A very good article. The World Needs More Rebels Like Einstein
— Walter Isaacsonwww.ddhw.com Albert Einstein, as every kid knows, was a smart guy. But as we discover when we get older, smart gets you only so far. It's worth remembering, especially now, that what made Einstein special was his impertinence, his nonconformity, and his distaste for dogma.www.ddhw.com At a time when the US, worried about competition from China, is again emphasizing math and science education, Einstein's genius reminds us that a society's competitive advantage comes not from teaching the multiplication or periodic tables but from nurturing rebels. Grinds have their place, but unruly geeks change the world. And, as recent research into Einstein's personal papers shows, there's no better glimpse into his offbeat creativity than the way he puzzled out the special theory of relativity. As a child, Einstein was slow to speak. This, combined with his cheeky defiance of authority and his distaste for rote learning, led one school master to send him packing and another to dismiss him as a lazy dog.www.ddhw.com "When I ask myself how it happened that I in particular discovered the relativity theory," Einstein once said, "it seemed to lie in the following circumstance. The ordinary adult never bothers his head about the problems of space and time. But I developed so slowly that I began to wonder about space and time only when I was already grown up."www.ddhw.com Einstein alienated so many professors that he was unable to earn a doctorate, much less land an academic job. At the age of 26, he was working as a third-class examiner at the Swiss patent office in Bern. As it happens, the patent office provided a better launchpad than any university. On his way to work, Einstein would see trains rolling past the city's 12th-century clock tower, which by then had been synchronized with clocks in the nearby train station, and many of the patent applications he was reviewing proposed using signals traveling at the speed of light to sync up even more distant clocks.www.ddhw.com By May 1905, Einstein was convinced of two postulates: First, that the laws of physics, including Maxwell's equations for electromagnetic waves, were the same for all frames of reference in constant-velocity motion relative to one another, so there was no way to know whether one observer was at rest and the other in motion. Second, that the speed of light was always the same, regardless of the motion of the source.www.ddhw.com Yet the two ideas were "seemingly incompatible." He visualized a light beam racing down a railway track. The postulates, taken together, would mean that a man standing next to the track would see the light beam race by him at the same speed that a woman sitting in a railway car would see it — whether she was zooming toward the beam's source or away from it.www.ddhw.com Then something delightful happened. Einstein went to visit his best friend, Michele Besso, a brilliant but unfocused engineer he had recruited to come work at the patent office. Einstein told Besso about the dilemma. "I'm going to give it up," he said. But as they walked to work, Einstein took one of the most elegant imaginative leaps in the history of physics. "I suddenly understood the key to the problem," he later recalled. "Time cannot be absolutely defined."www.ddhw.com Imagine lightning striking at both ends of a long, fast-moving train. If the light from each strike reaches a person standing on the embankment at the midpoint of the train at the same moment, he would say the strikes happened at the same time. But a person riding inside the train at its midpoint would be a bit closer to the front lightning strike by the time the light arrived; she would say that the light from the front strike reached her first, so the strikes were not simultaneous. From that sprang Einstein's special theory of relativity. Two events that are simultaneous in one reference frame may not be simultaneous for someone moving relative to that reference frame. Therefore, time is relative depending on your state of motion. Try to catch up with a light beam and, though the speed of light remains constant, time slows down.www.ddhw.com Other scientists had come close to his insight, but they were too confined by the dogmas of the day. Einstein alone was impertinent enough to discard the notion of absolute time, one of the sacred tenets of classical physics since Newton. "Imagination is more important than knowledge," Einstein later said. Indeed, if we are ever going to unravel the further mysteries of dark matter, come up with a unified theory, or discover the true nature of energy, we should carve that proclamation above all of our blackboards.
www.ddhw.com
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哈哈哈哈 O(∩_∩)O哈哈~ 好久不来了，不小心看了一眼自己主页，发现自动关联了自己以往发过的帖，点进这个看了一眼，笑个半死。。。敢情我当初还发过这么搞笑的东西啊，我自己完全不记得了 
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发表于 2010-3-9 21:11:33
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千斤顶
发表于 2010-3-11 19:54:35
