+Jonah Miller wrote about back of the envelope calculations today and it inspired me to finally write about the oft-quoted by fringe scientists work of Bryce DeWitt and the surprisingly less quoted work of Robert L. Forward. The link between Forward's work and Jonah's article is that Forward wrote an excellent pair of articles entitled "General Relativity for the Experimentalist" for the Proceedings of the IRE[1], (the precursor to the IEEE), and "Guidelines to Antigravity" for the American Journal of Physics[2]. In these two articles, Forward encouraged scientists and engineers to do back of the napkin general relativity by using a method of linearizing Einstein's field equations in in the weak field flat space limit so that they could be treated in the same manner as Maxwell's EM equations. So, where does Bryce DeWitt fit into the equation? In 1966 he wrote an article about using superconductors to to detect gravitomagnetic fields...