back to article Black holes are like buses: You wait for one – and three turn up at once in galaxy merger

Astronomers have spied a rare cosmic curiosity: three supermassive black holes appear to be on the brink of merging with one another after a gigantic galaxy collision took place, a billion light years away. The system, codenamed SDSS J0849+1114 for short, is a massive blob of gas and dust born from three separate galaxies that …

  1. jake Silver badge

    That's going to make one hell of a racket.

    I'm glad I'm here and they are there.

    Nice science. Pretty pictures. No politics. Win, win, win.

    1. Brewster's Angle Grinder Silver badge

      Tempting fate.

      "No politics."

      You say that,. But after they've merged, I bet one of them gets all antsy about "losing its sovereignty", changes its mind, and decides it wants to split with the others.

      Seriously. Why is this research funded? Politics. Why are we going back to the moon? Politics. Why can't we emigrate to mars? Okay, that one isn't politics. But you get the drift.

    2. Ian Michael Gumby Silver badge

      @Jake Re: That's going to make one hell of a racket.

      Actually no.

      It will be very quiet.

      You know what they say... its the bullet you don't hear that will kill you.

      In this case... by the time you hear it, you'll be already dead.

      Just saying...

      (Assuming you'll find some way to beat time and still be around in 1 Billion Years)

      1. jake Silver badge

        Re: @Jake That's going to make one hell of a racket.

        Quiet? Really? I rather suspect that finding any kind of signal in such an event will be well nigh impossible, what with all the noise masking it.

        I know I'll probably be long gone by the time it gets here, that's why I'm glad it's there, not here. Of course, what with the inverse square law and all that, in this particular case it probably won't be an issue to whoever is here ... not even if it decides to toss a relativistic jet our way.

        (If I'm not here in 1 billion years, it's only because I died trying.)

        1. Mark 85 Silver badge

          Re: @Jake That's going to make one hell of a racket.

          As the saying goes: "In space, no one can you scream."

          1. Mark Exclamation

            Re: @Jake That's going to make one hell of a racket.

            If 3 galaxies collide and no-one hears them, do they actually collide?

            1. Mephistro Silver badge

              Re: @Jake That's going to make one hell of a racket.

              "Do galaxies defecate in the forest?"

              "Is the Pope a galaxy?"

          2. timrowledge

            Re: @Jake That's going to make one hell of a racket.

            Say what? Didn’t hear you.

  2. Pascal Monett Silver badge

    A singularity enters an event horizon

    I can't even begin to fathom how a black hole merger happens inside. The singularity that crosses the event horizon first (I'm guessing the smaller one because smaller event horizon) is attracted to the bigger singularity just like anything else dropping in. What happens then ? Does the singularity start orbiting the other one for a short while ? Does it go straight for collision ? And what is the energy release of such an event forever contained behind the ultimate shroud ?

    Mind-boggling stuff.

    1. sbt Silver badge

      Is that a duck or a peanut?

      I'm thinking they'll resemble contact binaries during the merger. Interesting stuff.

    2. KittenHuffer

      Re: A singularity enters an event horizon

      Internally black holes are (likely to be) rings spinning at close to the speed of light!

      And once you cross the event horizon every direction leads you closer to the singularity inside.

      I don't think the two singularities will orbit each other as that would require them to travel faster than the speed of light.

      I would assume it's one hell of a car crash, and also that our current understanding of physics has no real solution to what happens inside during that collision.

      1. jake Silver badge

        Re: A singularity enters an event horizon

        Ah, yes. Forbes. That great bastion of cutting edge astrophysical thought.

        1. timrowledge

          Re: A singularity enters an event horizon

          The “starts with a bang “ articles are pretty solid, being written by a real physicist that does actual astrophysics etc. By and large even Forbes can’t spin it for politics.

    3. Brewster's Angle Grinder Silver badge

      Re: A singularity enters an event horizon

      I wouldn't think about singularities too literally. They're probably not a real thing. They're just a placeholder in the maths for whatever actually happens inside black holes. We'll get back to you when we've figured that out.

      1. tallenglish

        Re: A singularity enters an event horizon

        Singularity is just a zero viewed from a different angle (at right angle), just as an event horizon is another zero.

        The distance between the two defines all imaginary numbers, so it would take an infinite time to go from one to the other. What is outside the black hole is real spacetime, what is inside a blackhole is imaginary spacetime (at right angles or hyperbolic to us).

