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

Robertson–Walker (RW), or Friedmann–Lemaître (FL). When combined with Einstein's field equations the metric gives the Friedmann equation which as been developed...

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

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

{\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...

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

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

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

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...

combination greatly simplifies the equations of general relativity into a form called the Friedmann equations. These equations specify the evolution of the...

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...

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...

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

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)...

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

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...

⋅ d H {\displaystyle z\cdot d_{H}} for small z. According to the Friedmann equations, we also define a dimensionless Hubble parameter: E ( z ) = H ( z...

months later, Karl Schwarzschild found a solution to the Einstein field equations that describes the gravitational field of a point mass and a spherical...

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

"The varying cosmological constant: a new approximation to the Friedmann equations and universe model". Mon. Not. R. Astron. Soc. 476 (1): 451–458....

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

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

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

directions – is one of the core assumptions that enters into the Friedmann equations. In 2008 however, scientists working on the Wilkinson Microwave Anisotropy...

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...

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

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

was first derived from general relativity equations in 1922 by Alexander Friedmann. The Friedmann equations showed the universe might be expanding, and...

a specific solution of the field equations that describes the universe is the metric tensor called the Friedmann–Lemaître–Robertson–Walker metric, d...

{\displaystyle R_{E}} . It is the only non-trivial static solution to Friedmann's equations.[citation needed] Because the Einstein universe soon was recognized...