VOA常速英语2013--南非科学家发现首个彗星曾撞击地球的证据（在线收听）

S. African Scientists Claim Discovery of First Comet Strike 南非科学家发现首个彗星曾撞击地球的证据

JOHANNESBURG — South African researchers say they have found conclusive evidence of earth's first-ever known comet strike, about 28 million years ago. The researchers say this exciting find in rural Egypt could unlock more secrets of the universe.

South African academics say the evidence they've found indicates the comet hit the earth some 28 million years ago-in a desert in western Egypt.

南非学者表示他们发现大约2800万年前彗星撞击地球的证据—地点是埃及西部的一处沙漠。

The bits of glassy black rock left at the scene-which scientists say are comet fragments-could help unlock the secrets of our universe.

科学家称现场遗留的似玻璃般的黑色岩石为彗星碎片—这些物质可能有助于揭开我们宇宙的奥秘。

The academics presented their findings at the University of the Witwatersrand in Johannesburg this month.

学者们本月在约翰内斯堡金山大学展现了他们的研究结果。

Meteors and asteroids collide with this planet fairly frequently.

流星，小行星和这颗行星的碰撞相当频繁。

But a comet strike, said Professor David Block of the University of the Witwatersrand, is unique and exciting.

但威特沃特斯兰德大学教授大卫·布洛克表示一次彗星撞击非常罕见而且令人兴奋。

“Because a comet is this dirty snowball of not only rock, but rock mixed with ice.

“因为一颗彗星实际上就是一些冰雪物质和尘埃混杂在一起的脏雪球。

And the point is that atoms, life-giving atoms of carbon, of oxygen, of nitrogen, of argon, of neon, of krypton, are encoded within this little chemical factory from beyond the solar system," said Block.

关键是原子,蕴含生命的原子，其中的碳,氧气、氮气、氩气、氩、氪、都在这个太阳系以外的小化工厂中。”布洛克说道。

"These are grains of cosmic dust, which existed prior to our solar system forming.

“这些都是早于我们太阳系形成的宇宙尘埃颗粒。

So they contain unique secrets of the chemical composition of the cloud of gas and dust, which collapsed to form our sun and the planets around it.”

所以它们含有独特气体和灰尘化学混合成分的秘密，那是形成我们的太阳和行星围绕着的物质。”

Some scientists have theorized it may have been a comet strike that killed the dinosaurs 65 million years ago-but there is no evidence.

一些科学家认为可能是这颗彗星撞击造成6500万年前恐龙灭绝—但没有证据。

And, said Dr. Marco Andreoli, no one has seen a comet hit and lived to tell about it because they tend to fry every living thing in their path to ashes.

而马可·安德奥利博士表示没有人曾目睹过彗星撞击然后亲身讲述,因为它们会将阻挡其路的每个活物燃为灰烬。

He said, though, the evidence of this comet strike is clear to him.

尽管如此他表示这颗彗星的证据对他很明朗。

“We are looking at something of… an astronomical phenomenon,” he said.

“我们正在寻找的是一次天文现象,”他说道。

Geoscientist Jan Kramers from the University of Johannesburg said that although the scientific community is divided on his team's conclusions that the fragment is a comet, he himself is fairly certain.

约翰内斯堡大学地学科学家让·克雷默斯表示尽管科学界对于他团队表明该碎片是一颗彗星的研究结论存在分歧,但他自己则十分肯定。

“… it's a probably a comet, because it can't be anything else, coming from the outermost reaches in the solar system, traveling in the gravity of the sun and hitting the Earth by chance.

“这可能是一颗彗星,因为它不可能是别的什么,来自太阳系外层边缘,因为太阳引力的旅行及撞击地球的偶然。

What it did tells you something more," said Kramers.

它带给你的还有很多,”克雷默斯说道。

"What it did when it hit the atmosphere, it exploded.

“当击中大气层时候发生了什么,爆炸。

And that is what comets do when they hit the atmosphere.

这就是当彗星冲击大气层时候的表现。

And this explosion produces an incredible amount of heat, which can account for the Libyan desert glass which we found in that region.”

而这一爆炸产生大量的热能,从而导致我们在利比亚沙漠地区发现的玻璃状碎片。”

The researchers say they hope further study of this comet fragments will help them figure out the beginnings of our universe.

研究人员称他们希望进一步研究这颗慧星碎片，这将帮助他们探秘我们宇宙的起源。