting electrons, could be attracted by gravity, while individual particles would not be. However, we observe that everything is affected by gravity - protons, electrons, photons, and every other particle we have been able to observe.

        2. Anonymous Coward

          Well, in a way this is right, but it's unfortunately not helpful.

          It's easier to think about, say, footballs, than electrons or atoms or molecules, because they're bigger and easier to visualise: exactly the same rules apply but the numbers are different.

          So, in the absence of gravity at some point you know (approximately) where your football is and also you know (approximately) its velocity. And you want to know where it's going to be later on. Well, how you find that out is to calculate, for each possible place it could be all the possible ways it could have got there (all the paths it could have taken) and for each possible path you compute a (complex) number which is (sort-of) the square root of the probability of it getting there along that path. And you add all these complex numbers, and then square the sum (you multiply the sum by its complex conjugate in fact), and that's the probability of it getting to that place.

          And when you do that you find that almost all of the probabilities are minute (I mean, seriously minute) because the complex numbers all cancelled out, except for a set of them which run along what turns out to be a straight line, depending on how much later you look.

          And so objects travel in straight lines, statistically speaking, and for macroscopic objects the statistics are so compelling that we never realised that there was all this complicated go-all-ways-to-everywhere-and-then-work-out-how-likely-that-was thing going on until we started looking at very tiny objects.

          Well, you can do the same thing in the presence of gravity, and it all works out fine as well. Except now, because spacetime isn't flat, there kind of is more of it near massive objects: in particular the lengths of the paths that you're doing the sum over all get changed by the deformation of spacetime. And so, when you do the sum, you find that, now, the places where the thing is likely to be are different: instead of being along a straight line, they're along a path called a geodesic (which sort-of is the straightest line you can have in a spacetime which isn't flat).

          And so, statistically again, objects now travel along these geodesics instead of straight lines under gravity. And indeed, the geodesics do tend to be nearer to the massive body than they would be if there was no gravity.

          And unfortunately this isn't helpful: because what it says is that if you assume gravity is this deformation of spacetime then this insane sum-over-all-the-ways-of-getting-somewhere approach tells you what you already knew classically: things travel on different paths under gravity (and what those paths are). What you need to do, somehow, is work out how you can get this effective deformation of spacetime from some quantum-mechanical thing without just wholesale importing what general relativity says into your quantum theory, which is what I've done here.

          But nevertheless this idea of things trying all the places they could go is quite important: it sounds insane, but in fact what I've tried to describe above is a (probably botched, certainly simplified) description of a formalism in quantum mechanics called the 'sum over histories' or 'path integral' approach, which has been extremely fruitful in physics (in its mature form it's due to Feynman, although Dirac and others had at least parts of it earlier).

          1. Wexford

            Thanks both for your comments. More food for thought, especially the geodesic idea!

  5. Andy The Hat Silver badge


    "... help us figure out how and why the black hole ejects gigantic jets of radiation and matter from its core."

    Not from its core, from the rotating and infalling material of the acretion disc coaxial with the "poles" of the disc.

    The questions here are how the shape of the magnetic field of the black hole constrains and distorts the rotating cloud of plasma to allow the massive gravitational energy input to and photon/particle output from to the jets to continue in an apparently stable way; is the rotation axis coaxial and stable with the magnetic field axis or is it offset (as Earth's is); is it a simple magnetic field or does it have a weird shape? How does the magnetic field of the plasma itself impact the stability of the acretion disc and jet? Is it a simple torus or does it rotate? So many questions, so little spacetime ...

    1. ClockworkOwl

      Re: Oops

      Well, spiralling charged particles in a magnetic field should cause a few inductance type shenanigans...

      But I'm not falling into that old EU trap, nosireee nothing to see move along. . . . . . .

  6. m4r35n357

    That is . . .

    some beautifully combed hair? [ducks]

  7. Anonymous Coward
    Anonymous Coward

    Needs a longer baseline

    Like Earth, L1, L2, L3, L4 ... should be able to image the Rocinante

    There's a slight issue with getting the disks back, but that's just a technicality.

  8. Archivist

    Thanks for publishing this article

    It shows that the technology around us can be put to a better purpose than spreadsheets and funny cat videos.

    1. ThatOne Silver badge

      Re: Thanks for publishing this article

      Well, money talks, and when money talks, everybody else shuts up. To (mis)quote Monty Python, "What has science ever done for me?"...

  9. Anonymous Coward

    Black hole in 'has quite mundane magnetic field' shock!

    So I was all set up to point out that some error involving missing out large powers of ten had been made in the article's quoted magnetic field strengths. But no, it's just not that strong: it's perhaps a few times ten stronger than Earth's, but not the 'absurdly stronger' you'd naïvely expect.

    1. Yet Another Anonymous coward Silver badge

      Re: Black hole in 'has quite mundane magnetic field' shock!

      And because the signal took so long to get here they are still in Gauss rather than Tesla

      1. Anonymous Coward
        Anonymous Coward

        Re: Black hole in 'has quite mundane magnetic field' shock!

        Ford Model T ... /that/ long ago.


    2. Grikath

      Re: Black hole in 'has quite mundane magnetic field' shock!

      To be fair...

