THE ORIGIN OF GRAVITATIONAL LENSING - A POSTSCRIPT TO EINSTEIN 1936 SCIENCE PAPER

Gravitational lensing, now taken as an important astrophysical consequ ence of the general theory of relativity, was found even before this t heory was formulated but was discarded as a speculative idea without a ny chance of empirical confirmation. Reconstruction of some of Einstei n's research notes dating back to 1912 reveals that he explored the po ssibility of gravitational lensing 3 years before completing his gener al theory of relativity. On the basis of preliminary insights into thi s theory, Einstein had already derived the basic features of the tensi ng effect. When he finally published the very same results 24 years la ter, it was only in response to prodding by an amateur scientist.