Hi, I would like to clarify this probably trivial little issue that is bugging me: How should dynamical solutions be understood in the context of a static spacetime? To exemplify what I mean I'll use a well known case, the source-free Maxwell eq. in their explicitly covariant form set in Minkowskian static spacetime, reduce to a EM wave eq. in the EM tensor Fab, and you can obtain solutions like the monochromatic plane wave. My confusion arises from not seeing how such dynamical solution can happen in a static spacetime (Minkowski) that is not just stationary, wich would allow time symmetry, but static so time evolution cannot even show up from crossed (dtdr..) terms. Is the wave solution time-dependency introduced thru boundary conditions? Or am I missing anything important? Thanks.