back to article Forget Iran and North Korea. Now there's another uranium source

Astronomers have proposed that heavy elements in the universe may have been forged when small, primordial black holes swallowed neutron stars. Boffins widely believe that elements lighter than iron are formed during nuclear fusion reactions in the cores of stars, or during supernova bursts. But to create elements heavier than …

  1. Conundrum1885

    Intriguing

    Certainly fits the data, though the catch is no black holes smaller than maybe 3.8M0 have been seen.

    Yet.

    Would the hypothesis work with micro-black holes as you might see at an advanced state of decay ie maybe a Jupiter's mass or less?

    1. Anonymous Coward
      Anonymous Coward

      Re: Intriguing

      No idea. But I'm still wondering why things like the jets at top and bottom of such supermassive black holes are not also part of some process.

    2. Anonymous Coward
      Anonymous Coward

      Re: Intriguing

      How would we observe a small black hole? Its gravity would be too small to observe it by its gravitational effect on surrounding matter, and evidence of material spinning up around it wouldn't help differentiate its size, only the amount of material around it.

      1. bombastic bob Silver badge
        Boffin

        maybe regular stars as well

        just thinking, maybe regular stars also have heavy elements inside the core, due to the compression and continuous neutron flux from the fusion reaction... yeah fusing iron + other things into gold, lead, and uranium would be the nuclear equivalent of 'endothermic' but you got all that pressure, all that temperature, and all those neutrons...

        but yeah Iron, cobalt, and nickel have the lowest binding energy per nucleon, so all 'exothermic' fission/fusion reactions head towards them.

        1. KX1B

          Re: maybe regular stars as well

          Lead is the stable final decayed state of Uranium.

    3. Cuddles

      Re: Intriguing

      "the catch is no black holes smaller than maybe 3.8M0 have been seen."

      Maybe they all collided with black holes already?

      On a more serious note, my main issue with the hypothesis here is that we don't seem to have actually observed anything to support it. It's proposed that there should be an entire new class of supernovae common enough to be a major contributor to the elemental composition of the universe, but we've never seen a single one. Sure, they say it might explain a variety of as-yet unexplained observations, but that's all highly speculative and can't really be counted as supporting evidence at this point. So it's an interesting idea, but so far we're both missing evidence of the actual explosions as well as evidence for one of the two things needed to cause them.

  2. Stratman

    Centrifugal force?

    Whenever I read about centrifugal force throwing stuff outwards, I find myself wondering if the person in question knows as much as they claim.

    In this particular case, 'centrifugal force' would imply a black hole pushing matter outwards away from itself.

    1. Flocke Kroes Silver badge

      Re: Newton's third law

      Whenever I read about someone complaining about centrifugal force, I find myself wondering if the person in question knows as much as they claim.

      Imagine holding a piece of string with a rock glued to the other end. The Earth's gravity pulls the rock down. The rocks gravity pulls the Earth up. The rock pulls down on the string and the string pulls up on the rock. The string pulls down on your hand and your hand pulls up on the string.

      Spin the rock round in circles - you are providing a centripetal force that curves the rock's motion into a circle. The rock provides a centrifugal force pulling on your hand.

      In the article, the spin of a neutron star increases because matter moves into a black hole in the middle. Gravity provides the centripetal force required to curve the motion of the outside of the neutron star into a circle. While the star holds together, there must be an equal an opposite force preventing collapse. That is centrifugal force provided by the spin. The spin increases until centrifugal force exceeds gravity, at which point the star breaks up.

      Centrifugal force is an example of an inertial force (a force proportional to mass). From another (Einstein's) point of view, inertial forces are artifacts created by selecting an accelerating reference frame. Astronauts in a rocket with the engines on experience a force like gravity because they are in an accelerating reference frame. A motor cyclist riding inside a wall of death experiences a force like gravity because he is in an accelerating (rotating) reference frame. People on Earth think that they experience gravity, but gravity is an inertial force. Although you think you are sitting still in your arm chair, you are really in an accelerating reference frame. Centrifugal force is an inertial force that results from selecting an accelerating reference frame and is just as real/unreal as gravity.

      1. Chris G

        Re: Newton's third law

        Just to clarify Stratman.

        FlockKroes said ( Better than I could have) "The spin increases until centrifugal force exceeds gravity, at which point the star breaks up." The spin increases because the black hole is eating the star fromthe inside the radius is becoming smaller, just as when an ice skater pulls in their arms in a spin it becomes faster so does the spin of the statr as it's radius shrinks, if the centifugal force is greater than the gravity of the remaining star material and/or the black hole, material will be ejected.

