It originally treated the four fundamental forces as distinct, but under supremely high energy conditions, such as during the origin of the universe, all the forces should obey the same equation. Nevertheless, the standard model was and is incomplete. See also: Baryon Detection of the Higgs boson Elementary particle Gluons Hadron Higgs boson Higgs boson detection at the LHC Lepton Matter (physics) Quarks Standard model Strong nuclear interactions Weak nuclear interactions

The detection of the long-sought Higgs boson particle in 2012 at the Large Hadron Collider was taken as a powerful confirmation of the standard model. (Electrons, muons, and their like fall into a separate family of particles called leptons.) The four interactions affecting matter are electromagnetism, the weak nuclear force (which governs the radioactive decay of atomic nuclei), the strong nuclear force (which bundles quarks into hadrons and also holds together baryonic hadrons in atomic nuclei), and gravity. In the standard model, the atomic particles classified as hadrons (such as protons, neutrons, and mesons) consist of different combinations of more fundamental particles called quarks. Today, physicists’ most complete theory for explaining nature is the standard model, which has been extremely successful in describing all the known fundamental particles constituting matter. See also: Electromagnetism Gravitation Gravity Physics Quantum mechanics Relativity The quest to unify all these concepts and observations within a single framework will no doubt remain one of the greatest challenges in physics for years to come. The challenge became all the harder with the dual rise of Albert Einstein’s theory of general relativity and the theory of quantum mechanics, both of which have been robustly verified by experiments even though they seem irreconcilable. In the 20th century, physicists continued to discover new primordial particles and forces and labored to unite them as well, with mixed success. In the 19th century, James Clerk Maxwell offered a second great unification by demonstrating that electricity and magnetism were different manifestations of a single underlying electromagnetic force.

Isaac Newton was perhaps the first to succeed in part during the 17th century when he united astronomy and physics by showing that the elliptical orbits of the planets discovered by Johannes Kepler could be fully explained by Newton’s own laws of motion and a universal gravitational force. An ongoing endeavor in physics for at least the past three centuries has been the attempt to unify the disparate phenomena of nature within a single theoretical framework and a single set of descriptive equations.

Fundamental forces unification