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彗星撞地球,或许并不糟

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小编摘要:彗星撞地球,也许就是世界末日的到来吧!即便不是如此,那么也会是人类的一场巨大灾难。可是慕尼黑大学的研究者们却发现,事实或许并非如此糟糕!

导读:大家都知道,一颗巨大的彗星撞击地球不会是件好事,会导致地震、海啸、大风暴等灾害的发生。然而科学家们发明的一种新的模型预测,这样的撞击带来的后果也许并不像人们之前想象的那么严重。这是由于之前的预测都是以地球是个光滑的球体为前提,可是地球实际上却是一个布满了山峰沟壑的椭圆体,这些山峰沟壑能够传播撞击带来的辐射波,降低灾害的危险性。


It’s well known that a large meteorite hitting the Earth would not be good news, as it would cause earthquakes, tsunamis and firestorms.

However, scientists have created a new model for predicting the impact of such collisions that shows the devastation wouldn’t be anywhere near as severe as previously thought.

Scientists from the University of Munich argue that previous predictions of impact damage assume the Earth is smooth and spherical – but it’s actually elliptical with huge peaks and troughs, which would help to diffuse the resulting seismic waves.

Research leader Matthias Meschede said: ‘After a meteorite impact, seismic waves travel outward across the Earth's surface like after a stone is thrown in water.

'For the Earth, these calculations are usually made using a smooth, perfect sphere model, but we found that the surface features of a planet or a moon have a huge effect on the aftershock a large meteorite will have, so it's extremely important to take those into account.’

Mr Meschede’s team used their model to produce a fresh simulation of the meteorite crash that wiped out the dinosaurs 65million years ago and caused the huge Chicxulub crater, which can be seen from space.

The space rock was the mass of Mountt Everest – when its tip hit Mexico the tail was still 35,000 feet up.

It was the equivalent of two million hydrogen bombs going off – yet the Munich team have downplayed its effects, claiming that the tsunamis and earthquakes that resulted were enough to wipe out the dinosaurs, but the shock-waves' that caused them would have been weakened by the planet’s landscape.

Mr Meschede added: 'Our results go beyond Chicxulub. We can, in principle, now estimate how large a meteorite would have to have been to cause catastrophic events. Our model can be used to estimate the magnitude and effect of other major impacts in Earth's past.'

Tomorrow an asteroid the size of four football pitches called 2005 YU55 will pass between the Earth and Moon.

If something that size was to slam into the Earth it would cause a 2.5mile-wide crater, a magnitude 7.0 earthquake, and if it hit water a 70-foot high tsunami would spread within 60 miles of the crash site.

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2011-11-08 11:28 编辑:lilylikelily
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