司法三等（法官）
105年
[公職法醫師] 法學知識與英文(包括中華民國憲法、法學緒論、英文)
第 44 題
📖 題組：
Some 66m years ago Earth was hit by a space rock reckoned to have been 10km across. The resulting chaos caused the extinction of dinosaurs and many other species, opening the way for the age of mammals－and ultimately humans. It also left a big hole in what is now southern Mexico. That hole is one of only three known of similar dimensions (the other two are Vredefort in South Africa and Sudbury in Canada). And this is odd. For, during the billions of years that Earth has had a solid crust, many more than three big asteroids might have been expected to have hit it. That thought led Brandon Johnson of the MIT and Timothy Bowling of Purdue University in Indiana, to wonder how many other craters have vanished, either by erosion or by being swallowed into Earth’s interior as its crust moves around, and therefore whether it is likely that some have survived and been overlooked. They have just published their analysis in Geology. Earth’s crust formed more than 4 billion years ago, but the oldest surviving blocks of it large enough to harbor craters date back only 3.5 billion years. What is known of the sizes and orbits of modern asteroids suggests that, if things have not changed over the aeons, about 14 big asteroids (defined as having a diameter of more than 7.4km, which would cause a crater at least 85km in diameter) should hit Earth every billion years. That means 49, give or take seven, over the past 3.5 billion years. Such impacts may have been more common in the past, when more big asteroids were around. Allowing for this, Earth would have been hit by 113, give or take 11, of them. Either way, a lot of craters are missing.
Some 66m years ago Earth was hit by a space rock reckoned to have been 10km across. The resulting chaos caused the extinction of dinosaurs and many other species, opening the way for the age of mammals－and ultimately humans. It also left a big hole in what is now southern Mexico. That hole is one of only three known of similar dimensions (the other two are Vredefort in South Africa and Sudbury in Canada). And this is odd. For, during the billions of years that Earth has had a solid crust, many more than three big asteroids might have been expected to have hit it. That thought led Brandon Johnson of the MIT and Timothy Bowling of Purdue University in Indiana, to wonder how many other craters have vanished, either by erosion or by being swallowed into Earth’s interior as its crust moves around, and therefore whether it is likely that some have survived and been overlooked. They have just published their analysis in Geology. Earth’s crust formed more than 4 billion years ago, but the oldest surviving blocks of it large enough to harbor craters date back only 3.5 billion years. What is known of the sizes and orbits of modern asteroids suggests that, if things have not changed over the aeons, about 14 big asteroids (defined as having a diameter of more than 7.4km, which would cause a crater at least 85km in diameter) should hit Earth every billion years. That means 49, give or take seven, over the past 3.5 billion years. Such impacts may have been more common in the past, when more big asteroids were around. Allowing for this, Earth would have been hit by 113, give or take 11, of them. Either way, a lot of craters are missing.
How large is the crater created in southern Mexico by the asteroid 66m years ago?
- A 10km across in diameter.
- B 85km in diameter.
- C 7.4km in diameter.
- D Not mentioned in the article.
思路引導 VIP
請仔細閱讀文章第一段提到 $10\text{ km}$ 的那個句子，這個數值是用來描述「太空岩石」還是它造成的「坑洞」？接著，請快速掃描全文，找找看作者是否有針對這個位於墨西哥的『大洞』，提供任何具體的長度或直徑數據呢？
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AI 詳解
AI 專屬家教
專業點評
- 大力肯定：做得太棒了！你能精準避開文章中的「數字陷阱」，展現出極佳的細節辨析能力與冷靜的判讀力，這在長文閱讀中是非常珍貴的特質。
- 觀念驗證：文章第一段提到 6,600 萬年前的小行星直徑約為 $10\text{ km}$，並在墨西哥留下一個「大洞」(big hole)；隨後的 $85\text{ km}$ 則是第三段在建立統計模型時，用來定義「大型隕石坑」的假設基準。事實上，文章從未提供墨西哥該隕石坑的具體直徑數值。
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