Changes

where <math>R_{\mu\nu}</math> is Ricci tensor, <math>R</math> is its contraction, <math>g_{\mu\nu}</math> is metric tensor of spacetime, and <math>T_{\mu\nu}</math> is stress-energy tensor.  

where <math>R_{\mu\nu}</math> is Ricci tensor, <math>R</math> is its contraction, <math>g_{\mu\nu}</math> is metric tensor of spacetime, and <math>T_{\mu\nu}</math> is stress-energy tensor.  

Einstein added this '''cosmological constant''' to his field equation to make the universe stationary (neither expanding nor contracting) which it works when the '''cosmological constant''' has so called Einstein value  

Einstein added the term with '''cosmological constant''' to his gravitational field equations in order to allow the existence of a homogeneous static solutions in the presence of matter, i.e. to make the universe stationary (neither expanding nor contracting). This works when the '''cosmological constant''' has so called Einstein value:

:<math>\Lambda_E=4\pi G \rho/c^2</math>,  

:<math>\Lambda_E=4\pi G \rho/c^2</math>,  

where <math>G</math> is Newtonian gravitational constant, <math>\rho</math> is density of space, and <math>c</math> is speed of light in [[vacuum]].

where <math>G</math> is Newtonian gravitational constant, <math>\rho</math> is [mass] density of space, and <math>c</math> is speed of light in [[vacuum]].

==Historical background==

==Historical background==