PHYSICS The Weight of the World Is Quantum Chromodynamics

(Figure Presented) The busy world of the QCD vacuum. The interior of a hadron, such as the proton or neutron, is not static. Gluons fluctuate in a collective fashion, illustrated by the red-orange-yellow-green-blue fluid. Sometimes the gluon field produces extra quark-antiquark pairs; here, a proton (uud) has fluctuated into a Λ hyperon (uds) and a kaon (s̄u). Animations of these phenomena are available at (7).