Einstein field equations
Gravitational-wave astronomy can also test Maxwell-Einstein field equations. This version of the field equations predicts that spinning magnetars (i.e., neutron stars with extremely strong magnetic dipole field) should emit gravitational waves. However, quantum considerations suggest otherwise and seemingly point to a specific version of Einstein field equations. Thus, gravitational-wave astronomy could be used not only for confirmation of the existing theory, but rather it could be used for deciding which version of the Einstein field equations is correct.