The Friedmann equations, also known as the Friedmann–Lemaître (FL) equations, are a set of equations in physical cosmology that govern cosmic expansion...

Friedmann–Lemaître–Robertson–Walker metric (FLRW; /ˈfriːdmən ləˈmɛtrə ... /) is a metric based on an exact solution of the Einstein field equations of...

set of equations he developed known as the Friedmann equations. Alexander Friedmann was born to the composer and ballet dancer Alexander Friedmann (who...

two formalisms lead to the same field equations for General Relativity, i.e., when f(R) = R, the field equations may differ when f(R) ≠ R. In metric f(R)...

field equations (EFE; also known as Einstein's equations) relate the geometry of spacetime to the distribution of matter within it. The equations were...

metric, and its time evolution is governed by the Friedmann equations. The second Friedmann equation, a ¨ a = − 4 π G 3 ( ρ + 3 p c 2 ) + Λ c 2 3 , {\displaystyle...

scientifically originated by physicist Alexander Friedmann in 1922 with the mathematical derivation of the Friedmann equations. The earliest empirical observation...

This is a list of equations, by Wikipedia page under appropriate bands of their field. The following equations are named after researchers who discovered...

universe is poised between continued expansion and collapse. From the Friedmann equations, the value for ρ c {\displaystyle \rho _{\text{c}}} critical density...

Maxwell's equations, or Maxwell–Heaviside equations, are a set of coupled partial differential equations that, together with the Lorentz force law, form...

was Alexander Friedmann. Friedmann derived the expanding-universe solution to general relativity field equations in 1922. Friedmann's 1924 papers included...

Bijunath (2008). "Adventures in Friedmann cosmology: A detailed expansion of the cosmological Friedmann equations". American Journal of Physics. 76...

the Robertson–Walker scale factor, this is a key parameter of the Friedmann equations. In the early stages of the Big Bang, most of the energy was in the...

the familiar Euclidean geometry. The Friedmann–Lemaître–Robertson–Walker (FLRW) model using Friedmann equations is commonly used to model the universe...

solve compared to linear differential equations. This list presents nonlinear ordinary differential equations that have been named, sorted by area of...

Inflation may have provided this initial impulse. According to the Friedmann equations that describe the dynamics of an expanding universe, a fluid with...

review on Raychaudhuri equations. The Meaning of Einstein's Field Equation by John C. Baez and Emory F. Bunn. Raychaudhuri's equation takes center stage in...

Friedmann) the argument that the equations of Albert Einstein's general theory of relativity implied that the Universe is not static (see Friedmann equations)...

{\displaystyle C\ll c} for a "cold" gas. The equation of state may be used in Friedmann–Lemaître–Robertson–Walker (FLRW) equations to describe the evolution of an...

defining feature is its use of the Einstein field equations. The solutions of the field equations are metric tensors which define the topology of the...

\!} . The Friedmann equations are incorrect since they contain oversimplifications in order to make the general relativistic field equations easier to...

Einstein field equations G α β = κ T α β . {\displaystyle G^{\alpha \beta }=\kappa \,T^{\alpha \beta }.} In the above field equations, G α β {\displaystyle...

needed] The model uses the Friedmann–Lemaître–Robertson–Walker metric, the Friedmann equations, and the cosmological equations of state to describe the...

matter/energy present. This relationship can be expressed by the first Friedmann equation. In a universe without a cosmological constant, this is: H 2 = 8 π...

→ ∞ of Poincaré transformations yields Galilean transformations. The equations below are only physically valid in a Newtonian framework, and not applicable...

Kaluza–Klein Quantum gravity Solutions Cosmological: Friedmann–Lemaître–Robertson–Walker (Friedmann equations) Lemaître–Tolman Kasner BKL singularity Gödel Milne...

curvature is negative.[citation needed] From these assumptions and the Friedmann equations it follows that the scale factor must depend on time coordinate linearly...

form stars, galaxies, and clusters. Prior to structure formation, the Friedmann solutions to general relativity describe a homogeneous universe. Later...

general relativity were found by Alexander Friedmann in the early 1920s. His equations describe the Friedmann–Lemaître–Robertson–Walker universe, which...

discussing the physics implied by these equations since 1887. Early in 1889, Oliver Heaviside had shown from Maxwell's equations that the electric field surrounding...