Non-exact solutions in general relativity
Non-exact solutions in general relativity are solutions of Albert Einstein's field equations of general relativity which hold only approximately. These solutions are typically found by treating the gravitational field,, as a background space-time,, plus some small perturbation,. Then one is able to solve the Einstein field equations as a series in, dropping higher order terms for simplicity.
A common example of this method results in the linearised Einstein field equations. In this case we expand the full space-time metric about the flat Minkowski metric, :
and dropping all terms which are of second or higher order in.
