Earth-Venus smash-up possible in 3.5 billion years: study 研究:35亿年后金星可能
文章来源: 文章作者: 发布时间:2009-06-21 01:30 字体: [ ]  进入论坛
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最新一期英国《自然》期刊上的研究报告称,一种叫做“轨道混沌”的力量可能致使地球与金星、火星等相撞,从而引发太阳系混乱。不过,这种混乱出现几率约为1/2500,且在35亿年内不会发生。上述研究结果是巴黎检测中心研究人员使用计算机数字模拟技术,对未来50亿年太阳系星球轨道不稳定性进行了上百次模拟实验后得出的。

 

A force known as orbital chaos2 may cause our Solar System to go haywire, leading to possible collision between Earth and Venus or Mars, according to a study released Wednesday.

The good news is that the likelihood of such a smash-up is small, around one-in-2500.

And even if the planets did careen into one another, it would not happen before another 3.5 billion years.

Indeed, there is a 99 percent chance that the Sun's posse of planets will continue to circle in an orderly pattern throughout the expected life span of our life-giving star, another five billion years, the study found.

After that, the Sun will likely expand into a red giant, engulfing3 Earth and its other inner planets -- Mercury, Venus and Mars -- in the process.

Astronomers4 have long been able to calculate the movement of planets with great accuracy hundreds, even thousands of years in advance. This is how eclipses have been predicted.

But peering further into the future of celestial5 mechanics with exactitude is still beyond our reach, said Jacques Laskar, a researcher at the Observatoire de Paris and lead author of the study.

"The most precise long-term solutions for the orbital motion of the Solar System are not valid6 over more than a few tens of millions of years," he said in an interview.

Using powerful computers, Laskar and colleague Mickael Gastineau generated numerical simulations of orbital instability over the next five billion years.

Unlike previous models, they took into account Albert Einstein's theory of general relativity. Over a short time span, this made little difference, but over the long haul it resulted in dramatically different orbital paths.

The researchers looked at 2,501 possible scenarios8, 25 of which ended with a severely9 disrupted Solar System.

"There is one scenario7 in which Mars passes very close to Earth," 794 kilometres (493 miles) to be exact, said Laskar.

"When you come that close, it is almost the same as a collision because the planets gets torn apart."

Life on Earth, if there still were any, would almost certainly cease to exist.

To get a more fine-grained view of how this might unfold, Laskar and Gastineau ran an additional two hundred computer models, slightly changing the path of Mars each time.

All but five of them ended in a two-way collision involving the Sun, Earth, Mercury, Venus or Mars. A quarter of them saw Earth smashed to pieces.

The key to all the scenarios of extreme orbital chaos was the rock closest to the Sun, found the study, published in the British journal Nature.

"Mercury is the trigger, and would be be the first planet to be destabilised because it has the smallest mass," explained Laskar.

At some point Mercury's orbit would get into resonance10 with that of Jupiter, throwing the smaller orb1 even more out of kilter, he said.

Once this happens, the so-called "angular momentum11" from the much larger Jupiter would wreak12 havoc13 on the other inner planets' orbits too.

"The simulations indicate that Mercury, in spite of its diminutive14 size, poses the greatest risk to our present order," noted15 University of California scientists Gregory Laughlin in a commentary, also published in Nature.