      The field only has to accelerate the plasma up to ~c to avoid the event horizon in an orbital equilibrium. And the plasma can have quite a bit of a run-up to get there, especially in a spiral setup. It doesn't have to race around a tight corner like in the LHC or your typical fusion reactor as well, locally the field is "forward only".

      So you can get quite a lot done with a "modest" field.

      1. Anonymous Coward

        Re: Black hole in 'has quite mundane magnetic field' shock!

        Yes. Although it has to be well outside the event horizon of course (3x Schwarzschild radius for a non-spinning BH, more complicated for Kerr).

    3. Cuddles Silver badge

      Re: Black hole in 'has quite mundane magnetic field' shock!

      That's one of the fun things about space stuff. Most of the time most of the numbers aren't that big or unusual. It's just that the one number that usually is really, really big is size. A magnetic field about as strong as the Earth's doesn't seem particularly impressive. A magnetic field about as strong as the Earth's that extends for nearly 5000 light years can yield some quite impressive results.

  10. 89724102172714182892114I7551670349743096734346773478647892349863592355648544996312855148587659264921 Bronze badge

    Gosh I hope that the hypothetical Planet 9 really is a tiny black hole...

    1. Grikath

      Well.. The science says that a theoretical black hole of the mass P9 is supposed to have would evaporate ( or explode, depending on your taste ) within nano- , if not femtoseconds after creation. With an event horizon so small that single atoms seem large in comparison.

      Not exactly a likely candidate.

      1. Anonymous Coward

        It doesn't say that, in fact. For a black hole to be in thermal equilibrium with the cosmic microwave background its mass needs to be about 0.6 of the mass of the Moon. Anything more massive will be gaining mass from the CMB, so even if it is not accreting any other mass at all (for instance if it's in some distant bit of intergalactic space) it will still be be (very slowly) gaining mass, and will continue to do so until the temperature of the CMB drops far enough, which will be a very long time indeed for anything of planet 9's theorised mass (5-10 times the mass of the Earth).

        The problem with black holes this light is not that they'd evaporate: it's that there's no mechanism we know of that starts with anything that isn't one and ends up with one. So if they exist they are assumed to be primordial – they originated in the big bang. Such objects were one of the candidates for dark matter in fact, so people have spend a lot of time looking for them using gravitational lensing, and we know as a result that there are not that many of them. One nice idea is that we can further lower the bound on their numbers by looking for them in the outer Solar system: if they're there there will be accretion events which should be visible. That's where the whole 'Planet 9 might be a primordial BH' thing comes from I think.

  11. yogidude

    Charge separation in a black hole

    In a plasma by definition there is charge separation. Monopole magnetic fields do not exist in the known universe, the field is always a dipole and requires circulating currents. Circulating currents require charge separation, however small the electric field, a current implies moving or unbound charges. So if a black hole is generating a magnetic field where are the moving charges? If light can't escape a black hole does a black holes magnetic field come from inside the event horizon?

    1. yogidude

      Re: Charge separation in a black hole

      Further to the above mental rambling, from the point of view of looking toward/at a black hole, the farthest one can see is the event horizon. At the event horizon time has stopped from an observers point of view. All the stuff that has ever fallen toward the black hole is jammed up together, moving slower and slower the closer it gets to the event horizon. If there are any magnetic fields being generated by moving charges would they be in that wad of almost unmoving almost timeless stuff near the event horizon.

    2. Anonymous Coward

      Re: Charge separation in a black hole

      If you believe the no-hair theorem (which is uncontroversial I think), then I think a non-charged black hole (which is all BHs in practice) really can't have an intrinsic magnetic field.

      So then there's a problem as to how these possibly-very-intense fields arise. I think the answer is that it's clear they arise outside the horizon, but that the exact mechanisms are not well-understood. Things which can look close to the horizon – like the EHT – are probably helping with this.

      I think the broad outline, though, is that the BH is accreting matter, which means that, because the infalling matter has angular momentum it ends up orbiting the BH, and because it needs to lose a huge amount of energy as it spirals in it gets extremely hot (basically losing energy by crashing into all the other infalling matter – friction really). So as you get close to the BH you get this awful mass of extremely hot stuff screaming around it as it slowly spirals in, ultimately at a significant fraction of the speed of light (I'm not sure what the orbital velocity is at the innermost stable orbit, but a lot). As it gets hotter it gets increasingly dissociated, so you've really got a mass of very hot plasma orbiting the BH. And the fields arise in this stuff, but (repeating what I said above) I believe that the exact mechanisms are not that well understood because it's so hard to observe what is happening.

      (But note: I'm way out of date on this.)

  12. Conundrum1885

    Re. EHT

    Didn't they use PS3's back in the day to simulate colliding black holes?

    AFAIK they had to get special permission from Sony to use CFW on them and hand back key components so they could never again be used as a

    games console, also to reduce power usage and permit consoles to run at >100% GPU load.

    Also recall that the PS4 can be used in this way though required getting dev kits ($$$$) and cloning the Flash chip(s) from one with Sony's permission then signing it with the root key and console key etc.

    Think twoof their techs showed up with a magic box (tm) to do this for them and check that they'd set up everything right.

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