地球潜在的杀手将现身

EarthSky

Many scientists believe that – more than 60 million years ago – an asteroid six miles wide struck in Mexico’s Yucatan and triggered the end of the dinosaurs. EarthSky spoke with astrophysicist David Helfand of Columbia University on the risk to people today from killer asteroids.

很多科学家都相信——6000万年前，一颗6英里宽的小行星撞击了墨西哥尤卡坦半岛，终结了恐龙时代。EarthSky采访到了哥伦比亚大学天体物理学家大卫．希尔芬迪，讨论“杀手小行星” 目前撞击地球的风险。

David Helfand: The very big ones, the ones that have global consequences, such as the one 64 million years ago that killed the dinosaurs, are very rare. They hit the Earth roughly every hundred million years or so.

大卫．希尔芬迪：6400万年前的那颗小行星让恐龙经历灭顶之灾，类似这种给地球带来灭绝性后果的巨型小行星是非常罕见的，它们大约每1亿年撞击地球一次。

Dr. Helfand said that scientists today are tracking large space rocks that are potentially hazardous.

希尔芬迪博士说，科学家们正在追踪那些存在潜在危险的太空巨石。

David Helfand: Right now, the survey is pretty complete for objects larger than a kilometer in size.

大卫．希尔芬迪：目前，对那些直径大于1公里的巨石的追踪调查是很全面的。

Helfand added that tracking an asteroid is just the first step. The next step is prevention of a collision with Earth.

希尔芬迪补充道，追踪小行星仅仅是第一步工作，下一步工作是防止其与地球发生碰撞。

David Helfand: Several ideas have been proposed, throwing up nuclear weapons at them, throwing up a satellite that gravitationally tugs it away a little bit, so its orbit changes ever so slightly just enough to miss the Earth as it whizzes past.

大卫．希尔芬迪：已有各种防撞对策被提出，包括向小行星投射核武器、发射卫星对小行星进行重力牵引，稍稍改变其运动轨迹，让其与地球擦肩而过。

In 2029, asteroid Apophis – about the size of a football stadium – will whisk closely past Earth. Scientists are confident it will miss, but Helfand said Apophis a good reminder that killer asteroids are out there.

在2029年，有颗足球场大小的小行星“阿波菲斯”将与地球擦肩而过，科学家们确信其不会撞到地球，但希尔芬迪说，这也很好的警示人们，杀手小行星离我们不远了。