Albert Einstein

Major contributions

• Explained the photoelectric effect using the photon hypothesis (1905), providing key early evidence for quantum theory and earning the 1921 Nobel Prize in Physics
• Formulated special relativity (1905), unifying space and time and showing that the speed of light is constant for all inertial observers, with the mass-energy equivalence E = mc² as a direct consequence
• Formulated general relativity (1915), describing gravity as the curvature of spacetime caused by mass and energy, replacing Newton's force-based description for strong gravitational fields
• Predicted gravitational waves (1916) and gravitational lensing, both later confirmed experimentally — lensing in 1919 and gravitational waves directly in 2015
• Made foundational contributions to quantum statistics (Bose-Einstein statistics, 1924–1925, with Satyendra Nath Bose) and raised the influential EPR paradox (1935) questioning the completeness of quantum mechanics

Named laws and equations

Law / Equation	Statement	Codex page
Einstein Photoelectric Equation	KE_max = hf − Φ	View entry
Mass-Energy Equivalence	E = mc²	View domain [PENDING FULL ENTRY]
Einstein Field Equations	G_μν + Λg_μν = 8πG/c⁴ · T_μν	View domain [PENDING FULL ENTRY]

Career

Einstein graduated from the Swiss Federal Polytechnic in Zurich in 1900 and, unable to secure an academic position, took a job as a patent examiner at the Swiss Patent Office in Bern in 1902 — the position he held during his extraordinarily productive 1905 "miracle year" (annus mirabilis), during which he published four papers, on the photoelectric effect, Brownian motion, special relativity, and mass-energy equivalence, any one of which would have secured a major reputation alone.

Einstein subsequently held academic positions at the University of Zurich, the University of Prague, and ETH Zurich, before becoming director of the Kaiser Wilhelm Institute for Physics in Berlin in 1914, where he completed general relativity in 1915. He emigrated to the United States in 1933, fleeing Nazi Germany as a Jewish scientist, and joined the Institute for Advanced Study in Princeton, New Jersey, where he remained until his death in 1955.

Key publications

• "Über einen die Erzeugung und Verwandlung des Lichtes betreffenden heuristischen Gesichtspunkt" (1905) — the photoelectric effect and the photon hypothesis
• "Zur Elektrodynamik bewegter Körper" (1905) — special relativity
• "Die Grundlage der allgemeinen Relativitätstheorie" (1916) — the full general theory of relativity

Nobel Prize

Albert Einstein received the Nobel Prize in Physics for 1921 (awarded in 1922) "for his services to Theoretical Physics, and especially for his discovery of the law of the photoelectric effect" — notably not explicitly for relativity, which remained more contested within the Nobel committee at the time.

Historical context

Einstein's 1905 photoelectric paper built directly on Max Planck's 1900 quantum hypothesis for blackbody radiation, extending the idea that energy is quantised from a mathematical device Planck himself was reportedly uneasy treating as physically real, into a literal claim that light itself consists of discrete energy packets. This was initially one of the most resisted parts of Einstein's early work — even physicists who admired his relativity papers, including Planck himself, were skeptical of the photon hypothesis for over a decade, until Arthur Compton's 1923 X-ray scattering experiments provided decisive confirmation.

Einstein's later career included a famous, sustained disagreement with Niels Bohr over the interpretation of quantum mechanics, most visibly through the 1935 EPR paper questioning whether quantum mechanics could be a complete description of physical reality — a debate not experimentally resolved until Bell test experiments decades after both men's deaths.