Confirmation of the Copernican principle through the anisotropic kinetic Sunyaev Zel'dovich effect.

The Copernican principle remains largely unproven at Gpc radial scale and above. Generally, violations of this type cause a first-order anisotropic kinetic Sunyaev Zel'dovich (kSZ) effect. Here we show that, if large-scale radial inhomogeneities have amplitude large enough to explain the 'dark energy' phenomena, the induced kSZ power spectrum will be orders of magnitude larger than the Atacama cosmology telescope/South Pole telescope upper limit. This single test rules out the void model as the cause of the apparent cosmic acceleration, confirms the Copernican principle on Gpc radial scale and above, and closes a loophole in the standard cosmology.