Thursday, October 13, 2011
Thursday, October 6, 2011
JERUSALEM (AP) — When Israeli scientist Dan Shechtman claimed to have stumbled upon a new crystalline chemical structure that seemed to violate the laws of nature, colleagues mocked him, insulted him and exiled him from his research group.After years in the scientific wilderness, though, he was proved right. And on Wednesday, he received the ultimate vindication: the Nobel Prize in chemistry.
"A good scientist is a humble and listening scientist and not one that is sure 100 percent in what he read in the textbooks," Shechtman said.
Quasiperiodical structures had been known well before the 20th-century. For example, tiles in a medieval Islamic mosque in Isfahan, Iran, are arranged in a quasicrystalline pattern. In 1961, Hao Wang asked the question of whether determining if a set of tiles admits a tiling of the plane is an algorithmically unsolvable problem or not. He conjectured that it is solvable, relying on the hypothesis that any set of tiles which can tile the plane can do it periodically (hence it would suffice to try to tile bigger and bigger patterns until obtaining one that tiles periodically). But his student, Robert Berger, constructed two years later a set of some 20,000 square tiles (now called Wang tiles) which can tile the plane but not in a periodic fashion.