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  3. For years, astronomers straggled to calculate the age of the universe. Estimates ranged from 10 to 20 billion years old, a frust

For years, astronomers straggled to calculate the age of the universe. Estimates ranged from 10 to 20 billion years old, a frust

admin2010-01-11  101
问题    For years, astronomers straggled to calculate the age of the universe. Estimates ranged from 10 to 20 billion years old, a frustratingly large spread. But that was before the launch of the Hubble Space Telescope, named after the astronomer whose discovery 70 years ago began the quest to learn the universe’s age.
   Edwin Hubble found that the galaxies (星系) within the universe are speeding away from each other at a rate proportional to their distance. That expansion rate----the Hubble constant (常数)----is the key to calculating the age and size of the universe. But pinning down the constant requires precise measurements of the distances to far-flung galaxies.
   In May, a team led by Wendy Freeman of the Carnegie Institution, of Washington, D. C., announced the result of eight years of Hubble measurements: The universe is expanding at a rate of 21 kilometers per million light-years. That translates to an age of approximately 12 billion years for the universe. similar to the value for the oldest stare.
   "After all these years," says Freeman. "we are finally entering an era of precision cosmology (宇宙论). Now we can more reliably address the broader picture of the universe’s origin, evolution, and destiny."
   Is the new number the last word? Not quite. In June, astronomers using a large array of radio telescopes reported a measurement to a distant galaxy that would make the universe 15 percent younger than Hubble’s results.
选项 A、Approximately 10 billion years old.
B、20 billion years old.
C、Approximately 12 billion years old.
D、Not quite accurate now.
答案D
解析 这道题要求学生应对文章整体有个了解，即要通读全文，才能明确问题的正确答案。文中显然提到宇宙年龄曾确定为120亿年左右，但是我们发现在最后一段却对提到这一数值并非是最后盖棺定论的标准，“Is the new number the last word? Not quite．”这句话就是这个含义。故我们只能确认D项为正确的选择。
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