Well damn 🙃 <| sep |> I made this <| sep |> If only it had been a gif , we could have had poetry in motion . <| sep |> I ' m not convinced there IS any redshift of the standing waves inside the cavity . Nor do I see what it would accomplish in terms of thrust . Of course , without measurements we can be sure with anything , but it ' s the basis of Shawyer ' s theory . Shawyer doesn ' t talk about the red shift , but about variable speed of light , variable group velocity being more specific . The red shift would be proportional the change of group velocity , after then . Also Roger Shawyer notes in the article about his theory 4 . pdf , that the speed of light within resonator represents only fraction of speed of light in vacuum . How is it possible ? Well , a substantial fraction of microwaves spreads there in form of evanescent waves or surface plasmons , i . e . the photons coupled with free electrons of resonator material . This greatly enhances the effect of polarization to the speed of light . Whereas at free vacuum the polarization slows down the light by fraction of promile 03 opticalslower . html only , at the case of surface plasmons whole order of magnitude could be reached 10 p h y s i cistspolarizationlowering . html .