Search results
Results from the WOW.Com Content Network
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.
This is clearly not enough, as there are only 14 equations (10 from the field equations and 4 from the continuity equation) for 20 unknowns (10 metric components and 10 stress–energy tensor components). Equations of state are missing. In the most general case, it's easy to see that at least 6 more equations are required, possibly more if ...
The initial value formulation of general relativity is a reformulation of Albert Einstein's theory of general relativity that describes a universe evolving over time.. Each solution of the Einstein field equations encompasses the whole history of a universe – it is not just some snapshot of how things are, but a whole spacetime: a statement encompassing the state of matter and geometry ...
In isotropic coordinates, the McVittie metric is given by [1] = (() / + / ()) + (+ / ()) () (+), where is the usual line element for the euclidean sphere, M is identified as the mass of the massive object, () is the usual scale factor found in the FLRW metric, which accounts for the expansion of the space-time; and () is a curvature parameter related to the scalar curvature of the 3-space as
These solutions are typically found by treating the gravitational field, , as a background space-time, , (which is usually an exact solution) plus some small perturbation, . Then one is able to solve the Einstein field equations as a series in h {\displaystyle h} , dropping higher order terms for simplicity.
The exact form of the metric g μν depends on the gravitating mass, momentum and energy, as described by the Einstein field equations. Einstein developed those field equations to match the then known laws of Nature; however, they predicted never-before-seen phenomena (such as the bending of light by gravity) that were confirmed later.
Given the difficulty of constructing explicit small families of solutions, much less presenting something like a "general" solution to the Einstein field equation, or even a "general" solution to the vacuum field equation, a very reasonable approach is to try to find qualitative properties which hold for all solutions, or at least for all ...
In general relativity, the van Stockum dust is an exact solution of the Einstein field equations where the gravitational field is generated by dust rotating about an axis of cylindrical symmetry. Since the density of the dust is increasing with distance from this axis, the solution is rather artificial, but as one of the simplest known ...