The flat-Earthers often clog my notification feed on Twitter, occasionally endorsed by a minor celebrity hoping for some headlines and accusing us of not taking their evidence that the Earth is flat seriously enough. After all, how could you doubt someone that thinks they can check the curvature of the Earth by using a spirit level or by launching themselves in a homemade rocket? Advertisement If they do wish to be taken seriously, maybe flat-Earthers should stop suggesting such stupid proofs as