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## Main Question or Discussion Point

The usual derivation of the wave form equations from the GR field equations is done in the weak field, linearized approximation of the GR theory. In this limit, that ignores non-linear contributions and that gives accurate results when used to predict solutions for problems in the Newtonian limit (classical tests of relativity, more recently rates of orbital decay of binary system pulsar-see Hulse-Taylor pulsar..) the background space is the static flat Minkowski spacetime.

So this linearised EFE when used in the theory of gravitational radiation are mixing a static spacetime that by the Birkhoff's theorem doesn't allow gravitational radiation to exist(this is related to the specific features of static spacetimes that I won't go into in this post) and the interpretation that the equations similarity to wave equations and more specifically to the tranverse EM waves of Maxwell theory (see GEM equations, etc) must mean the existence of gravitational type of waves.

I see here, that at least theoretically, something doesn't fit completely, but maybe it's just my impression, I just would like to understand gravitational waves within the conceptual framework of GR. For instance, if the linearized EFE look like EM wave equations why not consider them EM radiation to begin with?

Moreover, if the background spacetime where the linearized equations are similar to wave equations forbids gravitational type of waves, is this not a sign that maybe they are not gravitational waves, but plain EM waves radiated from the mass quadrupole (which would justify the observed orbital decay in binary systems like the Hulse-Taylor pulsar?

Of course, I'm not proposing any alternative, just would like to know how is this addressed from the point of view of mainstream GR theory, or how any of my perhaps naive premises are not correctly applied to this subject (wich surely are not).

So this linearised EFE when used in the theory of gravitational radiation are mixing a static spacetime that by the Birkhoff's theorem doesn't allow gravitational radiation to exist(this is related to the specific features of static spacetimes that I won't go into in this post) and the interpretation that the equations similarity to wave equations and more specifically to the tranverse EM waves of Maxwell theory (see GEM equations, etc) must mean the existence of gravitational type of waves.

I see here, that at least theoretically, something doesn't fit completely, but maybe it's just my impression, I just would like to understand gravitational waves within the conceptual framework of GR. For instance, if the linearized EFE look like EM wave equations why not consider them EM radiation to begin with?

Moreover, if the background spacetime where the linearized equations are similar to wave equations forbids gravitational type of waves, is this not a sign that maybe they are not gravitational waves, but plain EM waves radiated from the mass quadrupole (which would justify the observed orbital decay in binary systems like the Hulse-Taylor pulsar?

Of course, I'm not proposing any alternative, just would like to know how is this addressed from the point of view of mainstream GR theory, or how any of my perhaps naive premises are not correctly applied to this subject (wich surely are not).