      2. Anonymous Coward
        Anonymous Coward

        Re: Newton's third law

        "Whenever I read about someone complaining about centrifugal force, I find myself wondering if the person in question knows as much as they claim."

        So you're saying that when, at my interview for Durham all those years ago, I started to answer a question using the words "centrifugal force" I was humiliated so badly I can still remember it, the interviewer who subsequently became a rather important physicist was wrong?

        Ah well, they offered me a place but I went to Fen Poly instead so as not to be reminded of my embarrassment. And now you tell me my interviewer was wrong. Well, one of you is. And my money's on you.

        1. Pompous Git Silver badge

          Re: Newton's third law

          "And now you tell me my interviewer was wrong. Well, one of you is. And my money's on you."
          You can describe the universe with forces (Newton) or you can describe the universe as curved space (Einstein). It's not a matter of either one being "wrong"; they are incommensurable descriptions and both are useful. Feynman's 12th Lecture:

          Characteristics of Force

          1. Chris Coles

            Re: Newton's third law

            "You can describe the universe with forces (Newton) or you can describe the universe as curved space (Einstein). It's not a matter of either one being "wrong"; they are incommensurable descriptions and both are useful. Feynman's 12th Lecture:

            Characteristics of Force "

            To stay within the remits of the rules for discussion here, I have to do my best to strip this debate down to a very basic level. Ergo, to start, these are the two quotations I will use from the Feynman lecture:

            “To push the molecules only slightly closer together requires a great force, because the molecular repulsion rapidly becomes very great at distances less than d. If the molecules are pulled slightly apart there is a slight attraction, which increases as the separation increases. If they are pulled sufficiently hard, they will separate permanently—the bond is broken.”

            “This particular illustration does not describe correctly the way in which Einstein’s geometry is “weird,” but it illustrates that if we distort the geometry sufficiently it is possible that all gravitation is related in some way to pseudo forces; that is the general idea of the Einsteinian theory of gravitation.”

            In the first quotation; “the bond is broken” In the second; “ but it illustrates that if we distort the geometry sufficiently it is possible that all gravitation is related in some way to pseudo forces”.

            But gravity between all the mass remains in place at all times. If that is so, then it becomes impossible for the bond, (gravity), between molecules to be broken. It is this simple anomaly that has become the bane of science ever since it was created. Einstein could not define the origin of gravity, as Feynman himself admits; “the origin of these forces remains obscure.” So Einstein created a solution involving pseudo forces, the distortion of Space Time.

            Thus this has been a debate in front of everyone since Einstein, including Feynman, to provide a solution to the true origin of the force of gravity; the bond that is NOT broken.

            Gravity is caused by the positive electromagnet force field of each proton extending beyond the orbit of that proton’s electron, to attach to the closest adjacent proton’s electron. The “bond” is never broken and as such, conforms fully to the laws of electromagnetism as laid down by James Clerk Maxwell.

        2. Flocke Kroes Silver badge

          Re: Newton's third law

          A great deal would depend on the question, for example:

          Durham interviewer: "Why does heat transfer across a temperature gradient?"

          Anonymous Coward: "Centrifugal force!"

      3. Anonymous Coward
        Anonymous Coward

        Re: Newton's third law

        Just to add that there may be another factor in the breakup of a neutron star after it has 'swallowed' a small black hole.

        The jets produced by the energy and density levels of the matter within an accretion disk around a BH should also effectively occur if a micro/mini BH is swallowed by another body and starts eroding it from the inside. This should result in a considerable out-pressure that, for a short time, balances the gravitational in-fall pressure and supports the outer layers of the neutron star against collapse, pretty much in the same way that the fusion process at the center a star prevents its own collapse.

        I suspect it'll be during this short period of time, when the out-pressure from the BH at its center combines with the centripetal force from its increasing rate of rotation, that the neutron star is most likely to break up.

    2. Francis Boyle Silver badge

      Someone hasn't been reading

      XKCD.*

      *123 if you're interested. It too late here to write HTML and I'm off to bed.

      1. Ken Hagan Gold badge

        Re: Someone hasn't been reading

        It's mid-afternoon here, so here's the link.

