Animation of the Higgs mechanism, the process by which particles acquire mass. This occurs when particles interact with an all_pervading Higgs field blue speckles. Some particles do not interact with this field, and are massless and move at the speed of light. When particles do interact, they attract Higgs bosons blue, which are the quanta of the field in the same way that photons are the quanta of the electromagnetic field. Accumulation of Higgs bosons gives mass to the particle, slowing it down. The more bosons are attracted, the heavier the particle and the slower it moves. The Higgs boson is the last undiscovered boson predicted by the Standard Model of particle physics.