Relativistic Photon Rocket-no printing

Although photons are massless ( photon rest mass m_o = 0 ) in their own rest frame and relativistically represent pure kinetic energy and do, indeed, possess relativistic momentum and hence heat energy, any directed exhaust efflux of photons from a photon rocket nozzle effectively applies Newton's 3rd Law of Motion ( 'for every action, there's an equal but opposite reaction' ) thereby providing forward rocket thrust. 

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