violating the laws of nature -- 5/2/18
Today's selection -- from The Accidental Universe by Alan Lightman. Violating the laws of nature:
"In the twentieth century, with the discovery of laws for how time and space contract and expand with motion and gravity (relativity), laws for the microscopic behavior of subatomic particles (quantum mechanics), and laws for the forces that hold atomic nuclei together (quantum chromodynamics), physicists have codified their understanding and faith in the laws of nature. So strong is that faith that scientists are profoundly disturbed when it appears that one of the established laws
has been violated. The conservation of energy is such a law. This law was discovered in the mid-nineteenth century as the result of independent experiments by the German physician Julius Robert Mayer and by James Prescott Joule, the British scion of a wealthy brewing family, who furnished his laboratory from inherited money.
"As discussed in 'The Spiritual Universe,' the law says that although energy can change from one form to another, the total amount of energy in an isolated container remains constant. Over the last couple of centuries, we have discovered how to quantify the amount of energy in motion, in heat, in gravity, and in many other phenomena, and the total in a closed system doesn't change. If you put a bomb that has eleven units of chemical energy in an impenetrable box and detonate the bomb, a split second later the chemical energy of the bomb will have transformed into the light and the motion and the heat of the flying debris, but the total amount of energy will be still be eleven units. The conservation of energy is one of the sacred cows of science. Since the mid-nineteenth century, it has been deeply embedded in all the other laws of science.
"In 1914, physicists discovered what appeared to be a violation of the law of conservation of energy. Certain kinds of radioactive atoms were found to spit out subatomic particles called 'beta particles.' The energy of such an atom before and after the emission could be measured. According to the law of conservation of energy, the energy of the beta particle should equal the difference in atomic energies before and after, just as the difference in bank balances at two different times should be equaled by the total expenditure of money during that period. Against these expectations, the energy of the beta particle was found to vary all over the place, sometimes being one number and sometimes another. Some physicists repeated the measurements and got the same upsetting results. Others argued that the beta particles were indeed emitted with the correct energy but lost some of it in random collisions with other atoms before being measured. A small group of distinguished physicists reluctantly proposed that perhaps the law of the conservation of energy was valid only in an average sense but not for each event in each atom.
|Wolfgang Pauli in front of a blackboard with P Jordan
"In December 1930, just before a major scientific conference in Europe, the Austrian prodigy Wolfgang Pauli wrote a letter to his colleagues about the troubling dilemma of beta emission. His letter begins: 'Dear Radioactive Ladies and Gentlemen ... I have hit upon a desperate remedy to save the ... law of conservation of energy.' Pauli then goes on to propose that when a radioactive atom emits a beta particle, it also emits another kind of particle, previously unknown and now called a neutrino, and the sum of the energies of the neutrino and the beta particle correctly equals the difference in atomic bank balances. In other words, some of the energy expenditures had been accounted for but others had not. The proposal of a new kind of fundamental particle in physics is not taken lightly. 'I agree that my remedy could seem incredible because one should have seen those [neutrinos] much earlier if they really exist. But only the one who dares can win . . ... Pauli ends his letter with an apology to his colleagues. He will have to miss the conference in Tubingen because he is 'indispensable' at a ball in Zurich.
"Physicists weaned on the conservation of energy jumped at Pauli's invisible neutrino and even began building it into new theories of radioactive atoms. The neutrino remained only a hopeful dream until 1956, when American physicists Clyde Cowan and Frederick Reines detected it at the Savannah River nuclear reactor in South Carolina. And the law of the conservation of energy remained supreme."