Gluons

Gluons are particles that carry the strong nuclear force, the strongest of the four forces of nature. They hold quarks together. Quarks form, among other things, protons and neutrons, the building blocks of atomic nuclei. The name comes from the English word 'glue'.

How does it work?

Quarks have a property called colour charge. It has nothing to do with real colours; it is just a name for a kind of charge. Quarks constantly exchange gluons, and that is how they attract each other. You can picture it as two skaters throwing a ball back and forth and thereby staying tied to each other.

Gluons carry colour charge themselves. As a result, they also interact with each other. That makes the strong nuclear force different from, say, electricity, and hard to calculate. The theory that describes this, quantum chromodynamics, is known as QCD for short.

Why it matters

Most of the mass of a proton comes from the energy of the gluons and quarks inside it. So anyone who understands gluons understands where ordinary matter gets its weight.

OpenAI said that its internal AI models have solved three long-open problems in mathematics, computer science and physics. One of them is a mathematical proof about the theories of the smallest particles, including QCD and the Yang-Mills theory that describes how gluons interact with each other (link). That is part of a famous mathematical Millennium Problem. This is a claim by OpenAI itself: independent physicists led by Nobel laureate David Gross are going to check the proof.