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Albert Einstein



5. Albert Einstein:
He was a modern Merlin, conjuring up astonishing new notions of space and time, changing forever man's perception of his universe —and of himself. He fathered rel

ativity and heralded the atomic age with his famed formula E=mc2. Yet his formidable reputation never undermined his simple humanity. He spoke out courageously against social injustice. In his later years, dressed in baggy clothes, his white hair as unkempt as a sheep dog's, he helped youngsters with their geometry homework, still loved to sail, play Mozart melodies on the violin and scribble reams of doggerel. Though he has been dead nearly a quarter of a century, there are few people who do not recognize the face or name of Albert Einstein. Scientists share that adulation, for Einstein was the most eminent among them in this century and, in the eyes of some, the greatest scientist of all time. Says Nobel Laureate I.I. Rabi: "There are few ideas in contemporary physics that did not grow out of his work." Adds M.I.T.'s Irwin Shapiro: "He makes me proud to call myself a physicist." This year marks the centennial of Einstein's birth on March 14, 1879, in Ulm, Germany, and all the world seems to be joining the party. In the U.S. and Europe, in Asia and Latin America, even in the Soviet Union, where Einstein's ideas were once considered heresy, academic institutions are vying to outdo each other with special tributes. The largest commemorations will be held next month at the Institute for Advanced Study in Princeton, N.J., where Einstein spent his last 22 years, and at the Hebrew University in Jerusalem, which he helped found. "It's an avalanche effect," says Relativist Peter G. Bergmann of Syracuse University, one of Einstein's old collaborators. "Everyone wants to snatch a bit of reflected glory." Says Cambridge University's Martin Rees: "Einstein is the only scientist who has become a cult figure, even among scientists." But the centennial fever has spread far beyond academe. The U.S., West Germany and other countries are issuing special Einstein stamps. There is a spate of new books on Einstein, including two volumes of his writings published in China. Museums such as the Smithsonian Institution in Washington and the Pompidou Center in Paris are mounting Einstein exhibits. In New York City, the American Institute of Physics is assembling Einstein memorabilia for a traveling show. The East Germans are sprucing up Einstein's old summer cottage at Caputh, near Berlin. Japanese Einstein buffs are planning a pilgrimage to some of his European haunts. Television too is paying homage with several Einstein specials, including the BBC-WGBH two-hour Einstein's Universe, starring Peter Ustinov as a wide-eyed student of relativity, and PBS's 60-minute Nova documentary Einstein. Above it all is the "Einstein Observatory," an astronomical satellite launched in November to investigate stars and

other celestial objects that radiate high-energy X rays. Some of Einstein's old associates are appalled by the hoopla. Says Helen Dukas, his longtime secretary, who lovingly watches over the Einstein archives in Princeton and still places flowers in the study of his white clapboard house on Mercer Street: "Do you know what he would say? 'You see, they are still taking pieces out of my hide.' " Philosopher Paul Schilpp, who is helping arrange a centennial symposium at Southern Illinois University, acknowledges that Einstein "would hate all this uproar." What has aroused Einsteinophiles especially is a 12-ft.-high bronze statue of the physicist that will be unveiled in April by the National Academy of Sciences on Washington's Constitution Avenue. Critics have attacked Sculptor Robert Berks for his "bubble gum" style, the astrological connotation of the star-studded base and the statue's cost (at least $1.6 million). Others insist that no statue could really be appropriate; Einstein, after all, was so opposed to posthumous veneration that he willed his ashes to be scattered at an undisclosed place. Constantly called upon to pose for photographers, painters and sculptors (including Berks), he once gave his occupation as "artist's model." Perhaps the most meaningful tribute to Einstein is entirely unplanned: the renaissance of interest in his scientific work. Before his death in 1955 at 76, Einstein had called himself a "museum piece," a fossil who had long since slipped out of the mainstream of physics. Indeed, his greatest work, general relativity, fell into an intellectual limbo. Explains University of Texas Physicist John Wheeler: "For the first half-century of its life, general relativity was a theorist's paradise but an experimentalist's hell. No theory was more difficult to test." Physicists turned to other concepts, mostly concerning atomic structure, that could be more easily verified and had more applications. Now that view has undergone a dramatic change. Says West German Physicist Carl Friedrich von Weizsacker: "Einstein's true greatness lies in the fact that he remains relevant today, in spite of the breakthroughs that have occurred since his death." Indeed, it is many of those breakthroughs that have contributed to the Einstein revival. Since the early 1960s, astronomers have been opening up an entirely new universe, aided by technology only vaguely dreamed of in Einstein's day: giant radio antennas that can "see" hitherto unknown sources of energy in space, orbiting satellites that scan the heavens high above the obscuring atmosphere, and atomic clocks so accurate they lose or gain barely a billionth of a second in a month.

