Word: like
(lookup in dictionary)
(lookup stats)
Dates: during 1990-1999
Sort By: most recent first
(reverse)
...first step toward quantum theory came in 1900, when Max Planck, working in Berlin, discovered that the radiation from a body that was glowing red hot could be explained if light came only in 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...
...simply wasting his time, relying on a conceptual approach that was precisely backward. In contrast to just about all other physicists, Einstein was convinced that in the conflict between quantum mechanics and general relativity, it was the former that constituted the crux of the problem. "I must seem like an ostrich who forever buries its head in the relativistic sand in order not to face the evil quanta," Einstein reflected...
...know now, however, that it is Einstein's theory that ultimately fails. On extremely fine scales, space-time, and thus reality itself, becomes grainy and discontinuous, like a badly overmagnified newspaper photograph. The equations of general relativity simply can't handle such a situation, where the laws of cause and effect break down and particles jump from point A to point B without going through the space in between. In such a world, you can only calculate what will probably happen next--which is just what quantum theory is designed...
Already, in fact, theoretical physicists have succeeded in constructing a framework that offers the best hope yet of integrating gravity with nature's other fundamental forces. This framework is popularly known as string theory because it postulates that the smallest, indivisible components of the universe are not point-like particles but infinitesimal loops that resemble tiny vibrating strings. "String theory," pioneering theorist Edward Witten of Einstein's own Institute for Advanced Study has observed, "is a piece of 21st century physics that fell by chance into the 20th century...
...least one problem that had bedeviled scientists trying to meld general relativity and quantum mechanics. This difficulty arose because space lacks smoothness below subatomic scales. When distances become unimaginably small, space bubbles and churns frenetically, an effect sometimes referred to as quantum foam. Pointlike particles, including the graviton, are likely to be tossed about by quantum foam, like Lilliputian boats to which ripples in the ocean loom as large waves. Strings, by contrast, are miniature ocean liners whose greater size lets them span many waves at once, making them impervious to such disturbances...