19 ms·
Swirling Forces, Crushing Pressures Measured in the Proton
- optimalsolver 3y agoContinuing on this path of scientific enquiry, will we at some point finally understand what this is all about? Why there should be such a thing as a proton, and why it has the properties it does?
- drpossum 3y agoIf you feel like this article is pretty empty in terms of "answers" and "new directions" and the fact that research group has been pushing these ideas for years, again, without any breakthroughs or challenging present understanding, what do you think that means for the quality of the research? This is at best a "ok, neat" result with some science journalism overreaching of how relevant it is for gravity.
- devmor 3y agoDo you think that all science is useless if it does not produce some incredible feat overturning all understanding of the universe?
- drpossum 3y agoNo, but I did come from that field and I'm tired of seeing this exact article every few months
- lostemptations5 3y agoMaybe I'm ignorant, but I follow this stuff abit and it's the first time I see something like it.
- drpossum 3y agoThis was the last one https://news.ycombinator.com/item?id=39163447 https://news.ycombinator.com/item?id=39163447 and a paper from last year https://arxiv.org/abs/2310.11568 https://arxiv.org/abs/2310.11568 and basically the same paper from three years ago (you'll recognize one of the plots from the last article) https://arxiv.org/abs/2104.02031 https://arxiv.org/abs/2104.02031
- lostemptations5 3y agoOk, fair enough
- NoMoreNicksLeft 3y agoI think, in fact, that there might be more than one proton.
- fsmv 3y agoMaybe conceivable with electrons since they're fundamentally simple but protons are made of other things and can be broken while other protons remain so I don't think it's possible there could be only one.
- NoMoreNicksLeft 3y agoImagine living in a universe where someone broke the one proton. Now we have to sit here for eleventy eternities all disincarnate waiting for new laws of physics to congeal. "Honestly, are you never going to let this go? I had goo reason to think there was more than one proton!"
- wredue 3y agoSome things just “are”. There is no “why”. There is a “how”, and we may never be able to answer that question.
- deleted 3y ago[deleted]
- blueprint 3y agoYou shouldn't say there is no why if you simply don't know. You should say I don't know what the why is yet. Otherwise, you might actually believe yourself. I can tell you the why for some of those things that you had no idea had an explanation before. it's like how doctors used to say, there is no cure for X for years and years until at last it turns out that there are multiple treatment pathways.
- drdeca 3y ago> You should say I don't know what the why is yet. I think this seems to make the opposite assumption, which also seems questionable. Rather than “I don’t know the ‘why’ “, I think it would be better to say “I don’t know if there is a ‘why’, nor what it is if there is one.” . Though, really, I think the question of “why” in this context, is a little unclear as to what exactly it is asking? Like, what properties would a statement have to have in order to be a satisfactory answer to the question? Like, if something like color confinement is inevitable assuming SU(3) symmetry, would this answer “why” hadrons exist? Or, if the fact by itself wouldn’t, would this fact, along with a mathematical proof of it, arranged in a way reflecting the core ideas of the proof, constitute a “why hadrons exist”? Or, is the question asking something more, like, “why is there something rather than nothing?” ? Is it asking for the first cause?
