History of Physics Timeline

Albert Michelson and Edward Morley attempted to detect Earth's motion through the luminiferous ether using an interferometer, obtaining a null result. This puzzling failure set the stage for Einstein's special relativity and the abandonment of the ether.

Image source: Michelson–Morley experiment

Wilhelm Röntgen discovered X-rays while experimenting with cathode rays, producing images of bones inside the human body. He received the first Nobel Prize in Physics in 1901, and X-rays revolutionized medicine and opened the door to nuclear physics.

Image source: X-ray

Henri Becquerel discovered that uranium salts spontaneously emit penetrating radiation without external excitation. This discovery of radioactivity revealed that atoms have internal structure and initiated the study of nuclear phenomena.

Image source: Henri Becquerel

J.J. Thomson showed that cathode rays are streams of negatively charged particles much lighter than atoms, discovering the electron. This was the first identified subatomic particle and proved that atoms are divisible.

Image source: J. J. Thomson

Marie and Pierre Curie isolated the radioactive elements polonium and radium from pitchblende. Marie Curie's pioneering research on radioactivity earned her two Nobel Prizes and established radiochemistry as a field.

Image source: Marie Curie

In his annus mirabilis, Albert Einstein published papers on the photoelectric effect, Brownian motion, and special relativity, abolishing the ether and showing that space and time are relative while the speed of light is constant. He also derived E=mc².

Image source: Special relativity

Robert Millikan's oil drop experiment precisely measured the elementary electric charge, confirming the quantization of charge and providing strong evidence for the existence of electrons. He won the Nobel Prize in Physics in 1923.

Image source: Oil drop experiment

Ernest Rutherford's gold foil scattering experiments, conducted with Geiger and Marsden, revealed that atoms contain a tiny, dense, positively charged nucleus. This overturned Thomson's plum pudding model and defined the structure of the atom.

Image source: Rutherford scattering experiments

Einstein completed general relativity, describing gravity not as a force but as the curvature of spacetime caused by mass and energy. The theory explained Mercury's perihelion precession and predicted light bending, black holes, and gravitational waves.

Image source: General relativity

Arthur Eddington's expedition photographed stars near the eclipsed Sun and confirmed that starlight was deflected by the Sun's gravity as general relativity predicted. The result made Einstein world-famous overnight.

Image source: Eddington experiment

Max Planck resolved the blackbody radiation problem by proposing that energy is emitted in discrete quanta proportional to frequency, introducing Planck's constant h. This date is often considered the birth of quantum theory.

Image source: Max Planck

Niels Bohr proposed a quantum model of the hydrogen atom in which electrons occupy discrete orbits and emit or absorb photons when transitioning between them. The model successfully explained hydrogen's spectral lines and advanced old quantum theory.

Image source: Bohr model

Otto Stern and Walther Gerlach passed silver atoms through a non-uniform magnetic field and observed discrete deflections, demonstrating the quantization of angular momentum. The experiment later became crucial evidence for electron spin.

Image source: Stern–Gerlach experiment

Louis de Broglie hypothesized that particles such as electrons have wave properties with wavelength inversely proportional to momentum, extending wave-particle duality to matter. His hypothesis was soon confirmed by electron diffraction experiments.

Image source: Matter wave

Werner Heisenberg developed matrix mechanics, the first complete formulation of quantum mechanics, representing observables as matrices whose products do not commute. This work marked the beginning of fully consistent quantum theory.

Erwin Schrödinger formulated the Schrödinger equation, describing quantum systems with wavefunctions evolving deterministically. Wave mechanics proved mathematically equivalent to matrix mechanics and became the standard formalism of quantum theory.

Image source: Schrödinger equation

Werner Heisenberg articulated the uncertainty principle, showing that position and momentum cannot both be measured with arbitrary precision simultaneously. This fundamental limit reshaped philosophical understanding of measurement and causality in physics.

Image source: Uncertainty principle

Paul Dirac derived a relativistic wave equation for the electron that naturally incorporated spin and predicted the existence of antimatter. The Dirac equation founded relativistic quantum field theory.

John Stewart Bell proved that no local hidden variable theory can reproduce all predictions of quantum mechanics, deriving testable inequalities. Bell's theorem transformed debates over quantum foundations and underpins modern quantum information science.

Image source: Bell's theorem

James Chadwick discovered the neutron, a neutral particle in the atomic nucleus, resolving puzzles about nuclear mass and spin. The neutron enabled new models of the nucleus and opened the path to nuclear fission research.

Image source: Neutron

Carl Anderson observed the positron, the electron's antiparticle, in cosmic ray cloud chamber photographs. This was the first discovery of antimatter, confirming Dirac's theoretical prediction.

Image source: Positron

Enrico Fermi's team achieved the first self-sustaining nuclear chain reaction at Chicago Pile-1 beneath Stagg Field. This milestone launched the nuclear age and was pivotal to the Manhattan Project.

Image source: Chicago Pile-1

Richard Feynman, Julian Schwinger, and Sin-Itiro Tomonaga independently developed renormalized quantum electrodynamics, explaining the Lamb shift and anomalous magnetic moment with extraordinary precision. Feynman diagrams became an essential tool of particle physics.

Image source: Quantum electrodynamics

Watson and Crick proposed the double-helix structure of DNA, aided by Rosalind Franklin's X-ray crystallography. The use of physical techniques like X-ray diffraction exemplified physics methods transforming biology.

Image source: Molecular Structure of Nucleic Acids: A Structure for Deoxyribose Nucleic Acid

Chen-Ning Yang and Robert Mills generalized gauge symmetry to non-abelian groups, creating the mathematical framework underlying the Standard Model of particle physics, including the strong and electroweak interactions.

Image source: Yang–Mills theory

Arno Penzias and Robert Wilson accidentally detected the cosmic microwave background radiation, the relic glow of the Big Bang. This discovery provided decisive evidence for Big Bang cosmology and earned them the 1978 Nobel Prize.

Image source: Discovery of cosmic microwave background radiation

Building on Weinberg, Salam, and Glashow's electroweak theory and the development of quantum chromodynamics, physicists assembled the Standard Model, classifying all known elementary particles and three of the four fundamental forces.

Image source: Standard Model

Jocelyn Bell Burnell and Antony Hewish detected the first pulsar, a rapidly rotating neutron star emitting periodic radio pulses. Pulsars confirmed the existence of neutron stars predicted by theory and became precision tools for testing general relativity.

Image source: Pulsar

Stephen Hawking applied quantum field theory to black holes, predicting they emit thermal radiation and slowly evaporate. Hawking radiation connected gravity, quantum theory, and thermodynamics, inspiring decades of research into quantum gravity.

Image source: Hawking radiation

The ATLAS and CMS experiments at CERN's Large Hadron Collider announced the discovery of a Higgs boson, confirming the mechanism that gives elementary particles mass. The discovery completed the Standard Model's particle roster.

Image source: Higgs boson

The LIGO collaboration detected gravitational waves from the merger of two black holes, exactly a century after Einstein's prediction. This opened gravitational-wave astronomy and earned the 2017 Nobel Prize in Physics.

Image source: First observation of gravitational waves

The Event Horizon Telescope collaboration released the first image of a black hole's shadow, capturing the supermassive black hole in galaxy M87. This achievement tested general relativity in the strong-field regime and showcased global scientific collaboration.

Image source: Event Horizon Telescope