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1 orb Lmmzhy     
n.太阳;星球;v.弄圆;成球形
参考例句:
  • The blue heaven,holding its one golden orb,poured down a crystal wash of warm light.蓝蓝的天空托着金色的太阳,洒下一片水晶般明亮温暖的光辉。
  • It is an emanation from the distant orb of immortal light.它是从远处那个发出不灭之光的天体上放射出来的。
2 chaos 7bZyz     
n.混乱,无秩序
参考例句:
  • After the failure of electricity supply the city was in chaos.停电后,城市一片混乱。
  • The typhoon left chaos behind it.台风后一片混乱。
3 engulfing a66aecc2b58afaf86c4bed69d7e0dc83     
adj.吞噬的v.吞没,包住( engulf的现在分词 )
参考例句:
  • A photographer had fused the lights,engulfing the entire house darkness. 一位摄影师把电灯的保险丝烧断了,使整栋房子陷于黑暗当中。 来自《简明英汉词典》
  • A professional photographer had fused the lights,engulfing the entire house in darkness. 一位职业摄影师把保险丝烧断了使整所房子陷于黑暗当中。 来自辞典例句
4 astronomers 569155f16962e086bd7de77deceefcbd     
n.天文学者,天文学家( astronomer的名词复数 )
参考例句:
  • 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 celestial 4rUz8     
adj.天体的;天上的
参考例句:
  • The rosy light yet beamed like a celestial dawn.玫瑰色的红光依然象天上的朝霞一样绚丽。
  • Gravity governs the motions of celestial bodies.万有引力控制着天体的运动。
6 valid eiCwm     
adj.有确实根据的;有效的;正当的,合法的
参考例句:
  • His claim to own the house is valid.他主张对此屋的所有权有效。
  • Do you have valid reasons for your absence?你的缺席有正当理由吗?
7 scenario lZoxm     
n.剧本,脚本;概要
参考例句:
  • But the birth scenario is not completely accurate.然而分娩脚本并非完全准确的。
  • This is a totally different scenario.这是完全不同的剧本。
8 scenarios f7c7eeee199dc0ef47fe322cc223be88     
n.[意]情节;剧本;事态;脚本
参考例句:
  • Further, graphite cores may be safer than non-graphite cores under some accident scenarios. 再者,根据一些事故解说,石墨堆芯可比非石墨堆芯更安全一些。 来自英汉非文学 - 环境法 - 环境法
  • Again, scenarios should make it clear which modes are acceptable to users in various contexts. 同样,我们可以运用场景剧本来搞清楚在不同情境下哪些模式可被用户接受。 来自About Face 3交互设计精髓
9 severely SiCzmk     
adv.严格地;严厉地;非常恶劣地
参考例句:
  • He was severely criticized and removed from his post.他受到了严厉的批评并且被撤了职。
  • He is severely put down for his careless work.他因工作上的粗心大意而受到了严厉的批评。
10 resonance hBazC     
n.洪亮;共鸣;共振
参考例句:
  • Playing the piano sets up resonance in those glass ornaments.一弹钢琴那些玻璃饰物就会产生共振。
  • The areas under the two resonance envelopes are unequal.两个共振峰下面的面积是不相等的。
11 momentum DjZy8     
n.动力,冲力,势头;动量
参考例句:
  • We exploit the energy and momentum conservation laws in this way.我们就是这样利用能量和动量守恒定律的。
  • The law of momentum conservation could supplant Newton's third law.动量守恒定律可以取代牛顿第三定律。
12 wreak RfYwC     
v.发泄;报复
参考例句:
  • She had a burning desire to wreak revenge.她复仇心切。
  • Timid people always wreak their peevishness on the gentle.怯懦的人总是把满腹牢骚向温和的人发泄。
13 havoc 9eyxY     
n.大破坏,浩劫,大混乱,大杂乱
参考例句:
  • The earthquake wreaked havoc on the city.地震对这个城市造成了大破坏。
  • This concentration of airborne firepower wrought havoc with the enemy forces.这次机载火力的集中攻击给敌军造成很大破坏。
14 diminutive tlWzb     
adj.小巧可爱的,小的
参考例句:
  • Despite its diminutive size,the car is quite comfortable.尽管这辆车很小,但相当舒服。
  • She has diminutive hands for an adult.作为一个成年人,她的手显得非常小。
15 noted 5n4zXc     
adj.著名的,知名的
参考例句:
  • The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
  • Jim is noted for arriving late for work.吉姆上班迟到出了名。
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