- blueprint 3y ago> Rather than “I don’t know the ‘why’ “, I think it would be better to say “I don’t know if there is a ‘why’, nor what it is if there is one.” . Yes, very nice! But I didn't want to go down that rabbithole as you actually need more correction factors... because a person who doesn't know, doesn't know if they know or not. ;) But functionally, they can't say they "know" - they are not conscious - so they don't know if they know or not, and they don't know what knowledge they have may contain a "why" or not, etc., i.e. there is great knowledge in history but people don't realize or have forgotten what resides in their own consciousness or history yet. > Though, really, I think the question of “why” in this context, is a little unclear as to what exactly it is asking? Also very good. 'how' and 'why' converge. That's why a person should make clear what they're asking. Just because 'why' and 'how' converge doesn't mean 'why' is meaningless or useless. In fact, why does something exist is different from how, since any "how" explanation is implicitly about a process of existence, yet a "why" sometimes explains mechanisms that do not "exist" yet cause what exists. That's why understanding this and enunciating it perfectly is a little beyond human eyesight for now. Philosophy exists for a reason and it's not just bullshit some thinkers made up (nor does it culminate with some semi-Wittgensteinian cop-out that words are the best we can do. What a nonsense self-contradiction). Why means many things. People should stop conflating them and ask one by one concretely what they want to know if they truly want to know. But many people can't even realize what their real questions are without some dialogue. Why there is something rather than nothing is that nothing can't exist. One little modern explanation: the moment you put boundary conditions on, you get virtual particles. QFT is clear about that. Without boundary conditions or a metric, there is no way to even consider the notion of a vacuum or nothingness. Answering your question involving SU(3) symmetry requires you understand why/how SU(3) is pre-determined. The place where "why" and "how" diverges is when involving a subject: "why am I alive" vs "how am I alive". The second one is a lot easier to answer if you consider only the biological. If you don't understand what the point of life is, it will be a lot harder to understand your distant past and a lot harder to understand your ultimate "why" i.e. your path and your purpose in this life. Consider what you know, for starters: you are like a child in this universe, growing up and learning through your life. When someone has to learn and grow, it means they're on the path to realization, mastery, and complete knowledge. I'll leave it at that for now.
- innagadadavida 3y agoHad there been any scientific studies into why the elements are perfect and there are are all apparent to perfect replicas with not defect rates? It’s hard to make perfect replicas at scales higher than the atomic scale but at the lowest levels, everything seems to be identical.
- cjameskeller 3y agoCouldn't one say that different isotopes of elements are exactly such "imperfect" replicas?
- dexwiz 3y agoIsotopes and elements are human made labels based on nucleon and proton counts. Hydrogen and deuterium are both the same element, but are obviously different nuclear structures. Even at a chemical level deuterium is appreciably different. That difference between isotopes and elements diminishes but never disappears as atomic mass rises. Isotopes are only imperfect in the context of one labeling system. But not from a quantum viewpoint.
- mr_toad 3y agoThe isotopes are examples of why atoms are not really atomic at all. Once something that you thought was atomic actually shows variation you begin to suspect it is composed of smaller things.
- jmole 3y agoI'm not a physicist, but isn't this 'everything is identical' model fundamentally incompatible with quantum mechanics? There seems to be hidden quantum state encoded within the proton and other subatomic particles, although that state may not be relevant to the interactions that we care about on a day to day basis. Your comment does remind me of this though: https://en.wikipedia.org/wiki/One-electron_universe https://en.wikipedia.org/wiki/One-electron_universe If we are not in a one-electron universe, every electron is unique in the sense that it has an entirely unique path though spacetime, and thus can't be identical. I think what you mean is that every one of these "particles" seems to obey the same set of laws, which is not something that's unique to atoms, subatomic particles, or even larger things like molecules.
- vundercind 3y agoScience doesn’t really answer “why”. It’s better at “how”.
- postalrat 3y agoI'd say science can't answer "how" but can answer "when".
- joquarky 3y agoI find Alan Watts to be informative in pondering these kind of questions, as "why" isn't really in the realm of science.
- bmacho 3y agoProbably we will at some point. It is possible that it will turn out that our whole world is, say an ever growing finite system with a simple rule. Say someone identifies some laws ruling the digits of pi, that's a physics, then they look more, and they observe that the CMWB pattern on the sky is in the pi too, and voila, we live in pi confirmed (or at least it would make it very plausible). Then protons exist, and protons are the way they are, because some properties of the circle.
- notamy 3y agoThe methods scientists come up with to test things like this are absolutely incredible, wow.
- rkowalick 3y agoI remember being blown away when I was told about Henry Cavendish’s attempt to calculate G (the gravitational constant) in the late 18th century: https://en.wikipedia.org/wiki/Cavendish_experiment https://en.wikipedia.org/wiki/Cavendish_experiment
- hkwerf 3y ago"Attempt" may be an understatement, as it worked. We hat this experiment set up in one of our lecture halls once a year. They had to fence off the area and it had to relax for days, but we were able to replicate the measurement during our introduction to physics lecture. There was also a lab course on a smaller version. (Video of it, in German though: https://m.youtube.com/watch?v=8W8X71wW8F0 https://m.youtube.com/watch?v=8W8X71wW8F0)
- AnimalMuppet 3y agoI ran the experiment in an undergrad physics lab. When we ran it, we had to disable the elevator down the hall for vibration reasons.
