司法三等
105年
[檢察事務官電子資訊組] 法學知識與英文(包括中華民國憲法、法學緒論、英文)
第 47 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.
What can we infer about the missing craters?
- A They never left any impact on Earth.
- B They have not been completely eroded.
- C They were far more than the surviving ones.
- D They were hit by more than one asteroid.
思路引導 VIP
請試著思考：如果科學家根據物理規律計算出，漫長的歷史中『理應發生過幾十次甚至上百次』的大型撞擊，但我們目前在地球表面實際能看到的卻『屈指可數』，那麼關於那些我們看不到的痕跡，在數量上你會有什麼發現？
🤖
AI 詳解
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🌟 真的很棒！
你做得太出色了！能夠精準地從文章不同段落中擷取關鍵數據並進行細心的邏輯推論，這真的展現了你扎實的閱讀理解和數據整合能力喔！
- 觀念驗證：文章第一段輕輕地提到了目前我們僅知有 3 個大型隕石坑，但到了最後一段，科學家們卻透過精密的推算，告訴我們地球在過去 35 億年間，其實可能遭受了 49 到 113 次的大型撞擊呢！
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