翻译7

Planning a Planetary Defense Against Asteroids 设计一个行星抵御小行星

In 1990, a NASA scientist named David Morrison wanted to know his chances of being killed by an asteroid.

1990年，一个名叫David Morrison的NASA科学家想知道他被小行星杀害的机会。

It seemed a bit paranoid. 这似乎有点偏执。

After all, no one had ever been killed that way, and there was only one documented meteorite injury. In 1954, an Alabama woman was sitting in her living room when an asteroid crashed through the ceiling, bounced off the radio and bruised her leg.

毕竟，没有人以这样的方式被杀害，而且只有一个关于陨石伤害人的记载。在1954年，一个小行星穿过天花板坠落，经过录音机的反弹，碰伤了一位正坐在客厅内的阿拉巴马州女子。

But just because it hadn't happened didn't mean it was impossible, and when Morrison and a colleague ran the numbers, considering both the chances of an asteroid collision and the potential damage, the results were disturbing. Though it seems counterintuitive, over a 50-year period, space rocks are about three times more likely to cause someone's death than an airplane crash and eight times more likely than a tornado.

但是仅仅因为没有被小行星伤害的事件发生并不意味着这是不可能发生的，而当Morrison和他的同事们查遍了数字记录，考虑到小行星碰撞的机会和潜在的伤害，得出的结果是令人不安的。虽然它看起来反直觉，但是，经过了50年，太空岩石致人死亡的可能性是一架飞机坠毁致人死亡的可能性的3倍，是龙卷风致人死亡的可能性的8倍。

Why? Because even though tornadoes occur fairly regularly, they kill fewer than 100 people every year. But if an asteroid the size of a 40-story building were to hit New York City - an unlikely, but not impossible, occurrence - two things would happen. Everyone would see a blinding flash, and seconds later millions of people would be dead.

为什么呢？因为尽管龙卷风频繁发生，但是它所致死的人数每年减少100人。但是，假如有40层楼高的小行星击中纽约市，一个不太可能的，但是又极有可能的两件事会发生。每个人会看到一个炫目的闪光，几秒中厚数以百万的人会死亡。

Recently the legitimacy of this threat has gone mainstream. Before, people dismissed Morrison as a crank. But now, even members of Congress are asking NASA whether we're prepared. At a hearing in March, Congress grilled NASA Administrator Charles F. Bolden Jr. and two other officials about \"threats from space.\" Bolden assured the panel that \"these are very rare events\" and that NASA isn't aware of any big rocks headed our way, but \"if it's coming in three weeks, pray.\" No one laughed.

最近， 关于这个说法的合理性已渐渐成为主流。在这之前，人们误以为Morrison是个怪人。但是现在，甚至国会成员都询问NASA是否做好了准备。在三月的一个听证会上，国会拷问NASA局长Charles F. Bolden Jr.和另外两名官员关于“太空威胁的问题”。Bolden拍板保证道：这些都是非常罕见的事件。NASA并不知悉任何巨石会袭击我们，但如果在未来三个星期内会发生，只能祈祷。没有人能高兴起来。

Scientists call these \"near-Earth asteroids,\" and our paths frequently cross. The small ones flare as harmless shooting stars. The biggest ones are thought to have caused mass extinctions.

科学家称之为“近地小行星”，和地球运行的轨道常常交叉。小光斑流星并无大碍。最大的那些行星被认为会造成生物大灭绝。

Even so, it wasn't until the early 1990s that NASA started searching for near-Earth asteroids. The first program began in earnest around 1994 when mile-wide comet fragments slammed into Jupiter, with one collision creating a five-mile fireball hotter than the sun. It was the first major impact humans had ever observed, and it got Congress's attention. Alarmed legislators responded by funding Spaceguard, a slow, ongoing effort to predict similar disasters on Earth.

即便如此，直到20世纪90年代早期，NASA才开始寻找近地小行星。第一个程序开始于1994年左右，当英里宽的彗星撞上木星，两者相撞而形成的5英里的火球比太阳还热。这是人类观测到的第一个具有影响的碰撞，而且这引起了国会的注意。这使立法者感到震惊，并要求Spaceguard予以回应，一个缓慢的，持续的在地球上预测类似灾难的

As for the survival of our species, we don't have to worry about that any time soon. Of the 1,000 near-Earth asteroids big enough to destroy civilization, 90 percent have been discovered. Impacts with these massive rocks are exceedingly rare, and none pose a threat in the foreseeable future.

至于我们的物种生存，我们没有必要太担心。1000个大到足以摧毁人类文明的近地小行星中，90%的小行星已经被探测到。这些巨石所造成的影响是罕见的，而且在可预见的未来中不会造成威胁。