        But just as we can point infinitely far from that event horizon to the edge of the universe, we could do the same from the same event horizon to the edge of the imaginary nubered universe on the inside (imaginary from our perspective).

        There is no singularity, just like there is no number infinity that is reachable by traversing along a line of real numbers. It is just a placeholder to define the end, even if its impossible to reach.

        1. Mark 85 Silver badge

          Re: A singularity enters an event horizon

          What is outside the black hole is real spacetime, what is inside a blackhole is imaginary spacetime (at right angles or hyperbolic to us).

          Imaginary probably isn't the right word. "Different" spacetime perhaps, but still real.

          1. jake Silver badge

            Re: A singularity enters an event horizon

            Orthogonal spacetime.

        2. BuckeyeB

          Re: Singularity is just a zero viewed from a different angle

          In the denominator.

    4. BinkyTheHorse
      Thumb Up

      Re: A singularity enters an event horizon

      What transpires beneath the veil of an event horizon? Decent people shouldn't think too much about that.

      -- Academician Prokhor Zakharov

      (from Sid Meier's Alpha Centauri)

  3. Big_Boomer Bronze badge


    "three separate galaxies that ***smashed*** into one another"? Really? Where did you get your journalism badge from? If you had any idea about galactic composition (mostly empty space) then you would have realised that the word "merged" would have been far more appropriate. Anything that takes millions if not billions of years to complete cannot be described as a "smash". Please leave the exaggerations to the tabloids. Otherwise an interesting article.:-)

    1. Alister Silver badge

      Re: Smash???

      El Reg is a tabloid, didn't the red header give it away?

      As a bronze badge holder you should know this.

    2. jake Silver badge

      Re: Smash???

      Well, I dunno about you, but I wouldn't want to get a finger stuck between a couple thingies that have a combined mass several billion times that of our Sun, and moving at a fair percentage of the speed of light. Smashed wouldn't even begin to cover it. Perhaps ElReg actually under-reported the impact.

      Perspective. It's fun to play with.

    3. Rich 11 Silver badge

      Re: Smash???

      By the time they get close enough to each other to merge, they will be travelling* at smashing speed.

      *Were travelling, since they merged a few million years short of a billion years ago.

      1. Michael Wojcik Silver badge

        Re: Smash???

        they merged a few million years short of a billion years ago

        Since causality is also limited to the speed of light, for many purposes it's reasonable to use a timeframe relative to us, and say it's happening now. The absolute timeframe is mostly useful in cosmological questions like the one posed near the end of the article about why we find AGNs in relatively old galaxies.

    4. MiguelC Silver badge

      Re: Smash???

      You do realize that both you and a wall are made up of mostly empty space, don't you? Now try running into (through?) the wall and then tell me if you didn't end up like the icon above...

      1. Jimmy2Cows Silver badge

        Re: Smash???

        Compared to atoms and molecules there's a slight difference of scale, and lack of nucelar forces and chemical bonding between a galaxy's stars. That's why galaxies mostly pass through each other when they merge, whereas you can't run through a wall.

        Gravitational disturbances from the sudden increase in local mass can do some nasty stuff though, and the bigger things are the more they will attract and disturb anything within range.

        1. Jimmy2Cows Silver badge



          Damned insomnia. I meant "nuclear" of course.

          1. Crisp Silver badge

            Re: Oops

            I believe it's pronounced Nucular.

            1. Sleep deprived

              Re: Oops

              Because it involves fusing nuculi?

    5. Big_Boomer Bronze badge

      Re: Smash???

      Alister, fair comment :-)

      Jake, what exactly is travelling at a fair percentage of the speed of light? These are galaxies and black holes. They never even get close to 0.01%C.

      Rich, Black holes may "smash" but they probably don't. Search for info on "The final parsec problem". Galaxies don't smash, even if you massively speed up the merge process.

      MiguelC, Fully aware of that, but they have almost no similarities to each other. Besides, I can and have run through a wall, and still have the scars to prove it. <LOL>

      Jimmy2Cows, ahhh there are edjumakated peepuls on here! :-) The forces at work on galactic scales are gravitational (including Dark Matter).

      It's NEW-CLEAR, not new-kew-lar or nuck-yew-larr, or...... Ok, I'll take my meds now. ;-)

      1. jake Silver badge

        Re: Smash???

        OK, smart guy. Care to place your finger on this anvil? I promise not to hit you with my hammer at a velocity of over 0.001 C ...

        (There's one in every crowd, isn't there.)

