Follow Slashdot blog updates by subscribing to our blog RSS feed

 



Forgot your password?
typodupeerror
Science

First Measurement of Distribution of Pressure Inside a Proton (phys.org) 174

Okian Warrior shares a report from Phys.Org: Inside every proton in every atom in the universe is a pressure cooker environment that surpasses the atom-crushing heart of a neutron star. That's according to the first measurement of a mechanical property of subatomic particles, the pressure distribution inside the proton, which was carried out by scientists at the Department of Energy's Thomas Jefferson National Accelerator Facility. The nuclear physicists found that the proton's building blocks, the quarks, are subjected to a pressure of 100 decillion Pascal (1035) near the center of a proton, which is about 10 times greater than the pressure in the heart of a neutron star. The result was recently published in the journal Nature.

First Measurement of Distribution of Pressure Inside a Proton

Comments Filter:
  • by MichaelSmith ( 789609 ) on Thursday May 17, 2018 @06:05AM (#56625614) Homepage Journal

    Is Subnuclear fission a possibility?

    • by LordHighExecutioner ( 4245243 ) on Thursday May 17, 2018 @06:11AM (#56625616)
      If there is, it will be taxed.
    • Re: (Score:2, Informative)

      by Anonymous Coward

      I'm not a physicist but theoretically it should be possible. Quarks make up only 1% of the mass of a proton [1], the remaining 99% is the binding energy. If we could harvest that, we could get even more energy per kg of fuel than from nuclear fission.

      [1] https://van.physics.illinois.edu/qa/listing.php?id=30159

      • by Anonymous Coward

        Except quarks cannot exist by themselves.
        So at best you can temporarily MAYBE coax them into quark-antiquark pairs.

        But if you got antiquarks ⦠there is a vastly more energetic process ...

        Maybe if you want to recycle the antiquarks.
        But I don't know if turning 2 trios into 3 pairs would even release any energy ...

        • by Anonymous Coward

          my understanding is that a single quark "cannot exist" mostly because if there was ever a single quark, there's enough energy in the system to make more quarks just pop into existence to keep it company. If they pop into existence, then they can just as easily pop out of existence. So perhaps a process where a proton is split (releasing energy) and the quarks fly off (and almost immediately pair up to their partners out of nothing), or disappear into nothing (perhaps releasing even more energy).

      • by Anonymous Coward on Thursday May 17, 2018 @08:28AM (#56626036)

        Nuclear fission is possible because there can exist free residual nuclei which in sum hold less energy than starting large fissile nucleus. It is a sort of balanced equation of materials and energy, where on both sides of equation you have all materials accounted for, but in terms of energy, you get surplus free energy on resulting side.

        In case of nucleons however, we don't have such equation, because as far as we know, in nature's supply, we only have protons and neutrons, and they are approximately same size. If quarks could exist in free form, or build some stable particles smaller than protons and neutrons, we'd could have a theoretical chance to rob protons or neutrons of a part of their energy.

        • If quarks could exist in free form, or build some stable particles smaller than protons and neutrons, we'd could have a theoretical chance to rob protons or neutrons of a part of their energy.

          Minor pedantry: mesons are made up of only two quarks (technically, a quark and an antiquark), and the lightest mesons, the pions, are lighter than protons and neutrons.

          Pions are only about 15% of the mass of protons, so based on mass, you could get quite a bit of energy out of the conversion of protons and neutrons. The problem is that you would need to convert a quark to an antiquark, which is a bit tricky.

          • by BitterOak ( 537666 ) on Thursday May 17, 2018 @02:56PM (#56628522)

            The problem is that you would need to convert a quark to an antiquark, which is a bit tricky.

            You can't turn quarks into anti-quarks, and this is directly related to the conservation of baryon number [wikipedia.org]. Protons and neutrons have baryon number 1 each, while mesons have baryon number 0, and as far as we can tell, baryon number is a strictly conserved quantity. Since protons and neutrons are the lightest baryons, the "sub-nuclear" fission described is, as far as we know, not possible under the laws of physics as we understand them.

            • Yeah, I was intentionally understating it. C'mon, I wouldn't be on Slashdot if I wasn't sarcastic all the time.

