The search for simplicity at the deepest levels of nature is one of the enduring themes of physics. Perhaps the greatest milestone in this quest has been the quark model of matter. In the early 1960s, theorists proposed that the scores of known subatomic particles were really composites, made up of just a handful of smaller particles. Even protons and neutrons, the major components of atomic nuclei, could be described as being made of these more fundamental objects, called quarks.
One physicist who laid the intellectual groundwork for this now mainstream theory, Caltech's Murray Gell-Mann, long ago won the Nobel Prize....