"[O] Dispositivo do Juízo Final", uma breve história de John Gribbin, publicado em Ficção científica analógica / fato científico, Fevereiro 1985, aparentemente nunca reimpresso. O título é dado como "O Dispositivo do Dia do Juízo Final" no índice, mas apenas "Dispositivo do Dia do Juízo Final" no cabeçalho da história.
Um grande centro de pesquisa (como o Large Hadron Collider) está sendo comissionado. Infelizmente, o projeto parece estar estragado, porque o dispositivo sempre falha antes de poder ser ativado com êxito. Toda vez que os pesquisadores tentam executá-lo, ocorre alguma falha aleatória.
"OK. This is the biggest particle accelerator in creation, right? The next best thing to the Big Bang itself. We smash the beams together out there," waving vaguely at the desert view outside the windows, "and use the energy to make particles that haven't existed since the moment of creation. Only it doesn't work. Up to ten or a hundred trillion GeV, everything is hunky dory. But when we push the energy above a trillion [sic] GeV, nothing. There's no reason why it shouldn't work at higher energies, and the low energy runs check out everything in the theory. So I reckon the answer's simple. It is working, but we can't see it."
[. . . .]
"Look at what actually happens. We test all the components separately, and they check out 100 per cent. We stick it all together, we press the button, and nothing happens. So we take it all to bits, and find some trivial fault. Not once; not twice. Every time we try to make the Beast perform as specified."
De alguma forma, os pesquisadores concluem que toda vez que o experimento é executado, ele destrói a Terra. Por exemplo, se for um colisor, pode catalisar uma sopa de estrangulamento.
A teoria da história é um estado de vácuo de energia mais baixa:
"There could be lots of minima, but let's just consider two. It isn't like a U shaped valley, but an uneven W, with one side dipping much lower than the other. What I'm suggesting is that when the Universe cooled after the Big Bang, the vacuum settled down into the state corresponding to the higher valley—the higher local minimum. There is at least one even lower energy state, but we are separated from it by a little energy hill. It's in the valley next door."
He turned back to his seat, put the pen away and sat down. "When we put enough energy into our Beast in the Desert, we are pushing the particles we make up over that hill and down into the next valley. In fact, they tunnel through they get to the top, because of quantum uncertainty. But it comes to the same thing."
Como resultado, o único momento em que os pesquisadores podem observar o estado do experimento é se ele não for executado. Efetivamente, o dispositivo está podando todas as linhas do mundo em que realmente é executado.
"What I believe is, every time we run that machine it does destroy the Universe. It destroys a whole slew of universes. The only universes that continue to exist afterwards are the ones in which, for some reason, the machine didn't work. So we observe a plague of little faults that stop the machine working as planned."
Se não estou confundindo isso com outra história, os pesquisadores acabam ligando o experimento a um detector que acionará o dispositivo para funcionar se uma detonação nuclear atmosférica for detectada, com a ideia de que eles "impedirão" uma guerra nuclear por poda quaisquer linhas de mundo em que uma ocorre.
"Peace prize, Jim? How come?"
"Like this. Now we know what we are doing, we can redesign the Beast so that there are no moving parts to go wrong—everything working at the quantum level. Then, if anyone presses the button it really will be the end of the Universe. I bet you can see what will happen. Anyone who tries to do the job will have a silly accident, or just change his mind. Nobody will ever bring himself to try it, in our Universe, because in all the universes where it is tried, we won't be around any more to notice. The universe in which we are around to see what is going on just has to be one of the universes in which nothing happens. So you have to automate the Beast fully, seal it up and leave it to trigger under one condition, and one only—if it detects an upsurge in radiation consistent with the start of a nuclear war."