- abecedarius 3y agoSame guy who discovered, among other things, > the concept of electric potential (which he called the "degree of electrification"), an early unit of capacitance (that of a sphere one inch in diameter), the formula for the capacitance of a plate capacitor, the concept of the dielectric constant of a material, the relationship between electric potential and current (now called Ohm's law) (1781), laws for the division of current in parallel circuits (now attributed to Charles Wheatstone), and the inverse square law of variation of electric force with distance, now called Coulomb's law. (Wikipedia) Wonder what went wrong to need so many rediscoveries by others. Reminds me of Gauss.
- ecommerceguy 3y agoAs humanity continues to peel back the layers of reality, I sure feel more and more like maybe this indeed is a simulation.
- deleted 3y ago[deleted]
- morkalork 3y agoHere, see this and relax: https://i.imgur.com/x2BzFRB.jpeg https://i.imgur.com/x2BzFRB.jpeg
- drdeca 3y agoAll of those before the simulation, seem like fairly useful metaphors, that describe something real about the world. Indeed, there are many things about the world that go in cycles. Indeed, much of how the world behaves can be seen as acting according to exact, “mechanical”, rules (like, the laws of physics), etc. .
- ThrowawayR2 3y agoOn the bright side, finding out that we are all in a simulation would at least provide the answer to the perennial question about the meaning of life, dohohoho.
- fsmv 3y agoHow can it make sense to measure the stress-energy tensor of a proton given that we have no theory of quantum gravity? Are they somehow ignoring quantum mechanics?
- vlovich123 3y agoThis is preliminary work. The bigger issue is that this is happening at energy scales that ignore things like gluons. > Sharper gravitational maps of both the proton’s quarks and its gluons may come in the 2030s when the Electron-Ion Collider, an experiment currently under construction at Brookhaven, will begin operations. It would be hard to imagine the scientists are ignoring quantum effects since light + proton screams quantum, so it's unclear from the reporting alone if the lack of a quantum gravity theory is enough to make all this not particularly useful or if this is just bad reporting and the experts are confident this is the right way to do things "for reasons". My guess it's probably a mixture because the modelled answer computed from equations and the measured result seem to be aligned.
- avpix 3y agoThey are measuring the distribution of energy within the proton. General relativity (GR) describes how a distribution of energy distorts spacetime. They could take these measurements of the proton (if they're complete enough) and compute its tiny effect on the curvature of spacetime with non-quantum GR. Quantum gravity only becomes relevant at the Plank length (~10^-35m) which is still much smaller than the proton radius (~10^-15m) or the resolution of their measurements.
- misja111 3y ago> .. a graviton, the hypothesized particle that conveys the force of gravity I thought it was the Higgs boson that was doing this? But obviously I misunderstood something. Could anybody explain what's the difference between those particles?
- Firaxus 3y agoI believe the Higgs boson is what generally gives particles mass, which is different from particles which create fields and forces?
- AnimalMuppet 3y agoThe Higgs boson (or maybe the Higgs field?) gives mass to everything else. The graviton creates the attractions between masses.
- zdragnar 3y agoHiggs boson conveys mass. Mass is not necessary for a gravity field. Massless particles such as photons can convey both gravity fields and momentum. In short, gravity is correlated with energy density, which coincides with mass (via e=mc2) but the mass itself is not directly responsible for the gravity field, per se.
- ginkgotree 3y agoI'm "positive" this will be a great read.
- perihelions 3y agoI'm glued-on to my computer screen!
- phkahler 3y agoThey show the forces tangential to the surface of the proton, going around one way near the "surface" and the other way in the middle. However, the hairy ball theorem says there must be something like "poles" in this case. https://en.wikipedia.org/wiki/Hairy_ball_theorem https://en.wikipedia.org/wiki/Hairy_ball_theorem I'm wondering if their proton map covers that, and if the "axis" corresponds to anything familiar.
