After the thing went off, there was tremendous excitement at Los Alamos. Everybody had parties, we all ran around. I sat on the end of a jeep and bea… - Richard Feynman

Time comes, and this tremendous flash out there is so bright that I duck, and I see this purple splotch on the floor of the truck. I said, “That’s not it. That’s an after-image.” So I look back up, and I see this white light changing into yellow and then into orange. Clouds form and disappear again — from the compression and expansion of the shock wave. Finally, a big ball of orange, the center that was so bright, becomes a ball of orange that starts to rise and billow a little bit and get a little black around the edges, and then you see it’s a big ball of smoke with flashes on the inside of the fire going out, the heat. All this took about one minute. It was a series from bright to dark, and I had seen it. I am about the only guy who actually looked at the damn thing — the first Trinity test. Everybody else had dark glasses, and the people at six miles couldn’t see it because they were all told to lie on the floor. I’m probably the only guy who saw it with the human eye.

The acceptance and success of these flights is taken as evidence of safety. But erosion and blow-by are not what the design expected. They are warnings that something is wrong. The equipment is not operating as expected, and therefore there is a danger that it can operate with even wider deviations in this unexpected and not thoroughly understood way. The fact that this danger did not lead to a catastrophe before is no guarantee that it will not the next time, unless it is completely understood. When playing Russian roulette the fact that the first shot got off safely is little comfort for the next. The origin and consequences of the erosion and blow-by were not understood. They did not occur equally on all flights and all joints; sometimes more, and sometimes less. Why not sometime, when whatever conditions determined it were right, still more leading to catastrophe? In spite of these variations from case to case, officials behaved as if they understood it, giving apparently logical arguments to each other often depending on the "success" of previous flights.

The uncertainty principle “protects” quantum mechanics. Heisenberg recognized that if it were possible to measure the momentum and the position simultaneously with a greater accuracy, the quantum mechanics would collapse. So he proposed that it must be impossible.