        If I may venture an opinion, the further you go in physics the more you start to think that pretty much every "force" is a fictitious one, introduced to explain why particles following "straight line" paths in a coordinate system that respects extremal-action appear to be following curved paths in the 3D sub-space that we are blinkered enough to consider more fundamental.

        Certainly once you've seen magnetism emerge as an illusion of moving frames of reference and gravity emerge as an illusion of curved space-time, the legitimacy of a centrifugal force that emerges in a rotating frame seems fair.

    3. Destroy All Monsters Silver badge
      Windows

      Re: Centrifugal force?

      Phew lad! This discussion is as old as Internet "I am even geeker than you ultrageeks" contests and still being pursued by high scoolers everywhere.

      Learn2GalileanVsRotatingReferenceFrames

      1. Anonymous Coward
        Anonymous Coward

        Re: Centrifugal force? - Phew lad! This discussion is as old as Internet

        But in classical mechanics it is extremely simple. There is no need to invoke complicated frames of reference. All we need to do is to consider things from the point of view of an outside observer.

        It is clear that there is a force between the centres of mass. Applying Newton's laws, we can see that if there were not then they would continue in straight lines in the directions they had when the force was removed. Therefore the force which constrains them is attractive and between them, and is directed towards the centre of mass (for both objects). It is therefore centripetal. This makes no assumption about the relative masses of the objects.

        If the centripetal force were somehow instantaneously to disappear both objects would continue to move at constant velocity. They therefore do not accelerate so there is no force on them.

        A centrifuge works because the centripetal force operates on the pipette but not the particles in the liquid. They therefore tend to travel in straight lines which, owing to the rotation of the pipette, eventually causes them to reach the bottom, or as close as buoyancy permits. There is no centrifugal (i.e. outward) force to be found anywhere.

        1. Flocke Kroes Silver badge

          Re: Voyna i Mor

          "There is no centrifugal (i.e. outward) force to be found anywhere."

          When the giant hamster wheel spins what is the direction that Mr Bond's body/corpse applies to the wheel?

          1. Pompous Git Silver badge

            Re: Voyna i Mor

            "When the giant hamster wheel spins what is the direction that Mr Bond's body/corpse applies to the wheel?"
            Assuming the giant hamster wheel is rotating at a constant rate:

            At any one instant of time, Mr Bond is travelling in a straight line tangent to the wheel. Take away the wheel and Mr Bond will continue travelling in a straight line at constant speed away from where the wheel was.

            The wheel constantly applies a force to Mr Bond to prevent him flying away from the axle. That force therefore must be in the direction of the axle (centripetal).

            Edit: Think of a satellite travelling around the Earth at a constant height. The force doing that is gravity making the satellite fall to Earth while it travels at constant speed.

    4. bombastic bob Silver badge
      Devil

      Re: Centrifugal force?

      spins like a top, stuff flies off. spins faster as it shrinks (momentum conservation). something like that, anyway. A particle would have to be lucky enough to be near the equator

  3. James 51
    Alien

    Any reports of the common cold we can use to track them down?

    Paging Captin Archer.

  4. Nolveys
    Headmaster

    900 times the mass of the Great Pyramid of Giza

    Can someone convert this nonsense to something sensible like units of libraries of congress or football fields covered in elephants?

    1. Alex McDonald 1

      Size of Wales

      Obviously.

  5. Chris G

    @Nolveys

    One teaspoon of Neutron Star surface matter = In mass 900 times The Great Pyramid of Giza = 535714285714.2858Kilojubs

    Or a rounder number would be 1500000000000.0002 Skateboarding Rhinocerii to fit them into a teaspoon you would have to make the wheels on their skateboards reeeaaalllly small.

  6. TheElder

    How would we observe a small black hole?

    When it evaporates.

    That final second of a black hole's life, however, will result in a very specific and very large release of energy. When the mass drops down to 228 metric tonnes, that's the signal that exactly one second remains. The event horizon size at the time will be 340 yoctometers, or 3.4 × 10^-22 meters: the size of one wavelength of a photon with an energy greater than any particle the LHC has ever produced. But in that final second, a total of 2.05 × 10^22 Joules of energy, the equivalent of five million megatons of TNT, will be released.

    What Happens When A Black Hole's Singularity Evaporates?

    1. Draco
      Mushroom

      Re: How would we observe a small black hole?

      The article was a fascinating read and now makes Roger Penrose's notion of a cyclic conformal cosmology seem more probable: we are at the end of the universe, the last moments, nothing remains except for the last evaporating black hole, which goes out in a huge, brilliant outrush of radiation and a new universe begins.

