Naturally, the next question was: "How accurate is the nuclear data you used in your calculation?” As only Edward Teller is capable of doing, he replied, with a smirk-smile going from ear to ear: "Well, it's possible that the data might be off by a factor of ten.” Which way, he didn't profess to know, but I suspect that much of the audience didn't sleep too well that night. (If you're beginning to worry that you might not be sleeping too well from now on, I have to tell you that as it turned out, after careful nuclear measurements and detailed calculations were made, we were safe by far more than a factor of ten. It simply couldn't happen.)