- jeffwass 3y agoBelow quote from your wiki link. I’m not a graphics guy, but would appreciate if someone with experience in computer graphics could please give an example of this common problem. “A common problem in computer graphics is to generate a non-zero vector in R3 that is orthogonal to a given non-zero vector. There is no single continuous function that can do this for all non-zero vector inputs.”
- arbitrandomuser 3y agoi might be misunderstanding , but it seems easy if you want a vector orthogonal to A , generate a random vector B non co-linear to A and take AxB (cross product). AxB is orthogonal to A .
- perihelions 3y agoRight: and that's not a single, continuous function that works for all inputs—specifically, it fails on the input B itself. BxB = 0. Any solution will have a discontinuity in its output vector angles. I don't know how this problem is applied in computer graphics, but you probably want to avoid rendering objects in the vicinity of a discontinuity: you'd get some kind of flickering artifact when you cross it, with small ɛ-displacements being amplified into something much larger.
- itishappy 3y agoThis does not work on all non-zero vectors, hence your "non co-linear" comment. If the vectors point in the same direction, the cross product is zero, and you have an extra degree of freedom when choosing your "up" vector.
- api 3y agoIs there a relationship between the intense forces here that are apparently balanced and stable and the fact that mass is equivalent to insane amounts of energy (via E=mc^2)? Is mass basically a ball of balanced forces ready to explode if this balance is disrupted? If so then it seems interesting that this tension's potential energy maps exactly to mc^2.
- itishappy 3y agoI think what you're describing is called the stress-energy tensor, which as I understand it is a generalization of mass. https://en.wikipedia.org/wiki/Stress%E2%80%93energy_tensor https://en.wikipedia.org/wiki/Stress%E2%80%93energy_tensor
- mrkstu 3y agoSince matter is basically precipitated energy from the near infinite energies released by the Big Bang, makes sense to me that it has fairly high amounts of energy compacted. If nothing else, nuclear bombs made this blindingly obvious.
- pitherpather 3y agoIt is true in general that the "binding energy" of a nucleus is reflected in the measured mass or atomic weight, exactly as mc^2.
- dustingetz 3y ago> They found that in the heart of the proton, the strong force generates pressures of unimaginable intensity — 100 billion trillion trillion pascals, or about 10 times the pressure at the heart of a neutron star. Farther out from the center, the pressure falls and eventually turns inward, as it must for the proton not to blow itself apart. This is inside each of us, 100 billion billion billion times
- deleted 3y ago[deleted]
- kazinator 3y ago> “It’s a tour de force,” said Cédric Lorcé I see what he did there.
- froza 3y agoI always wonder, how exactly are gravitons or gluons supposed to create the attraction between two particles? They carry a negative momentum or its just magic? Does it mean that the gravitational force is fluctuating with some statistical distribution of gravitons?
- antognini 3y agoThinking of a virtual graviton or photon or gluon as a particle is somewhat misleading. It is better to think of it as an excitation of the underlying field. It is possible to show (with fairly elementary techniques) that when the excitations have a spin of 2, these excitations always reduce the energy of the system, and so produce an attractive force. If the excitations have a spin of 1, then they increase the energy of the system and so produce a repulsive force. This is why the gravitational force attracts and like charges repel each other.
- AnimalMuppet 3y ago> If the excitations have a spin of 1, then they increase the energy of the system and so produce a repulsive force. This is why the gravitational force attracts and like charges repel each other. But then why do unlike charges attract? The force mediator is still a spin-1 particle...
- antognini 3y agoThe charge is in essence a measure of how strongly the particle couples to the field. If the charges are opposite then the coupling gets reversed and so the excitation reduces the energy. Likewise if a particle somehow had a negative mass, it would gravitationally repel particles of positive mass.
- mr_toad 3y agoThey’re virtual particles, and can get away with having negative energy. They don’t always obey mass energy equivalence either, naughty things. https://en.wikipedia.org/wiki/On_shell_and_off_shell https://en.wikipedia.org/wiki/On_shell_and_off_shell