研究：來自太陽系邊緣的彗星讓恐龍滅絕
【摘要2021.3.15.自由】◎陳成良
Sixty-six million years ago, a huge
celestial object struck off the coast of what is now Mexico, triggering a
catastrophic "impact winter" that eventually wiped out three-quarters
of life on Earth, including the dinosaurs.
6600萬年前，一個巨大星體撞上現在的墨西哥外海，引發釀成巨災的「衝擊性寒冬」，最後導致恐龍在內的地球上4分之3物種滅絕。
A pair of astronomers at Harvard say they
have now resolved long standing mysteries surrounding the nature and origin of
the "Chicxulub impactor."
哈佛大學2位天文學家表示，他們已經解開長久以來關於「希克蘇魯伯衝擊體」（Chicxulub
impactor）的本質和來源之謎。
Their analysis suggests it was a comet
that originated in a region of icy debris on the edge of the solar system, that
Jupiter was responsible for it crashing into our planet, and that we can expect
similar impacts every 250 million to 750 million years.
他們的分析顯示，這是源自太陽系邊緣冰冷碎片區域的一顆彗星，且木星也要為此彗星撞上地球負責。類似規模的彗星撞地球頻率為每2億5000萬年到7億5000萬年。
The duo’s paper, published in the journal
Scientific Reports this week, pushes back against an older theory that claims
the object was a fragment of an asteroid that came from our solar system’s Main
Belt.
2人的論文本週在《科學報告》期刊發表，推翻了之前認為這個物體是來自太陽系「主小行星帶」小行星碎片的理論。
新聞辭典
celestial：形容詞，天的、天空的。例句：We
can observe the celestial bodies in the Museum of Natural Science.（我們可以在科學博物館內觀看天體。）
wipe out︰片語，徹底摧毀、消滅、使消失。例句︰She
has tried hard to wipe out the unpleasant memory.（她努力想抹掉這個令人不快的回憶。）
long-standing︰形容詞，長時間的、為時甚久的。例句︰Anti-nuclear
power plant is my long-standing position.（反核電是我一貫的立場。）
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