The Standard Model and General Relativity
← Theories of Everything · Glossary
Author: Many; SM assembled 1961–1973, GR by Albert Einstein, 1915
Published: Continuously, in the peer-reviewed physics literature
Reference: Standard Model
The two theories that actually work. Between them they describe every experiment ever performed — and they cannot both be right as written, which is the entire reason a theory of everything is wanted.
Standing: Survives experimental test. Mainstream physics.
Why this is the baseline, not a rival
Any theory of everything is a proposal to replace or unify these two. Listing them first is not padding: without them there is no problem to solve.
The Standard Model describes three of the four forces and every known particle, and its predictions have survived tests to a precision of parts per billion — the electron magnetic moment is the most accurately verified prediction in science. General Relativity describes gravity as the curvature of spacetime, and has passed every test from Mercury’s perihelion to the detection of gravitational waves in 2015.
The incompatibility, stated plainly
GR treats spacetime as a smooth continuum. Quantum field theory treats fields as fluctuating at every scale. Apply quantum methods to gravity and the answer diverges — the theory is non-renormalisable, producing infinities that cannot be absorbed.
In ordinary conditions this never matters, because gravity is negligible at particle scales and quantum effects negligible at astronomical ones. It matters at black hole singularities and the first instant of the universe, where both are strong at once and neither theory can speak.
The Standard Model also does not include dark matter, dark energy, or neutrino mass as originally formulated. It is the best-tested theory ever produced and visibly incomplete. Both are true.