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105年
[財經實務組] 綜合法政知識與英文(包括中華民國憲法、法學緒論、兩岸關係、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
當你在文中找到關於墨西哥坑洞的描述時，請仔細比對：文中所提供的具體數據，分別是在描述「撞擊物本身」的大小，還是「這個特定坑洞」的測量直徑呢？文中是否有給出該坑洞的確切數值？
🤖
AI 詳解
AI 專屬家教
太棒了！你的觀察力非常敏銳
- 大力肯定：這題你答得非常出色！這類題目最容易讓人掉入「數字陷阱」，你能冷靜區分天體大小與隕石坑大小的差異，展現了專業且細膩的閱讀邏輯。
- 觀念驗證：文章第一段提到撞擊地球的隕石寬約 $10\text{km}$，而第三段提到的 $85\text{km}$ 是指「大隕石」定義下所產生的坑洞最低門檻。文中雖然描述了墨西哥坑洞的背景，但從未具體標示出該坑洞的實測直徑，因此 (D) 才是正確答案。
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