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(单词翻译)
This is Scientific American's 60-Second Science. I'm Christopher Intagliata. Got a minute?
Galileo first spotted1 Saturn2's rings 400 years ago. But since then, scientists have been stumped3 about how they got there. Because the rings are almost pure water ice—and material in the outer solar system is generally an ice-rock mix. But a new analysis in the journal Nature may have solved the mystery.
Today, Saturn's only massive moon is Titan. But Saturn's fellow gas giant planet Jupiter has four big moons. So Saturn might once have had more—one of which could have had a rocky core surrounded by a shell of water ice. That moon would have interacted with a disk of gas surrounding Saturn at the time, dragging its orbit closer and closer.
As the moon spiraled in, tidal forces would have flexed4 its icy shell, stripping off chunks5 to build rings a thousand times more massive than Saturn has today. Eventually, ice boulders6 in the rings would have smashed into each other, spreading out the rings, and causing the outer edge to spawn7 icy moons—the small ones we find orbiting Saturn today.
As for that ancient moon's rocky core? Saturn probably swallowed it up. Leaving Titan unique. And leaving scientists with a puzzle they finally may have solved.
Thanks for the minute. For Scientific American's 60-Second Science, I'm Christopher Intagliata.
1 spotted | |
adj.有斑点的,斑纹的,弄污了的 | |
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2 Saturn | |
n.农神,土星 | |
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3 stumped | |
僵直地行走,跺步行走( stump的过去式和过去分词 ); 把(某人)难住; 使为难; (选举前)在某一地区作政治性巡回演说 | |
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4 flexed | |
adj.[医]曲折的,屈曲v.屈曲( flex的过去式和过去分词 );弯曲;(为准备大干而)显示实力;摩拳擦掌 | |
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5 chunks | |
厚厚的一块( chunk的名词复数 ); (某物)相当大的数量或部分 | |
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6 boulders | |
n.卵石( boulder的名词复数 );巨砾;(受水或天气侵蚀而成的)巨石;漂砾 | |
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7 spawn | |
n.卵,产物,后代,结果;vt.产卵,种菌丝于,产生,造成;vi.产卵,大量生产 | |
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