VIEWS: 4 PAGES: 5 POSTED ON: 11/27/2011
Israeli Scientist Wins Nobel Prize for Chemistry By KENNETH CHANG An Israeli scientist won this year’s Nobel Prize in Chemistry for discovering quasicrystals, a material in which atoms were packed together in a well-defined pattern that never repeats. Recent Nobel prizes have generally split credit for scientific advances among two or three people, but this year’s chemistry prize and accompanying 10 million Swedish kronor ($1.4 million) went to a single scientist: Dan Shechtman, 70, a professor of materials science at Technion-Israel Institute of Technology in Haifa. Dr. Shechtman is also a professor at Iowa State University and a researcher at the United States Department of Energy’s Ames Laboratory. The citation from the Royal Swedish Academy of Sciences states simply, “for the discovery of quasicrystals.” Such regular but nonrepeating patterns, defined by precise rules, have been known in mathematics since antiquity, and medieval Islamic artists made decorative, nonrepeating tile mosaics, but the phenomenon was thought impossible in the packing of atoms. Yet Dr. Shechtman discovered the same type of structure in a mix of aluminum and manganese. During a sabbatical in Maryland at the National Bureau of Standards, now known as the National Institute of Standards and Technology, he took a molten glob of the metals and chilled it rapidly. The expectation was that the atoms would have been a random jumble, like glass. Yet when he examined his metal with an electron microscope, Dr. Shechtman found that the atoms were not random. His notebook recorded the exact date: April 8, 1982. Scientists believed that crystals in materials all contained repeating patterns. For example, a square lattice has fourfold symmetry. Rotate it by 90 degrees, and it looks identical. A repeating lattice with fivefold symmetry, however, is impossible. On that morning in 1982, the electrons Dr. Shechtman bounced off his aluminum-manganese alloy formed a pattern that indicated tenfold symmetry. Dr. Shechtman himself could not quite believe it. He wrote in his notebook, “10 Fold???” While a periodic lattice could not produce that pattern, a quasicrystal could. It took years for Dr. Shechtman to persuade others. During the announcement, the Nobel committee noted that one colleague initially said, “Go away, Danny,” because he thought there was a simpler explanation for what Dr. Shechtman had observed. Many scientists — notably Linus Pauling, the Nobel-winning giant of chemistry — argued vehemently that Dr. Shechtman’s data could be explained by “twinning,” where two ordinary periodic crystals are fused together at an angle. “That must have been intimidating,” said Nancy B. Jackson, president of the American Chemical Society. “When he first discovered these materials, nobody thought they could exist. It was one of these great scientific stories that his fellow scientists thought was impossible, but through time, people came to realize he was right.” Even the definition of crystal had to be changed. Previously, a crystal had been defined as having “a regularly ordered, repeating three-dimensional pattern,” according to theInternational Union of Crystallography. The new definition, adopted in 1992, states that a crystal is simply a solid with a “discrete diffraction diagram” — that is, something that produces patterns like the ones Dr. Shechtman saw. That leaves the door open for yet more different kinds of crystals in the future. Quasicrystals have since been found in many other materials, including a naturally occurring mineral from a Russian river. Materials scientists have been exploring quasicrystals because of their distinct properties — they are hard, brittle, slippery, and, unlike most metals, poor conductors of electricity. Quasicrystals have so far had modest impact in the everyday world. For example, one kind of highly resilient steel, consisting of hard steel quasicrystals embedded within softer steel, is now used in razor blades and thin needles for eye surgery. “The applications haven’t panned out,” said Patricia A. Thiel, a colleague of Dr. Shechtman at Iowa State and Ames Laboratory who also studies quasicrystals. “But they revolutionized our understanding of how atoms arrange themselves in solids. It was a scientific revolution.” Israeli leaders expressed delight and pride at the 10th Nobel Prize won by their country, which has a population of less than 8 million. Two years ago, Ada E. Yonath of the Weizmann Institute of Science in Rehovot shared the award for chemistry as well. Shimon Peres, Israel’s president, spoke by telephone to Mr. Shechtman at a news conference in Haifa and said, “Professor Shechtman, you today brought an enormous gift to the State of Israel, truly.” Prime Minister Benjamin Netanyahu also called and told him, “Every Israeli is happy today, and every Jew in the world is proud.” Dr. Shechtman was born and educated in Israel. At the news conference, he said, “The celebration is not only for the Technion and the State of Israel but also for science worldwide. There are today thousands of scientists around the world working in this field that I developed, and I am certain they all see this prize as their accomplishment and they really deserve it. Without these thousands, this science would not be where it is today.” Mr. Shechtman added, “The main lesson that I have learned over time is that a good scientist is a humble and listening scientist and not one that is sure 100 percent in what he reads in the textbooks.” Studies of Universe’s Expansion Win Physics Nobel By DENNIS OVERBYE Three astronomers won the Nobel Prize in Physics on Tuesday for discovering that the universe is apparently being blown apart by a mysterious force that cosmologists now calldark energy, a finding that has thrown the fate of the universe and indeed the nature of physics into doubt. The astronomers are Saul Perlmutter, 52, of the Lawrence Berkeley National Laboratory and the University of California, Berkeley; Brian P. Schmidt, 44, of the Australian National University in Canberra; and Adam G. Riess, 41, of the Space Telescope Science Institute and Johns Hopkins University in Baltimore. “I’m stunned,” Dr. Riess said by e-mail, after learning of his prize by reading about