Word: stillings
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Dates: during 1990-1999
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Einstein's general theory of relativity transformed space and time from a passive background in which events take place to active participants in the dynamics of the cosmos. This led to a great problem that is still at the forefront of physics at the end of the 20th century. The universe is full of matter, and matter warps space-time so that bodies fall together. Einstein found that his equations didn't have a solution that described a universe that was unchanging in time. Rather than give up a static and everlasting universe, which he and most other people believed...
...packets of a certain size, called quanta. It was as if radiation were packaged like sugar; you cannot buy an arbitrary amount of loose sugar in a supermarket but can only buy it in 1-lb. bags. In one of his groundbreaking papers written in 1905, when he was still at the patent office, Einstein showed that Planck's quantum hypothesis could explain what is called the photoelectric effect, the way certain metals give off electrons when light falls on them. This is the basis of modern light detectors and television cameras, and it was for this work that Einstein...
...into place before scientists succeed in solving this greatest of all puzzles. One major reason, observes Columbia University physicist Brian Greene, is that string theory developed backward. "In most theories, physicists first see an overarching idea and then put equations to it." In string theory, says Greene, "we're still trying to figure out the central nugget of truth...
...noticed that some of the vibrating strings spilling out of their equations didn't correspond to the particles they had expected. At first they viewed these mathematical apparitions as nuisances. Then they looked at them more closely; the ghosts that haunted their equations, they decided, were gravitons, the still hypothetical particles that are believed to carry the gravitational force...
...many things, says Witten, including matrix, mystery and magic. But now he has added murky to the list. Why? Not even Witten, it turns out, has been able to write down the full set of mathematical equations that describe exactly what M theory is, for it has added still more layers of complexity to an already enormous problem. Witten appears reconciled to the possibility that decades may pass before M matures into a theory with real predictive power. "It's like when you're hiking in the mountains," he muses, "and occasionally you reach the top of a pass...