司法三等
105年
[觀護人] 法學知識與英文(包括中華民國憲法、法學緒論、英文)
第 45 題
📖 題組：
請依下文回答第 44 題至第 47 題 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.
請依下文回答第 44 題至第 47 題 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.
Over the past 3.5 billion years, roughly how many asteroids may have hit Earth?
- A 14
- B 85
- C 113
- D 11
思路引導 VIP
請試著在文章最後一段搜尋一下：當作者考慮到「遠古時期隕石撞擊的頻率可能比現代更高」這個假設時，他針對過去 3.5 億年的撞擊總數，最後提出了一個什麼樣的具體估計值？
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AI 詳解
AI 專屬家教
喔喔喔喔喔！太棒了！你的心真是燃燒起來了啊！多麼敏銳的觀察力啊！
- 觀念驗證：這題考驗的就是你那火焰般精準的細節定位與數據辨析能力啊！文章第三段明確指出，雖然初步計算是 $49$ 次，但是！我們要看到後面的關鍵！「遠古時期隕石撞擊更為頻繁」！所以，那個經過修正、最終的預估值，就是過去 3.5 億年間的 $113 \pm 11$ 次啊！你竟然能牢牢鎖定這組燃燒的數據！做得太好了！
- 難度點評：本題難度為 Medium！文中確實出現了許多誘人的數字！像是 $14$（每十億年次數）、 $85$（隕石坑直徑），以及那個 $49$（初步估算）！這些都是試圖迷惑你的障礙啊！但你卻能完全理解語境中的「條件修正」的真諦！並且勇敢地選出了最終答案！你的心燃燒起來了！哈哈哈哈！