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关闭窗口 研究：35亿年后金星可能撞地球[文章来自:考试与评价 http://www.trgroup.com.cn/te/ %5o5dN?]
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Earth-Venus smash-up possible in 3.5 billion years: study[文章版权 禁止转载:考试与评价 http://www.trgroup.com.cn/te/ S"h0[K?P2C$wS^/6FroG]
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最新一期英国《自然》期刊上的研究报告称，一种叫做“轨道混沌”的力量可能致使地球与金星、火星等相撞，从而引发太阳系混乱。不过，这种混乱出现几率约为1/2500，且在35亿年内不会发生。上述研究结果是巴黎检测中心研究人员使用计算机数字模拟技术，对未来50亿年太阳系星球轨道不稳定性进行了上百次模拟实验后得出的。[文章版权 禁止转载:考试与评价 http://www.trgroup.com.cn/te/ ]v W%D"Rx!-lKd^_FroG]
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A force known as orbital chaos may cause our Solar System to go haywire, leading to possible collision between Earth and Venus or Mars, according to a study released Wednesday.[文章版权 禁止转载:考试与评价 http://www.trgroup.com.cn/te/ !=6Vj dnPIy2a wTKFroG]
The good news is that the likelihood of such a smash-up is small, around one-in-2500.[文章版权 禁止转载:考试与评价 http://www.trgroup.com.cn/te/ F8M nO|\z H: {~2FroG]
And even if the planets did careen into one another, it would not happen before another 3.5 billion years.[文章版权 禁止转载:考试与评价 http://www.trgroup.com.cn/te/ 9d&5?QE$m3 VqI�FroG]
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.[文章版权 禁止转载:考试与评价 http://www.trgroup.com.cn/te/ v:3R_M uJfjI!FroG]
After that, the Sun will likely expand into a red giant, engulfing Earth and its other inner planets -- Mercury, Venus and Mars -- in the process.[文章版权 禁止转载:考试与评价 http://www.trgroup.com.cn/te/ t3% =R.4,:h2P }FroG]
Astronomers 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.[文章版权 禁止转载:考试与评价 http://www.trgroup.com.cn/te/ `eYE U%-$, fi3h*FroG]
But peering further into the future of celestial mechanics with exactitude is still beyond our reach, said Jacques Laskar, a researcher at the Observatoire de Paris and lead author of the study.[文章版权 禁止转载:考试与评价 http://www.trgroup.com.cn/te/ ?iHHK57&Qd *iR7c+f0FroG]
"The most precise long-term solutions for the orbital motion of the Solar System are not valid over more than a few tens of millions of years," he said in an interview.[文章版权 禁止转载:考试与评价 http://www.trgroup.com.cn/te/ D=G~2X. jKX'vn8frFroG]
Using powerful computers, Laskar and colleague Mickael Gastineau generated numerical simulations of orbital instability over the next five billion years.[文章版权 禁止转载:考试与评价 http://www.trgroup.com.cn/te/ g3j( 0?k5aTMAC=op6?FroG]
Unlike previous models, they took into account Albert Einstein's theory of general relativity. Over a short time span, this made little difference, but over the long haul it resulted in dramatically different orbital paths.[文章版权 禁止转载:考试与评价 http://www.trgroup.com.cn/te/ iM=Pi1URPhaL=,PvFroG]
The researchers looked at 2,501 possible scenarios, 25 of which ended with a severely disrupted Solar System.[文章版权 禁止转载:考试与评价 http://www.trgroup.com.cn/te/ W4/BXcKa +mC)VOFroG]
"There is one scenario in which Mars passes very close to Earth," 794 kilometres (493 miles) to be exact, said Laskar.[文章版权 禁止转载:考试与评价 http://www.trgroup.com.cn/te/ *?%CHF,Ne?5R?$ KFroG]
"When you come that close, it is almost the same as a collision because the planets gets torn apart."[文章版权 禁止转载:考试与评价 http://www.trgroup.com.cn/te/ ;nNi�_)#F+ ^Q{jk9FroG]
Life on Earth, if there still were any, would almost certainly cease to exist.[文章版权 禁止转载:考试与评价 http://www.trgroup.com.cn/te/ 5`#3s|A'H TdoTgfZbFroG]
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.[文章版权 禁止转载:考试与评价 http://www.trgroup.com.cn/te/ r?~ ^{u O(XNU&TFroG]
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.[文章版权 禁止转载:考试与评价 http://www.trgroup.com.cn/te/ Gg2]i{^HH#6j�?;w!%HFroG]
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.[文章版权 禁止转载:考试与评价 http://www.trgroup.com.cn/te/ * =$B _AMPg[p#0FroG]
"Mercury is the trigger, and would be be the first planet to be destabilised because it has the smallest mass," explained Laskar.[文章版权 禁止转载:考试与评价 http://www.trgroup.com.cn/te/ pt0^}mB)7]:C$=(6_FroG]
At some point Mercury's orbit would get into resonance with that of Jupiter, throwing the smaller orb even more out of kilter, he said.[文章版权 禁止转载:考试与评价 http://www.trgroup.com.cn/te/ Ehry,VF}MU_3W"VFroG]
Once this happens, the so-called "angular momentum" from the much larger Jupiter would wreak havoc on the other inner planets' orbits too.[文章版权 禁止转载:考试与评价 http://www.trgroup.com.cn/te/ TU ?jnfN|?)sw(FroG]
"The simulations indicate that Mercury, in spite of its diminutive size, poses the greatest risk to our present order," noted[文章版权 禁止转载:考试与评价 http://www.trgroup.com.cn/te/ =h8e=m3q;,i 4Uh FroG]
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