"�Granted, then, that life was established and maintained on Earth. Therefore the level of radioactivity could not have been incompatible with life to begin with and it could have only fallen off with time. There is nothing that can raise the level."
"Nuclear Explosions?" suggested Trevise.
�What would that have to do with it?�
�I mean, suppose nuclear explosions took place on Earth?�
�On Earth�s surface? Impossible. There�s no record in the history of the galaxy of any society being so foolish as to use nuclear explosions as a weapon of war. We would have never survived. During the Trigellian insurrections, when both sides were reduced to starvation and desparation and when Jendippurus Khoratt suggested the initiation of a fusion reaction in-�
�He was hanged by the sailors of his own fleet. I know Galactic history��
