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  2. Cosmological constant - Wikipedia

    en.wikipedia.org/wiki/Cosmological_constant

    The cosmological constant was originally introduced in Einstein's 1917 paper entitled “The cosmological considerations in the General Theory of Reality”. [2] Einstein included the cosmological constant as a term in his field equations for general relativity because he was dissatisfied that otherwise his equations did not allow for a static universe: gravity would cause a universe that was ...

  3. Einstein field equations - Wikipedia

    en.wikipedia.org/wiki/Einstein_field_equations

    The Einstein field equations (EFE) may be written in the form: [5] [1] + = EFE on a wall in Leiden, Netherlands. where is the Einstein tensor, is the metric tensor, is the stress–energy tensor, is the cosmological constant and is the Einstein gravitational constant.

  4. Solutions of the Einstein field equations - Wikipedia

    en.wikipedia.org/wiki/Solutions_of_the_Einstein...

    where is the Einstein tensor, is the cosmological constant (sometimes taken to be zero for simplicity), is the metric tensor, is a constant, and is the stress–energy tensor. The Einstein field equations relate the Einstein tensor to the stress–energy tensor, which represents the distribution of energy, momentum and stress in the spacetime ...

  5. Friedmann equations - Wikipedia

    en.wikipedia.org/wiki/Friedmann_equations

    The second is: ¨ = (+) + which is derived from the first together with the trace of Einstein's field equations (the dimension of the two equations is time −2). a is the scale factor , G , Λ , and c are universal constants ( G is the Newtonian constant of gravitation , Λ is the cosmological constant with dimension length −2 , and c is the ...

  6. Exact solutions in general relativity - Wikipedia

    en.wikipedia.org/wiki/Exact_solutions_in_general...

    A typical conclusion from this style of argument is that a generic vacuum solution to the Einstein field equation can be specified by giving four arbitrary functions of three variables and six arbitrary functions of two variables. These functions specify initial data, from which a unique vacuum solution can be evolved. (In contrast, the Ernst ...

  7. Gödel metric - Wikipedia

    en.wikipedia.org/wiki/Gödel_metric

    The Gödel metric, also known as the Gödel solution or Gödel universe, is an exact solution, found in 1949 by Kurt Gödel, [1] of the Einstein field equations in which the stress–energy tensor contains two terms: the first representing the matter density of a homogeneous distribution of swirling dust particles (see dust solution), and the second associated with a negative cosmological ...

  8. De Sitter–Schwarzschild metric - Wikipedia

    en.wikipedia.org/wiki/De_Sitter–Schwarzschild...

    The de Sitter space is the simplest solution of Einstein's equation with a positive cosmological constant. It is spherically symmetric and it has a cosmological horizon surrounding any observer, and describes an inflating universe. The Schwarzschild solution is the simplest spherically symmetric solution of the Einstein equations with zero ...

  9. Einstein–Hilbert action - Wikipedia

    en.wikipedia.org/wiki/Einstein–Hilbert_action

    The Einstein–Hilbert action in general relativity is the action that yields the Einstein field equations through the stationary-action principle. With the (− + + +) metric signature , the gravitational part of the action is given as [ 1 ]