      2. Alistair Silver badge

        Re: Smash???

        Lets ask the folks living on some of the planets in those merged galaxies when we get there. I'ma guess that there was some serious smashing going on during that merge. *Mostly* empty space isn't, and large gravitational distortions aren't likely to be too friendly to smaller gravitationally affected objects. Now, timescale, that might be relevant. Sure it isn't much like the scales we're used to, such as when some idiot decides to run a red light on a tuesday afternoon during rush hour, or even that big hole in the middle of the continental america's but I'll bet there were some mighty big extinction events making a lot of noise.

        1. paulc

          Re: Smash???

          I don't think anything can live within a thousand parsecs of these events...

      3. swm Bronze badge

        Re: Smash???

        During the last few seconds of a black hole merger things happen at close to the speed of light. The spins of the merging black holes flip by a large amount and a lot of gravitational energy is emitted. In one case three sun's worth of energy (E = mc2) were emitted and it was brighter than the whole visible universe. The emitted gravitational waves are directional causing the merged black hole to fly off at a large fraction of the speed of light (~ 1/100 C).

        I wouldn't want to be anywhere near such an event.

  4. Ragarath

    There is an easy answer to this...

    “One burning question in astronomy is how these supermassive black holes at the centers of galaxies can grow so quickly, to sizes of one million to several billion times the mass of the sun, because we don’t just see them in close-by galaxies – they’ve actually been detected as early as a few hundred million years after the Big Bang.”

    Sky Fairy - or would that be galactic fairy?

    had to edit to also say, some awesome science!

  5. tallenglish

    I think it is all about the curvature

    There are 3 types of spacetime, AdS (Anti de Sitter, collapsing), Minkowski (flat), and dS (de Sitter, expanding). This is what defines the cosmological constant in general relativity field equations.

    Now we have seen plenty galaxies merge, why not think bigger and also say universes can merge just the same - and thats where the idea of local curvature comes in, what we call the visible universe is just the flat Minzowski plane we can see. We cant see up the hills (dark energy), or down the wells (dark matter) because we use light as our yard stick to measure everything, with the cosmic microwave background defining the edge where it turns up hill (everything flows away from the edge).

    But matter and galaxies could just as easilly drop down the hilly edge of the visible universe (from another universe as it were, or more like a part of dark energh we cant see), just as we can see matter fall into a black hole. So assuming every galaxy is the same age as the visible universe is wrong, yes the visible universe aka the spacetime it is made of is almost flat (very small cosmological constant), but the matter in it doesnt have to be the same age as it.

    What we see is just the valley surrounded by hills, assuming this universe is all there is and ever will be and it came from nothing in a big bang is just stupid small minded thinking at this point. Trying to conbince people the universe is not homoginous is a big task, but when you accept it, black hole size and age, dark matter and dark energy are no mystery at all, they are just matter and energy in different shapes of spacetime to where we are in the flat valley of the visible universe, with erroding hills that give us the expansion in all directions.

    Now I have explained it using valleys, hills and wells, does it sound any different than what we see, even on this planet in nature? Why should the universe as a whole act any differently?

    1. Umbracorn

      Flat Universe Society

      I for one believe the universe is humongous and unhomogenized. More natural that way.

  6. BuckeyeB

    If the universe started from a bang or other similar idea all that matter should be moving away from the central point. If that's the case, how do any galaxies merger as they all should be moving away from each other not toward.

    1. jake Silver badge

      "all that matter should be moving away from the central point."

      It is.

      "how do any galaxies merger as they all should be moving away from each other"

      Local variation is insignificant to the whole.

    2. FozzyBear Silver badge


      It's a bitch.

    3. timrowledge

      I suggest some wider reading on the subject. That isn’t how it works.

  7. Neoc

    When single shines the triple- Oh, wait, never mind.

  8. John Brown (no body) Silver badge

    SDSS J0849+1114 for short

    Shirly for short it should be SDSS J1963

  9. StephenCrothers

    Black holes do not exist.

    Dr. P.-M. Robitaille,

    April 10th, 2019 - Claims of a Black Hole Image: the Day Astrophysics Died,

    Sky Scholar,

    1. jake Silver badge

      Re: Black holes do not exist.

      Methinks that the density displayed in that corner of YouTube suggests that black holes not only can, but must exist.

      This Robitaille crank is the same nutter that claims the source of cosmic background radiation is the Earth's oceans. No, really. Go see for yourself. Or not. Most of us have better things to do than fill our heads with junk science.

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