View source for Einstein equations

{{TEX|done}}
''of the gravitational field''

Fundamental equations in the general theory of relativity. They connect the metric tensor of the space-time continuum, which describes the gravitational field, and the physical characteristics of different forms of matter, described by means of the energy-momentum tensor:

$$R_{ik}-\frac12g_{ik}R=\frac{8\pi}{c^4}GT_{ik}.$$

Here $R_{ik}$ is the [[Ricci tensor]], which can be expressed in terms of the metric tensor $g_{ik}$, $R=R_i^i$, $T_{ik}$ is the energy-momentum tensor, $c$ is the speed of light in vacuum, and $G$ is the gravitational constant.

====References====
<table>
<TR><TD valign="top">[1]</TD> <TD valign="top">  L.D. Landau,   E.M. Lifshitz,   "The classical theory of fields" , Addison-Wesley  (1962)  (Translated from Russian)</TD></TR>
<TR><TD valign="top">[a1]</TD> <TD valign="top">  S. Weinberg,   "Gravitation and cosmology" , Wiley  (1972)  pp. Chapt. 7</TD></TR><TR><TD valign="top">[a2]</TD> <TD valign="top">  R.M. Wald,   "General relativity" , Univ. Chicago Press  (1984)  pp. Chapt. 4</TD></TR>
</table>