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    • In school you learn something along the lines of a proton has a "weight 1 of atomic unit". Well, turns out, if you take the proton parts (quarks and whatnot), the weights just don't add up. That we found out in school because we were nerds already back then.

      New measurements go much beyond that. "Dissecting the mass of the proton" is an entertaining read:

      Nearly all the mass of known matter is contained within protons and neutrons—the particles that make up the nuclei of atoms. But how do the protons and neutrons acquire their mass? Each of these particles, or “nucleons,” is composed of a dense, frothing mess of other particles: quarks, which have mass, and gluons, which do not. Yet the quark masses only add up to a mere 1% of a proton or neutron’s mass, with the bulk of the proton mass coming purely from the motion and confinement of quarks and gluons.

    • Chris MacAskill

      Each of these particles, or “nucleons,” is composed of a dense, frothing mess of other particles: quarks, which have mass, and gluons, which do not.

      Fascinating! That's some pretty deep nerdery. Is there no end to the enormity of the universe or the incredible tinyness of its components? Are we going to discover someday that quarks and gluons are made from dense, frothing messes of even tinier particles? Is this an Elon Musk simulation?

    • Woah. So...can someone smart explain like I'm 5 how "motion and confinement" result in mass?

      In my head I'm envisioning quarks and gluons flying around in a really tight space and bouncing off of each other, but I don't understand how this could result in the creation of mass. I guess I've always thought of mass as a measurement of an amount of stuff, not a measurement of what that stuff is doing.

    • There are some lovely equations called the Lorentz Transformations that explain how, as mass moves at speeds approaching "c", the speed of light, the length of the mass decreases, the time experienced by the mass slows down, and most importantly in the current situation, the mass increases. Much of the mass increase inside protons and neutrons is because the quarks are moving so FAST. Once you accept the Lorentz Transforms, that becomes the easiest of the various mass contributions to grasp, I think. The others are variations on the same theme - that there is this equivalence between energy and mass, thank you Einstein, and inside protons we cannot readily sense or release that energy, but now we can tell that it is giving rise to sensible mass.