- Albert Einstein’s Theories:
This unexpected world includes enigmatic objects called quasars. Radiating prodigious amounts of energy, they are visible on earth despite the fact that they may be the most distant objects in the universe. Pulsars, or neutron stars, have

also been detected; these highly compressed cadavers of massive stars usually signal their existence by their highly regular radio beeps. Even stranger are the giant stars that may have in effect gone down the cosmic drain: those elusive black holes, with gravitational fields so powerful that not even light can escape them. Astronomers have also picked up what may be the echo of the Creation. Coming from everywhere in the skies, and in a sense from nowhere at all, these faint microwaves appear to be the lingering reverberations of the Big Bang, the cataclysmic explosion in which the universe was apparently born 15 billion to 20 billion years ago. Einstein, in his time, could have had little inkling of this astronomical revolution. Yet to understand phenomena of such cosmic proportions, scientists must rely on his theoretical masterwork: the general relativity theory. Unfolded in 1916 to an astonished and largely uncomprehending scientific community, it is Einstein's complex and subtle yet beautifully elegant mathematical explanation of nature's most pervasive—and paradoxically, its weakest—force: gravity. As a direct consequence of the recent astronomical discoveries and a host of new and precise measuring techniques, general relativity is finally enjoying boom times. Thus Einstein, a genius in his own age, remains a powerful intellectual force in this time as well. The number of learned papers on general relativity has risen from only a handful a few years ago to some 600 or 700 a year. The relativistic revival can also be seen in the spirited competition by scientists around the world to be the first to detect the gravity waves, which, Einstein said, are the vehicle by which gravitational force is transmitted, just as light or radio waves are the carriers of electromagnetic force. Scientists are also conducting ever more sensitive tests of Einstein's theory. M.I.T.'s Shapiro and his colleagues have been sending radio signals past the rim of the sun, bouncing them off other planets and clocking their return to earth to an accuracy of better than a millionth of a second. The object: to see if solar gravity slows the signals down by the amount forecast by Einstein. So far, general relativity has passed these and other tests without exception. Says Yale Physicist Feza Gursey: "Einstein's theories tend to become stronger with time."

- Early Life Of Einstein:
In his earliest years, Einstein showed no obvious sign of genius; he did not begin talking until the age of three. At Munich's Luitpold Gymnasium (high school), he bridled at the inflexible system of rote learning and the drill-sergeant manner of his teachers, annoying them with his rebellious attitude. Said one: "You will never amount to anything." Yet there were also some hints of the man to be. At five, when he was given a compass, he was fascinated by the mysterious force that must be influencing its needle. He went through a deeply religious period before adolescence, berating his freethinking father, a manufacturer of electrochemical products, for straying from the

path of Jewish orthodoxy. But this phase passed soon after he began studying science, math and philosophy on his own. He was especially enamored of a basic math text—his "holy geometry booklet." At 16, he devised one of his first "thought experiments." These can only be done in the mind, not in a laboratory, and would eventually lead him to his stunning theories. In this case, he imagined what a light wave would look like to an observer riding along with it. Within a year after his father's business failed and the family moved to Northern Italy to start anew, Einstein dropped out of school and renounced his German citizenship. To shake off the bitter memories of the Munich school, he spent a year hiking in the Apennines, visiting relatives and touring museums. He then decided to enroll in the famed Swiss Federal Institute of Technology in Zurich. Though he failed the entrance exam—because of deficiencies in botany and zoology, as well as in languages other than German—he was admitted after a year's study at a Swiss high school. (Eventually he became a Swiss citizen.) Yet Einstein's rebelliousness continued. He cut lectures, read what he pleased, tinkered in school labs and incurred the wrath of his teachers. Mathematician Hermann Minkowski, who later made valuable contributions to Einstein's new physics, called him a "lazy dog." Only scrupulous notes kept by a classmate, Marcel Grossmann, enabled Einstein to cram successfully for his two major exams and to graduate in 1900. Having antagonized his professors, Einstein failed to obtain a university teaching post. He eked out a living by doing calculations for an astronomer, tutoring and substituting as a teacher. At 23 he got a job as an examiner with the Swiss Patent Office in Bern. His title: technical expert, third class. His pay: a modest 3,500 francs, then about $675, a year. Still, as Einstein said, the post "in a way saved my life." It enabled him to marry a fellow physics student Mileva Marie, from Serbia. In reviewing patent applications, he also learned to get to the heart of a problem and to decide quickly if ideas were valid. That left him time to think about physics.

