Traces of planet collision found 行星相撞遗迹被发现
文章来源:未知 文章作者:meng 发布时间:2009-08-12 00:43 字体: [ ]  进入论坛

A Nasa space telescope has found evidence of a high-speed collision between two burgeoning1 planets orbiting a young star.


In <a href=astronomical2 terms, the collision happened relatively3 recently" width="466" border="0" src="/upimg/090812/4_005640_1.jpg" />
In astronomical terms, the collision happened relatively recently

Astronomers4 say the cosmic smash-up is similar to the one that formed our Moon some four billion years ago, when a Mars-sized object crashed into Earth.

In this case, two rocky bodies are thought to have slammed(猛然关上,砰然关上) into one another in the last few thousand years.

Details are to be published in the Astrophysical Journal.

The collision involved one object that was at least as big as our Moon and another that was at least as big as Mercury.

The impact destroyed the smaller body, vaporising(蒸发) huge amounts of rock and flinging(投掷,猛冲) plumes5 of hot lava6(熔岩,火山岩) into space.

Infrared7 detectors8(红外检测器) on Nasa's Spitzer Space Telescope were able to pick up the signatures of the vaporised(汽化) rock, along with fragments of hardened lava, known as tektites(玻陨石).

Melted glass

"This collision had to be huge and incredibly high-speed for rock to have been vaporised and melted," said lead author Carey M Lisse of the Johns Hopkins University Applied9 Physics Laboratory at Laurel in Maryland, US.

"This is a really rare and short-lived event, critical in the formation of Earth-like planets and moons. We're lucky to have witnessed one not long after it happened."

Dr Lisse and his team observed a star called HD 172555, which is about 12 million years old and situated10 about 100 light-years away in the far southern constellation11(星座,星群) Pavo (the Peacock).

The astronomers used a spectrograph(光谱摄制仪) instrument on Spitzer to look for the fingerprints12 of chemicals in the spectrum13 of light from the star.

The researchers identified large amounts of amorphous14 silica(非定晶硅) - melted glass.

Silica can be found on Earth in obsidian15 rocks and tektites.

Obsidian is black, shiny volcanic16 glass. Tektites are hardened chunks17 of lava thought to have formed when meteorites18 hit the Earth.

Large quantities of orbiting silicon19 monoxide(一氧化硅) gas were also detected, created when much of the rock was vaporised. In addition, the astronomers found rocky rubble20 that was probably flung out from the planetary wreck(失事,残骇).

The two bodies must have been travelling at a speed of at least 10km/s (about 22,400mph) relative to one other before the collision.

Rocky planets form and grow in size by colliding and sticking together. This process merges21 their cores and causes some of their surfaces to be shed.

Though things have settled down in the Solar System today, impacts still occur, as was observed last month when a small comet or asteroid22 struck Jupiter.

"The collision that formed our Moon would have been tremendous, enough to melt the surface of Earth," said co-author Geoff Bryden of Nasa's Jet Propulsion Laboratory (JPL) in Pasadena, California.

"Debris23 from the collision most likely settled into a disc around Earth that eventually coalesced24(合并,联合) to make the Moon. This is about the same scale of impact we're seeing with Spitzer."

"We don't know if a moon will form or not, but we know a large rocky body's surface was red hot, warped25 and melted."

The Spitzer telescope has witnessed the dusty aftermath of large impacts before, but did not find evidence for rock that had been melted and vaporised.

Instead, large amounts of dust, gravel26, and boulder(大圆石)-sized rubble were observed, indicating collisions that were slower-paced.


