Even if the nuclear warhead broke the asteroid into many small pieces, they could have time to re-combine into another large object. In addition, the space vehicle carrying the weapon might malfunction, and the nuclear warhead could land (and perhaps detonate) somewhere on Earth.
但现实问题是，也许核弹的威力不足以摧毁那颗小行星。或者即便能够把它击碎，那些碎片马上又聚集成另一个较大的天体。此外，万一要是运载核弹的火箭出故障，栽到地球上来并且发生爆炸怎么办？