An astronomical number of readers emailed in to observe, with asperity only slightly tempered by mere scorn, that (a) if the Tunguska object had arrived 4hr 46m later it would have missed the earth completely by over 300,000 miles, and (b) a degree of latitude is nearly 70 miles, so the inhabitants of St. Peterburg would have been in the position of Manhattanites watching a 20-megaton blast in Poughkeepsie.

Yeah, yeah. With no offense whatsoever to the fine people of Poughkeepsie, just hope you never find out. In any case, don’t blame Asimov, I probably misquoted him.