1 burgeoning f8b25401f10e765adc759ee165d5c1c5     
adj.迅速成长的,迅速发展的v.发芽,抽枝( burgeon的现在分词 );迅速发展;发(芽),抽(枝)
  • Our company's business is burgeoning now. 我们公司的业务现在发展很迅速。 来自《简明英汉词典》
  • These efforts were insufficient to contain the burgeoning crisis. 这些努力不足以抑制迅速扩散的危机。 来自辞典例句
2 astronomical keTyO     
  • He was an expert on ancient Chinese astronomical literature.他是研究中国古代天文学文献的专家。
  • Houses in the village are selling for astronomical prices.乡村的房价正在飙升。
3 relatively bkqzS3     
  • The rabbit is a relatively recent introduction in Australia.兔子是相对较新引入澳大利亚的物种。
  • The operation was relatively painless.手术相对来说不痛。
4 astronomers 569155f16962e086bd7de77deceefcbd     
n.天文学者,天文学家( astronomer的名词复数 )
  • Astronomers can accurately foretell the date,time,and length of future eclipses. 天文学家能精确地预告未来日食月食的日期、时刻和时长。 来自《简明英汉词典》
  • Astronomers used to ask why only Saturn has rings. 天文学家们过去一直感到奇怪,为什么只有土星有光环。 来自《简明英汉词典》
5 plumes 15625acbfa4517aa1374a6f1f44be446     
羽毛( plume的名词复数 ); 羽毛饰; 羽毛状物; 升上空中的羽状物
  • The dancer wore a headdress of pink ostrich plumes. 那位舞蹈演员戴着粉色鸵鸟毛制作的头饰。
  • The plumes on her bonnet barely moved as she nodded. 她点点头,那帽子的羽毛在一个劲儿颤动。
6 lava v9Zz5     
  • The lava flowed down the sides of the volcano.熔岩沿火山坡面涌流而下。
  • His anger spilled out like lava.他的愤怒像火山爆发似的迸发出来。
7 infrared dx0yp     
  • Infrared is widely used in industry and medical science.红外线广泛应用于工业和医学科学。
  • Infrared radiation has wavelengths longer than those of visible light.红外辐射的波长比可见光的波长长。
8 detectors bff80b364ed19e1821aa038fae38df83     
探测器( detector的名词复数 )
  • The report advocated that all buildings be fitted with smoke detectors. 报告主张所有的建筑物都应安装烟火探测器。
  • This is heady wine for experimenters using these neutrino detectors. 对于使用中微子探测器的实验工作者,这是令人兴奋的美酒。 来自英汉非文学 - 科技
9 applied Tz2zXA     
  • She plans to take a course in applied linguistics.她打算学习应用语言学课程。
  • This cream is best applied to the face at night.这种乳霜最好晚上擦脸用。
10 situated JiYzBH     
  • The village is situated at the margin of a forest.村子位于森林的边缘。
  • She is awkwardly situated.她的处境困难。
11 constellation CptzI     
  • A constellation is a pattern of stars as seen from the earth. 一个星座只是从地球上看到的某些恒星的一种样子。
  • The Big Dipper is not by itself a constellation. 北斗七星本身不是一个星座。
12 fingerprints 9b456c81cc868e5bdf3958245615450b     
n.指纹( fingerprint的名词复数 )v.指纹( fingerprint的第三人称单数 )
  • Everyone's fingerprints are unique. 每个人的指纹都是独一无二的。
  • They wore gloves so as not to leave any fingerprints behind (them). 他们戴着手套,以免留下指纹。 来自《简明英汉词典》
13 spectrum Trhy6     
  • This is a kind of atomic spectrum.这是一种原子光谱。
  • We have known much of the constitution of the solar spectrum.关于太阳光谱的构成,我们已了解不少。
14 amorphous nouy5     
  • There was a weakening of the intermolecular bonds,primarily in the amorphous region of the polymer.分子间键合减弱,尤其在聚合物的无定形区内更为明显。
  • It is an amorphous colorless or white powder.它是一种无定形的无色或白色粉末。
15 obsidian SIsxs     
  • Obsidian is sacred to the Maoris.黑曜石是毛利人的神圣之物。
  • Once you have enough obsidian,activate the idols.一旦你有足够的黑曜石,激活神像。
16 volcanic BLgzQ     
  • There have been several volcanic eruptions this year.今年火山爆发了好几次。
  • Volcanic activity has created thermal springs and boiling mud pools.火山活动产生了温泉和沸腾的泥浆池。
17 chunks a0e6aa3f5109dc15b489f628b2f01028     
厚厚的一块( chunk的名词复数 ); (某物)相当大的数量或部分
  • a tin of pineapple chunks 一罐菠萝块
  • Those chunks of meat are rather large—could you chop them up a bIt'smaller? 这些肉块相当大,还能再切小一点吗?
18 meteorites 12efd1ed528a28fe1f7cb667a7fbc1e0     
n.陨星( meteorite的名词复数 )
  • Small meteorites have left impact craters all over the planet's surface. 这个行星的表面布满了小块陨石留下的撞击坑。 来自《简明英汉词典》
  • One theory about the existence of extraterrestrial life rests on the presence of carbon compounds in meteorites. 地球外存在生命的理论是基于陨星上存在碳化合物质这一事实的。 来自《简明英汉词典》
19 silicon dykwJ     
  • This company pioneered the use of silicon chip.这家公司开创了使用硅片的方法。
  • A chip is a piece of silicon about the size of a postage stamp.芯片就是一枚邮票大小的硅片。
20 rubble 8XjxP     
  • After the earthquake,it took months to clean up the rubble.地震后,花了数月才清理完瓦砾。
  • After the war many cities were full of rubble.战后许多城市到处可见颓垣残壁。
21 merges a03f3f696e7db24b06d3a6b806144742     
(使)混合( merge的第三人称单数 ); 相融; 融入; 渐渐消失在某物中
  • The 2012 Nobel Prize in Literature was awarded to Mo Yan"who with hallucinatory realism merges folk tales, history and the contemporary". 2012年诺贝尔文学奖得主为莫言,他“很好地将魔幻现实与民间故事、历史与当代结合在一起”。
  • A device that collates, merges, or matches sets of punched cards or other documents. 一种整理、合并或比较一组穿孔卡片或其它文档的设备。
22 asteroid uo1yD     
  • Astronomers have yet to witness an asteroid impact with another planet.天文学家还没有目击过小行星撞击其它行星。
  • It's very unlikely that an asteroid will crash into Earth but the danger exists.小行星撞地球的可能性很小,但这样的危险还是存在的。
23 debris debris     
  • After the bombing there was a lot of debris everywhere.轰炸之后到处瓦砾成堆。
  • Bacteria sticks to food debris in the teeth,causing decay.细菌附着在牙缝中的食物残渣上,导致蛀牙。
24 coalesced f8059c4b4d1477d57bcd822ab233e0c1     
v.联合,合并( coalesce的过去式和过去分词 )
  • The puddles had coalesced into a small stream. 地面上水洼子里的水汇流成了一条小溪。
  • The views of party leaders coalesced to form a coherent policy. 党的领导人的各种观点已统一为一致的政策。 来自辞典例句
25 warped f1a38e3bf30c41ab80f0dce53b0da015     
adj.反常的;乖戾的;(变)弯曲的;变形的v.弄弯,变歪( warp的过去式和过去分词 );使(行为等)不合情理,使乖戾,
  • a warped sense of humour 畸形的幽默感
  • The board has warped. 木板翘了。 来自《现代汉英综合大词典》
26 gravel s6hyT     
  • We bought six bags of gravel for the garden path.我们购买了六袋碎石用来铺花园的小路。
  • More gravel is needed to fill the hollow in the drive.需要更多的砾石来填平车道上的坑洼。
TAG标签: planet collision trace