These are the asteroids we may one day send spacecraft to, to mine them for minerals, but they're also the asteroids that may one day impact the Earth, like happened 60 million years ago with the extinction of the dinosaurs, or just at the beginning of the last century, when an asteroid wiped out almost 1,000 square miles of Siberian forest, or even just last year, as one burnt up over Russia,
有一天，我们也许能够向这些小行星， 发送宇宙飞船，从那里采矿。 但也可能，有一天这些小行星， 会撞上地球。 就像6000万年前发生的 恐龙灭绝一样， 或者像上世纪初发生的那样： 一颗小行星落下， 摧毁了西伯利亚1000平方英里的森林。 抑或像去年一样，一颗小行星在俄罗斯上空燃尽，