In September 2020, cometary auroras were announced on the comet 67P/Churyumov-Gerasimenko by multiple instruments on the Rosetta spacecraft. The auroras were observed at far-ultraviolet wavelengths. Coma observations revealed atomic emissions of hydrogen and oxygen caused by the photodissociation (not photoionization, like in terrestrial auroras) of water molecules in the comet's coma. The interaction of accelerated electrons from the solar wind with gas particles in the coma is responsible for the aurora. Since comet 67P has no magnetic field, the aurora is diffusely spread around the comet.