              I guess you could convert a proton (uud) and an antineutron (u'd'd') to three pions, and that would conserve baryon number. Two of those pions might annihilate and give you even more energy. Of course, at that point, you might as well just get your energy from neutron/antineutron or proton/antiproton annihilation and skip the extra steps.
      • Re: (Score:2, Interesting)

        by jellomizer ( 103300 )

        The issue is the power that we use is mostly mechanical energy, which then gets converted to electromagnetic.
        There is significant power loss when ever we change energy (well it isn't lost, it is converted into an unusable form, such as sound, or heat dissipation).
        Even with protonic fission we are still heating up water to create pressure difference to move a turbine that spins magnets which pushes and yanks electrons around.

        We also have chemical energy from batteries and solar cells which more directly crea

        • by Wulf2k ( 4703573 )

          "radioactive waste of nuclear energy,"

          I think you mean "more free energy from nuclear energy".

          All the nasty types of waste are really just great sources of fuel that nobody can tap into because politics won't let them build a reactor design from this century.

        • It sure what this boilerplate post is about, but cheaper, massive amounts of energy, especially non-polluting, is a valuable goal.

          With cheap enough energy, you can cheaply boil ocean water to distill fresh for people around the world.

      • by qeveren ( 318805 )

        The problem there is that in order to take a nibble of that binding energy you have to find a lower energy state for everything to drop into, and there doesn't seem to be one available.

    • Yes, using the not yet developed nuclear proton micropile reactor.
    • by Zorpheus ( 857617 ) on Thursday May 17, 2018 @07:28AM (#56625838)
      Only if quarks could exist in a state of lower energy than inside a proton. I don't think such a state exists, so the answer is no.
      What is possible is matter-antimatter annihilation. So if we found a cheap source of antiprotons ...
    • by pezezin ( 1200013 ) <[se.oohay] [ta] [46nizezep]> on Thursday May 17, 2018 @08:19AM (#56626006)
      Maybe. Some physicists have proposed the existence of "electroweak stars", where energy would be generated from a process know as "electroweak burning" where quarks are converted to leptons: https://en.wikipedia.org/wiki/... [wikipedia.org]
    • by lgw ( 121541 ) on Thursday May 17, 2018 @08:52AM (#56626128) Journal

      Is Subnuclear fission a possibility?

      Well, the proton is already the lowest energy level. The binding energy for hadrons works a bit differently than for atoms - pulling a quark out of a photon requires so much energy that new quarks are created and the quarks remain bound in particles. Free neutrons, OTOH, decay with a half life of ~14 minutes IIRC, when they aren't packed in tightly with other protons and neutrons.

      TFS is a bit odd too. Of course the pressure in a proton is greater than in a neutron star - when the internal pressure in a start exceeds the pressure inside a neutron, the neutrons collapse and you get a black hole. And protons and neutrons are reasonably similar.

      • when the internal pressure in a start exceeds the pressure inside a neutron, the neutrons collapse and you get a black hole

        I thought that the reasoning should be ''when the internal pressure in a star exceeds the pressure inside a neutron then another interesting object will be created which may look like a single superneutron, but before that happens the star will turn into a black hole for different reasons.

        • by lgw ( 121541 )

          You may well be right. [wikipedia.org] However, I suspect a quark star only exists inside a black hole, which would make it hard to verify. (Much like the theory that F6 tornadoes exist, but only inside an F5, so how can you ever prove it?)

          • I regularly notice that black holes are used as some kind of 'structural' mechanism in stars while it's in principle independent of strong forces or the life cycle of a star. Maybe there is a theoretical solution where a huge star becomes a black hole at the start of the lifecycle. From an elementary reasoning the Schwarzschild radius is proportional to mass so a low density cloud which is large enough can already be a black hole.

            In a way the idea of a quark star in a black hole only comes up because we're

    • Is Subnuclear fission a possibility?

      You would have to identify a usable lower energy state that you could 'fission down' to.

    • No and yes.

      Yes, it's possible and indeed 'subnuclear fission' is already done in particle accelerators, you can smash a proton into a quark plasma -- although at those energies you are spontaneously generating new particle/anti-particle pairs so the idea of discrete particle identities makes a bit less sense.

      No, there's no energy to be had there. The proton is stable for at least 10**34 years (age of the universe is 10**10 year) and so any such fission will necessarily require you put in more energy than yo

    • Absolutely. Neutrons can decay to a Proton and Electron and extra energy. This is fission of a nuclear particle which I think is what you mean by Subnuclear fission.
      • Absolutely. Neutrons can decay to a Proton and Electron and extra energy. This is fission of a nuclear particle which I think is what you mean by Subnuclear fission.

