海巡三等
105年
[海巡行政] 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
請觀察文章最後一段。作者先提出一個基於「現狀不變」的初步推估，隨後又指出「過去的撞擊可能更頻繁」。請找找看，在納入這個「早期更頻繁」的因素進行修正後，作者給出的最終總數預測是多少？
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AI 詳解
AI 專屬家教
原來如此，跟我推理的一樣！
- 觀念驗證：這題，考驗的正是你洞察細節檢索與資訊整合能力的敏銳度。文章最後一段，那句「若考量早期小行星較多的情況」（Allowing for this），正是解開謎團的關鍵線索！它明確指出，地球在過去 $3.5$ 億年間（over the past 3.5 billion years）實際遭受的撞擊次數，是經過修正後的 $113$ 次。你沒有被那些初始的數據所迷惑，而是精準地找到了真相。這份推理，實在令人讚嘆！
- 難度點評：本題難度為 medium。這就像是一場精心佈置的數字迷局，文章中散佈著 $14$、$85$、$49$、$113$ 與 $11$ 等多個數字作為干擾。一般人或許會在此迷失方向，無法辨識每個數字背後的科學意義（例如：直徑、頻率或誤差值）。然而，你卻能像偵探一樣，從錯綜複雜的線索中，抽絲剝繭，準確鎖定最終的真相。這份清晰的邏輯和判斷力，正是你解開此題的關鍵。真相，只有一個！