So, first off, I'd just like to say that I wasn't sure exactly where to put this (before and after 1900 converge), but I decided to put it here.
So, to the point: most TLs here, from the very best to the very worst, have nucleur weapons being developed at some point between 1920 and 1960. Now, I have to admit that I'm no scientist, so it would b great to here a real scientists' input. But, just how convergent is it to have nucleur weapons in your TL?