        Not really. Fission implies splitting of parts that are already there. Neutrons aren't made of protons and electrons; that was the hypothesis at one point, but observations of particle spin didn't match the predictions you would get with a neutron that contains a proton and an electron. Neutrons become protons and electrons (and antineutrinos) by converting a down quark to an up quark.

        • If I had mod points, I would mod your response up because its thought provoking. It does however have the makings of an interesting debate.

          By definition - Fission: the action of dividing or splitting something into two or more parts. By saying "Fission implies splitting of parts that are already there." you are making an arbitrary decision on the meaning of fission. At best this is semantics and splitting hairs. Please provide a generally accepted reference that shows proof that fission only involves the
    • by kiminator ( 4939943 ) on Thursday May 17, 2018 @02:07PM (#56628258)

      I'm assuming by this term you mean a fission process which occurs within protons or neutrons, rather than within atomic nuclei. The answer to that is no, no matter how you slice it.

      A short explanation for this is simply that quarks are stable particles, like electrons. It's not possible for there to be lower-mass versions of the up/down quarks which we haven't yet observed. There are certainly higher-energy versions of these same particles, but quarks themselves cannot exist except when bound to one another, either in mesons (two quarks) or baryons (three quarks, like protons and neutrons).

      The reason why quarks can't exist alone is that if you take a meson and try to pull apart the two quarks that make it up, it takes so much energy that a quark/anti-quark pair is created, so instead of pulling a meson apart to get two quarks, you end up with two mesons. Similar things happen if you try to pull a quark out of a baryon (like a proton): you end up with a baryon and a meson instead of a meson and a free quark.

      In the end, the proton is the lowest-energy stable state that a collection of three quarks can wind up in (mesons are all unstable, and rapidly decay into either electrons/positrons and neutrinos if they have charge, photons if they do not). But higher-mass baryons, of which there are a great many, will decay into other baryons and collections of particles. This process of more massive baryons decaying into protons/neutrons is probably the closest thing to "subnuclear fission" that exists.

  • by Anonymous Coward

    And where is there a safe space for those poor quarks?

    (Also, BeauHD, you shmuck: It's 10^35, or write 10e35, not 1035).

  • by Anonymous Coward

    In thought strong force refers to the force that binds the protons inside the necleus.... Do quarks even need a force holding them together? Like does opposite spin quarks repel each other?

    • Color force (Score:5, Informative)

      by Okian Warrior ( 537106 ) on Thursday May 17, 2018 @09:08AM (#56626216) Homepage Journal

      In thought strong force refers to the force that binds the protons inside the necleus.... Do quarks even need a force holding them together? Like does opposite spin quarks repel each other?

      The color force holds three quarks together in a proton or neutron. Protons have charge, so there's significant repulsive force among them inside the nucleus.

      A quark inside a proton can be bound (by color) to the two other quarks in that proton, but it's also physically near the quarks of a neighboring proton. It can "look outside" it's own particle and see other nearby quarks, and feel the color force from those as well. That's what we call the strong force, and it keeps the nucleus together.

      If heavy nucleii were composed completely of protons, the aggregate electromagnetic repulsion would overwhelm the strong force and the nucleus would fly apart. Adding a few neutrons to the mix allows the same sort of neighboring-color-attraction without the EM repulsion, and makes the nucleus stable.

  • to quote marty (Score:4, Insightful)

    by sad_ ( 7868 ) on Thursday May 17, 2018 @06:53AM (#56625724) Homepage

    heavy

  • 1035? (Score:5, Informative)

    by johannesg ( 664142 ) on Thursday May 17, 2018 @07:01AM (#56625744)

    1035 doesn't sound so bad. 10^35 on the other hand...

    • by Anonymous Coward

      It’s only missing some zeros....

    • by ari_j ( 90255 )

      1035 doesn't sound so bad. 10^35 on the other hand...

      For years now, the editors have not understood science. Now, they don't even understand scientific notation.

  • by OzPeter ( 195038 ) on Thursday May 17, 2018 @07:01AM (#56625748)

    If you are in the Newport News, VA area on Saturday, the Jefferson Lab is having an open day from 9AM to 3PM. https://www.jlab.org/ [jlab.org]

    Also the press release from the lab itself about the Proton pressure QUARKS FEEL THE PRESSURE IN THE PROTON [jlab.org]

    • As a tidewater native, I'm really exited to see this quality of research coming out of Jefferson Lab. It's a great asset to the area.
      • by OzPeter ( 195038 )

        As a tidewater native, I'm really exited to see this quality of research coming out of Jefferson Lab. It's a great asset to the area.