it on The New York Times’s Web site. The three men led two competing teams of astronomers who were trying to use the exploding stars known as Type 1a supernovae as cosmic lighthouses to limn the expansion of the universe. The goal of both groups was to measure how fast the cosmos, which has been expanding since its fiery birth in the Big Bang 13.7 billion years ago, was slowing down, and thus to find out if its ultimate fate was to fall back together in what is called a Big Crunch or to drift apart into the darkness. Instead, the two groups found in 1998 that the expansion of the universe was actually speeding up, a conclusion that nobody would have believed if not for the fact that both sets of scientists wound up with the same answer. It was as if, when you tossed your car keys in the air, instead of coming down, they flew faster and faster to the ceiling. Subsequent cosmological measurements have confirmed that roughly 70 percent of the universe by mass or energy consists of this antigravitational dark energy that is pushing the galaxies apart, though astronomers and physicists have no conclusive evidence of what it is. The most likely explanation for this bizarre behavior is a fudge factor that Albert Einstein introduced into his equations in 1917 to stabilize the universe against collapse and then abandoned as his greatest blunder. Quantum theory predicts that empty space should exert a repulsive force, like dark energy, but one that is 10 to the 120th power times stronger than what the astronomers have measured, leaving some physicists mumbling about multiple universes. Abandoning the Einsteinian dream of a single final theory of nature, they speculate that there are a multitude of universes with different properties. We live in one, the argument goes, that is suitable for life. “Every test we have made has come out perfectly in line with Einstein’s original cosmological constant in 1917,” Dr. Schmidt said. If the universe continues accelerating, astronomers say, rather than coasting gently into the night, distant galaxies will eventually be moving apart so quickly that they cannot communicate with one another and all the energy will be sucked out of the universe. Edward Witten, a theorist at the Institute for Advanced Study, Einstein’s old stomping grounds, called dark energy “the most startling discovery in physics since I have been in the field.” Dr. Witten continued, “It was so startling, in fact, that I personally took quite a while to become convinced that it was right.” He went on, “This discovery definitely changed the way physicists look at the universe, and we probably still haven’t fully come to grips with the implications.” Dr. Perlmutter, who led the Supernova Cosmology Project out of Berkeley, will get half of the prize of 10 million Swedish kronor ($1.4 million). The other half will go to Dr. Schmidt, leader of the rival High-Z Supernova Search Team, and Dr. Riess, who was the lead author of the 1998 paper in The Astronomical Journal, in which the dark energy result was first published. All three astronomers were born and raised in the United States; Dr. Schmidt is also a citizen of Australia. They will get their prizes in Stockholm on Dec. 10. Since the fate of the universe is in question, astronomers would love to do more detailed tests using supernovas and other observations. So they were dispirited last year when NASA announced that cost overruns and delays on the James Webb Space Telescope had left no room in the budget until the next decade for an American satellite mission to investigate dark energy that Dr. Perlmutter and others had been promoting for almost a decade. Indeed on Tuesday the European Space Agency announced that it would launch a mission called Euclid to study dark energy in 2019. Cosmic expansion was discovered by Edwin Hubble, an astronomer at the Mount Wilson Observatory in Pasadena, Calif., in 1929, but the quest for precision measurements of the universe has been hindered by a lack of reliable standard candles, objects whose distance can be inferred by their brightness or some other observable characteristic. Type 1a supernovae, which are thought to result from explosions of small stars known as white dwarfs, have long been considered uniform enough to fill the bill, as well as bright enough to be seen across the universe. In the late 1980s Dr. Perlmutter, who had just gotten a Ph.D. in physics, devised an elaborate plan involving networks of telescopes tied together by the Internet to detect and study such supernovae and use them to measure the presumed deceleration of the universe. The Supernova Cosmology Project endured criticism from other astronomers, particularly supernova experts, who doubted that particle physicists could do it right. Indeed, it took seven years before Dr. Perlmutter’s team began harvesting supernovae in the numbers it needed. Meanwhile, the other astronomers had formed their own team, the High- Z team, to do the same work. “Hey, what’s the strongest force in the universe?” Robert P. Kirshner of the Harvard- Smithsonian Center for Astrophysics, and a mentor to many of the astronomers on the new team, asked a reporter from this newspaper once. “It’s not gravity, it’s jealousy,” Dr. Kirshner said. In an interview with The Associated Press, Dr. Perlmutter described the subsequent work of the teams as “a long aha.” The presence of dark energy showed up in an expected faintness on the part of some distant supernovae: the universe had sped up and carried them farther away from us than conventional cosmology suggested. As recounted by the science writer Richard Panek in his recent book, “The 4% Universe, Dark Matter, Dark Energy, and the Race to Discover the Rest of Reality,” neither team was eager to report such a strange result. In January 1998, Dr. Riess interrupted preparations for his honeymoon to buck up his comrades. “Approach these results not with your heart or head but with your eyes,” he wrote in an e-mail. “We are observers after all!” In the years since, the three astronomers have shared a number of awards, sometimes giving lectures in which they completed one another’s sentences. A Nobel was expected eventually. “No more waiting!” Dr. Kirshner said Tuesday.
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