I had the following question how are the Schwarchzild metric that describes a spherically symmetric matter distribution (such as a star) be compatible with the FRW metric that describes the 'overall universe' that the star resides in/is part of its matter distribution? Then we say that FRW solution is not applicable in small distances because the Universe is no longer homogeneous and isotropic. How did this happen? we started from an homogeneous and isotropic universe and we ended up (because of the very small perturbations or inner interactions?) with structure formation and the "destruction" of what we started with?