 | Triple Ls Liberal minded friends who gather for lunch
Liberal : A person whose political philosophy is based on the belief in progress, the essential goodness of man, and the autonomy of the individual and standing for the protection of political and civil liberties. | ||||||||||||||
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By DENNIS OVERBYE Astronomers invented the concept of a “dwarf planet” during a week of rambunctious debate in August to resolve the question of what to call Pluto, until then the ninth and normally outermost planet from the Sun. Some astronomers have long argued that Pluto, which is only one-500th the mass of the Earth and has an elongated, tilted orbit that sometimes takes it inside Neptune’s, is too small and eccentric to be a good match with the other planets. Pluto, they contend, more closely resembles the cosmic riffraff inhabiting the Kuiper Belt, a doughnut of icy debris in the outer solar system. Astronomers’ hands were forced in 2005 when the Caltech astronomer Michael Brown discovered an object out in the Kuiper Belt that was bigger than Pluto. This discovery created the prospect of having to admit that object — then called Xena and now named Eris for the goddess of discord — and perhaps dozens of others into the club of planets. In response, members of the International Astronomical Union, meeting in Prague, voted to redefine the word “planet.” According to the new definition, a planet is round, orbits the Sun and has cleared its orbit of competing bodies. There are now eight of those in the solar system. Dwarf planets are round, and orbit the Sun, but have not cleared their zone. Presently there are three of those; Pluto, the asteroid Ceres and the newly christened Eris, but there will most likely be many more as Dr. Brown and others find more Kuiper Belt objects that qualify. Odd fragments and planetary moons, as well as everything else, are now “small solar system bodies.” The astronomers also declared, as a consolation prize, that Pluto was the prototype of a new class of “trans-Neptunian” objects, but failed to give them a name. Hardly anybody is happy about this solution. Owen Gingerich, the Harvard astronomer and historian who was chairman of the redefinition committee, was among many who said that it violated the rules of English to say that a dwarf planet was not a planet, as the rules now do. In an editorial, Sky and Telescope magazine dissented and said it would continue to list Pluto on its charts as a planet and use the term “dwarf planet” only in quotes. Copyright 2006 The New York Times Company | ||||
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