There was plenty to ponder. For more than two centuries, the basic laws of motion and gravitation postulated by Isaac Newton had prevailed. They were more than adequate tc describe planetary movements, the behavior of gases and other everyday physical phenomena. But by the end of the 19th century serious cracks had developed in the Newtonian edifice. For example, Newton had regarded light as a stream of particles ("corpuscles"). Experiments had already shown that light was wavelike. Perhaps more significant, the English scientist Michael Faraday and the Scot James

Clerk Maxwell had demonstrated that electromagnetism, which includes light, comprised a class of phenomena that did not fit easily into the Newtonian system. If light consisted of waves, however, how were they transmitted? Scientists realized that space was largely empty of conventional matter. So, to carry light over such vast distances as that between sun and earth, they postulated the existence of a tenuous, invisible substance called the ether. To detect the ether, the Americans Albert Michelson and Edward Morley performed a clever experiment in 1887. As the earth moved around the sun at about 30 km (19 miles) per second, the motion-would generate an ether "wind" in the opposite direction, just as a bicyclist pedaling on a calm day creates a wind that blows into his face. Thus the velocity of light should be greater when light moves with this wind, or across it, than against it. To test the ether theory, Michelson and Morley constructed an ingenious rotating apparatus with a light source and mirrors. To their amazement, they found that no matter in what direction light was beamed, its velocity remained exasperatingly constant. Could it be that the ether did not exist? In an attempt to preserve the ether, Irish Physicist George FitzGerald offered a novel theory: perhaps motion through the ether causes an object to shrink slightly in the direction of its travels. Indeed, by his argument, the contraction would be just enough to compensate for the change in the velocity of light caused by the ether wind. Thus the wind would be impossible to detect. Putting the theory into elegant mathematical form, the Dutch physicist Hendrik Lorentz added another idea: permeating the structure of all matter, the ether would also slow down clocks traveling through it—in fact, just enough so light's speed would always seem constant. Even to scientists of the day, these theories seemed patchwork: they dealt with nagging questions, but in an artificial and contrived way. Yet they contained seeds of truth. Science was groping toward the answer to the ether dilemma and the limitations of Newtonian physics. And even without Einstein, someone eventually would have solved the puzzle. Still, the intuitive flash did not occur to any of the scientific greats of the day, but to the 26-year-old patent examiner on the fringes of physics. That insight was shown in two remarkable papers that appeared during 1905 in the German scientific journal Annalen der Physik. The title of the first — "On the Electrodynamics of Moving Bodies" — did not begin to reflect its eventual significance. Later it would become known as Einstein's special theory of relativity. Einstein boldly disregarded the notion of the ether. Then he went on to state two postulates: 1) An experiment can detect only relative motion, that is, the motion of one observer with respect to an other. 2) Regardless of the motion of its source, light always moves through emp ty space at a constant speed (this seems to violate common sense, which suggests that light projected forward from a moving spacecraft,

like a bullet fired from a plane, would travel at a speed equal to its velocity plus that of the craft). From these statements, using thought experiments and simple mathematics, Einstein made deductions that shook the central ideas of Newtonian physics.

In demolishing New ton's basic assumption that time is absolute, that it is universally the same, and that it flows steadily from the past toward the future, Einstein used the following thought experiment: an observer standing next to a railroad embankment sees two bolts of lightning strike the tracks at the same time and thus concludes that they occurred simultaneously, one far to the east, the other an equal distance to the west. Just as the bolts hit, a second observer passes directly 'in front of him on a train moving at high speed from east to west.

To the second observer, the bolts do not seem to strike simultaneously. Rea son: because he is moving away from the bolt in the east, its light takes slightly longer to reach him. Similarly, because he is moving toward the bolt in the west, its light reaches him earlier. Thus what the stationary observer sees as simultaneous lightning strikes, the moving observer sees as a flash in the west followed by one in the east. If, on the other hand, the bolts had struck at different times, it could well have been the moving observer who saw them simultaneously and the man along the tracks who thought that they did not occur at the same time. In any case, the question remains: Which of these views is wrong? Nei ther, said Einstein. Measurements of time depend on the choice of the reference frame — in this case, the train or the point along the tracks. By similar reasoning, Einstein also showed that the Newtonian concept of ab solute length was obsolete.



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