        If only they could turn their expertise to solving pressure waves on I-64

        • "Pressure wave" traffic jams I assume? That's a solved problem - all that remains is to convince drivers to implement the solution, one that every colony ant on the planet already uses: every driver must try to always remain roughly equidistant between the cars in front of and behind them, which causes the waveform to dissipate.

          Ants don't have traffic jams. Humans on the other hand aren't smart enough to avoid them. Riding that guy's bumper isn't going to save you more than a few seconds, at most, but g

          • by anegg ( 1390659 )

            Hmmm. Rather than having everyone switch over to self-driving cars, perhaps what would work here is to have all cars equipped with a collision avoidance/following distance maintenance system with haptic feedback. The technology for maintaining following distances exists, although it is not usually tied to the accelerator with haptic feedback.

            The idea is that your car's accelerator would behave normally until your car got within a speed-determined distance from the vehicle in front of you. At that point

            • An interesting idea, except you don't want to maintain a fixed following distance - that's what creates the conditions for pressure waves to exist. You want to dynamically adjust following distance based on how much space you have behind you as well. If there's a bunch of empty space behind you - slow down and spread out - then the person in front of you now has more space behind them, and should do the same thing, etc,etc,etc. Likewise, if there's a bunch of empty space in front of you, and traffic behi

  • Macroscopic concept? (Score:5, Interesting)

    by Anonymous Coward on Thursday May 17, 2018 @07:04AM (#56625754)

    Could someone please explain this? I always thought pressure was a more macroscopic concept, related to the force exerted by (many) bouncing particles on a wall, or similar. What is the meaning of pressure within a proton? And what is its meaning? Like density or "edges", I would think macroscopic concepts are no longer valid in that realm.

    • by CustomSolvers2 ( 4118921 ) on Thursday May 17, 2018 @07:26AM (#56625830) Homepage

      pressure was a more macroscopic concept

      Pressure is force per unit of area and is relevant in any context where an area exists. No matter how small quarks are, they are 3D objects and forces applied on them can be modelled via pressure.

      Like density or "edges"

      Same than before: size doesn't matter for any of this. See the proton as an sphere and the elements inside it having certain distribution.

    • You might be right if a proton was merely three quarks. But it turns out that this is not the case: protons are sort of a cloud of quarks, anti-quarks, and gluons. The "three quarks" are known as the valence quarks (they're the only ones that aren't paired with anti-quarks), but only make up a small fraction of the total mass (without looking it up, I think it's something like 5-10%). Nearly all of the rest of the energy is made up a dynamic swarm of particles. The sheer number of particles inside a pro

    • Pressure is force per unit area (as so many have pointed out). In a static(ish) system a force in one direction must be balanced by one opposing it. If youâ(TM)ve got a jar of air, the walls of the jar feel pressure from the air molecules hitting them, and oppose that pressure with forces generated from the electromagnetic force holding the glass molecules together.

      Protons must also experience balanced forces, or they would collapse or explode. The inward force is probably mostly the strong force. The

  • So is it pressure (something pushing them together, like it says) or attraction (something pulling them together)? Or something else completely different because they're quarks?
  • by Anonymous Coward

    "Wow, another day stuck in this darned nucleus, wondering if today will be the day we fall apart, not knowing what element I'll be part of next. Always worrying about whether the electrons out there really care about me or not. And what am I going to do if something takes an electron away from me--I mean us. I'll feel so empty. Yet there's this continuous pressure to perform, to keep it together. Keep hanging on, keep hanging on..."

  • I always knew I was under constant pressure, but this is ridiculous.

  • > which is about 10 times greater than the pressure in the heart of a neutron star

    Superman should upgrade his Fortress of Solitude key to embarrass the Hulk even more.

  • So, it's common for protons to resist pressure greatly higher than that found in a neutron star's core. Doesn't 10x greater than a neutron star's core - how big of a neutron star? - reach into the realm of gravity high enough to trap light? Doesn't this mean that some objects we perceive as black holes aren't singularities on the inside, but that the same force that keeps protons from collapsing into singularities will work for a star? Hence, they'd be quark stars *and* they'd appear like black holes fro

  • Neutron stars are, it turns out, pussies. Every one of my protons says so.

    This begs the question though, what kind of pressure exists within a neutron, and is that pressure higher with the weight of a neutron star sitting on top of it?

    For all the bravado I've just exhibited over the relative pressure inside my protons compared to that within a neutron star, I probably would not want to get into a fight with one though.

Things equal to nothing else are equal to each other.

Working...