隕石撞地球…!!
隕石撞地球…!! 不過不是現在會發生的事情. 今天早上聽同事講說有一顆asteroid, 有0.1%機會與地球相撞. 真的嚇到了…. = =||| 是下個世紀初才會發生的事情. 到時候應該可以更準確的計算到底會不會真的撞到地球. 嗯….. 這其實不會影響到我們, 只會影響到我們的下一代和下下一代……
(from newscientist.com)
Huge asteroid threatening Earth
From: Agence France-Presse From correspondents in Paris
March 03, 2006
AN asteroid capable of devastating an area the size of a sub-continent has about a one in 1000 risk of hitting Earth early next century, NASA said today.
The rock, 2004 VD17, is about 500m long and has a mass of nearly a billion tonnes.
If it hit Earth it would deliver 10,000 megatonnes of energy, equivalent to all the world’s nuclear weapons. Spotted on November 27 2004, VD17 was identified as potentially crossing Earth’s orbit, with a one in 3000 risk of collision on May 4, 2102.
Further observations and calculations have prompted the risk on that day to be upgraded to “a bit less than one in 1000″, said NASA Near-Earth Object (NEO) expert David Morrison in an emailed circular.
“The risk of an impact within the next century (is) higher than that of any other known asteroid,” he said, stressing however that the likelihood of a hit was small.
“Fortunately, it is nearly a century before the close pass from VD17. This should provide ample time to refine the orbit and, most probably, determine that the asteroid will miss the Earth.”
Collisions by large asteroids or comets are extraordinarily rare, but can be watershed events when they happen.
The reign of the dinosaurs is believed to have ended 65 million years ago by a rock that smashed into the Yucatan peninsula in Mexico.
The theory is that the impact kicked up vast clouds of dust that were borne around the globe on high-altitude winds and filtered out light and heat from the sun, inflicting climate change that changed Earth’s biodiversity.
Image: Asteroid … the impact from an asteroid this size could obliterate half a continent / supplied
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