      Icon choice: closest thing to a big bang.

  7. Destroy All Monsters Silver badge
    Windows

    Intriguing

    Unfortunately, there has been no confirmed observation of primordial black hole boiloff via Hawking Radiation so far. Do they exist?

    There was this article on Gold Production in Quanta Magazine recently: A New Blast May Have Forged Cosmic Gold, but it was about Supernova vs. Neutron Star merger only.

    Also:

    The gravitational interaction between the pair causes the black hole to devour the neutron star inside out.

    I would say the Black Hole is rapidly decelerating in the Neutron Star then settles in its middle while having an amazing full-fat meal with a side dish of transfat fries.

    1. bombastic bob Silver badge
      Devil

      Re: Intriguing

      "the Black Hole is rapidly decelerating in the Neutron Star then settles in its middle while having an amazing full-fat meal with a side dish of transfat fries."

      kinda like these...

      https://www.youtube.com/watch?v=vMG-LWyNcAs

  8. TheElder

    Do they exist?

    Perhaps it isn't exactly evaporation but it may well look the same. Quasars?

    Or maybe this:

    White holes

  9. Captain DaFt

    Arm chair musing

    Are small black holes really needed for this?

    The assumption is that the Neutron star collapses uniformly, but is that the case?

    Maybe the core collapses faster than the outer layers can accelerate, causing a rebound shockwave similar to a super nova, but much, much more powerful, blasting the outer layers with enough force to create the heavier elements and disperse them through space?

    Or maybe I shouldn't think about things like this whilst not sober?

    1. TheElder

      Re: Arm chair musing

      The supernova explosion is the sudden bounce caused by fusion at the much higher temperatures caused by insane depression compression. The neutron star is just neutrons and is not able to fuse anything by itself. It is the very final step before a black hole. Some must be right on the edge so just a bit more matter really matters. It falls into a black hole. But everything takes time even if it is nanoseconds.

      The energies and spin rates are incomprehensible. The entire concept of a black hole is something we do not fully understand. What is inside a black hole? Nobody really knows. It must be something to do with matter. The idea of a singularity is just speculation. It makes sense but cannot be proven.

      The old idea was that Black Holes Have No Hair. Just mass, angular momentum and electric charge. However, if evaporation really does exist then there is a great deal of hair happening when the Hole is getting tiny. The hair can entirely cover the hole.... Hmmmm.

      1. Daggerchild Silver badge

        Re: Arm chair musing

        I was wondering if the mini-black was needed too, but my musing was whether the neutron star would hold together if the star whipped past another one, or swung close enough to a conventional black hole, to momentarily mess up the spherical crush and make it spooge its guts out.

  10. G2
    Mushroom

    sooo...

    tl;dr version: they are, quite literally, a cosmic fart from a black hole.

    (chose an icon to match)

  11. BebopWeBop

    or 900 times the mass of the Great Pyramid of Giza

    as an aside - is this an extension of el Reg standards?

    1. TheElder

      extension of el Reg standards

      Reasonable idea. If Giza Pyramids were stacked 900 times it would be a stack 125,100 metres tall. Outer space officially starts at 100 KM. We would have a Giza Space elevator. That would then give us a Giza Ultra Massive Pile Of Real Numbers .

      The acronym would then be GUMPORN...

  12. Anonymous Coward
    Anonymous Coward

    Slapping sanctions on black holes?

    I thought that we as a planet were done with the horrible restrictions on interracial relationships.

  13. Anonymous Coward
    Anonymous Coward

    New physics

    I did wonder if collisions with micro black holes might account for the larger solar flares

    A few small ones in our solar system might not be seen if they were in a very long period eccentric orbit and there is experimental data to back this in the form of unexplained coincidental seismic events as you might see if a BH passed through the Earth at a shallow angle wrt the core.

  14. truetalk
    Stop

    Boffins, I hate that word... Am I reading the Sun or what?

    1. Afernie
      Meh

      No but you are reading a tabloid - the red top is the clue. If you don't like it there are other, much stuffier IT news sites to choose from.

  15. MT Field
    Mushroom

    Physics war lolz.

    But seriously chaps, how do we explain the lumpiness? Hmm? By what process do the heavy elements end up in great rocky lumps, instead of being dispersed as a nearly homogenous mix of heavy atoms?

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