All articles starting with E
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Einstein constraint equations
The Einstein constraint equations are four of the ten Einstein field equations that contain no time derivatives, instead restricting the geometry and matter prescribed on a spacelike hypersurface.
Einstein equivalence principle
The Einstein equivalence principle (EEP) combines universality of free fall, local Lorentz invariance, and local position invariance; if it holds, gravity must be curved spacetime.
Einstein family
Einstein family: German-Jewish family of Albert Einstein from Kappel, Buchau, and Cannstatt, settled in Ulm from 1864; parents Hermann and Pauline, sister Maja, wives Mileva Marić and Elsa Einstein, children Lieserl, Hans Albert, Eduard, Nazi-era losses, Princeton household.
Einstein field equations
The Einstein field equations, or Einstein's equations, are the central equations of general relativity, relating spacetime curvature to matter and energy, published by Einstein in 1915.
Einstein manifold
An Einstein manifold is a manifold with a pseudo-Riemannian metric whose Ricci tensor is proportional to the metric, the analog of vacuum solutions of general relativity's field equations.
Einstein notation
Einstein notation, also called the Einstein summation convention, is a notational convention in which an index appearing twice in a term is implicitly summed, omitting the summation sign.
Einstein Observatory
The Einstein Observatory, originally designated HEAO-2, was a NASA X-ray astronomy satellite launched in 1978 that carried the first fully imaging X-ray telescope into space, operating until 1981.
Einstein Probe
Einstein Probe is a Chinese Academy of Sciences X-ray astronomy satellite launched on January 9, 2024, to discover high-energy transients and monitor variable X-ray sources.
Einstein relation (kinetic theory)
The Einstein relation, also called the Stokes–Einstein or Einstein–Smoluchowski relation, connects diffusion coefficient D and mobility μ by D = μkBT, the first fluctuation-dissipation theorem, derived in 1905.
Einstein ring
An Einstein ring, also called a Chwolson ring, is a ring-shaped image of a distant light source formed by gravitational lensing when source, lens, and observer align.
Einstein solid
The Einstein solid is a mathematical model treating each atom of a crystal as an identical quantum harmonic oscillator, introduced by Albert Einstein in 1907.
Einstein static universe
The Einstein static universe is a cosmological model proposed by Albert Einstein in 1917, in which a finite, motionless universe is held static by a cosmological constant.
Einstein synchronisation
Einstein synchronisation is a convention for setting distant clocks to the same time by exchanging light signals, introduced in §1 of Albert Einstein's 1905 paper on special relativity.
Einstein Telescope
The Einstein Telescope is a proposed European third-generation gravitational-wave observatory, an underground laser interferometer with 10 km arms designed to be about 10 times more sensitive than current detectors.
Einstein tensor
The Einstein tensor, or Einstein curvature tensor, is a symmetric tensor built from the metric and its curvature that appears on the left side of the Einstein field equations.
EinStein Wurfelt Nicht
EinStein würfelt nicht! (Ewn) is a 2004 dice board game by Ingo Althöfer on a 5×5 grid with six numbered stones per player; win by reaching the opponent's corner or capturing all enemy stones.
Einstein–Bergson debate
The Einstein–Bergson debate was the 6 April 1922 Paris confrontation between physicist Albert Einstein and philosopher Henri Bergson over the nature of time, relativity, and lived duration; it split intellectual communities, influenced Bergson's reputation, and remains relevant to the problem of time in quantum gravity.
Einstein–Brillouin–Keller method
The Einstein–Brillouin–Keller (EBK) method, also called torus quantization, is a semiclassical quantization scheme that assigns an action condition with a Maslov phase correction to each invariant torus of an integrable classical system.
Einstein–Cartan theory
Einstein–Cartan theory is a modification of general relativity in which spacetime has torsion tied to the spin of matter, proposed by Élie Cartan in 1922.
Einstein–Hilbert action
The Einstein–Hilbert action is the functional in general relativity whose metric variation yields the Einstein field equations, built from the Ricci scalar and introduced by Hilbert in 1915.
Einstein–Infeld–Hoffmann equations
The Einstein–Infeld–Hoffmann equations, or EIH equations, give the motion of gravitating bodies in general relativity to first post-Newtonian order, derived by Einstein, Infeld, and Hoffmann in 1938 and used in solar-system ephemerides.
Einstein–Oppenheimer relationship
The Einstein–Oppenheimer relationship was the association between Albert Einstein and J. Robert Oppenheimer, who overlapped at Princeton's Institute for Advanced Study, where Oppenheimer directed and Einstein was its most famous faculty member.
Einstein–Podolsky–Rosen paradox
The Einstein–Podolsky–Rosen (EPR) paradox is a 1935 argument by Einstein, Podolsky, and Rosen claiming quantum mechanics is incomplete; Bell tests from 1972 onward sided with quantum mechanics.
Einstein–Rosen cylindrical waves
Einstein–Rosen cylindrical waves are exact vacuum solutions of Einstein's field equations describing gravitational waves with cylindrical symmetry, introduced by Einstein and Rosen in their 1937 paper "On Gravitational Waves".
Einstein's static universe
Einstein's static universe is a cosmological solution of general relativity, presented by Albert Einstein in 1917, in which a finite, positively curved 3-sphere universe is balanced by a cosmological constant.
Einstein's thought experiments
Einstein's thought experiments (German: Gedankenexperimente) are imaginary scenarios Albert Einstein used to derive relativity, including the chasing of a light beam, the light clock, the train and embankment, and the elevator.
Einstein@Home
Einstein@Home is a distributed volunteer computing project launched in 2005 by the Max Planck Institute for Gravitational Physics, which uses idle PCs to find pulsars.
Einsteinium
Einsteinium (Element 99), symbol Es, is a synthetic radioactive actinide discovered in 1952 in the Ivy Mike thermonuclear test debris; it has no uses outside basic research.
Einstürzende Neubauten
Einstürzende Neubauten, German experimental/industrial band founded 1 April 1980 in West Berlin by Blixa Bargeld and N.U. Unruh; known for instruments made of metal and power tools, debut Kollaps (1981), pioneering crowdfunding, and 2024 album Rampen (apm: alien pop music).
Einthoven (lunar crater)
Einthoven is a 73.94 km (NASA: 69 km) IAU-named 1970 impact crater on the lunar far side at 5.06° S, 110.06° E, named for Dutch physiologist Willem Einthoven; nearby lies the young 1,143 m Einthoven cold spot crater.