被范德华力“粘成一团”的神奇小行星

撰文凯伦·霍普金（Karen Hopkin）

翻译李轩

审校吴东远程孙雪子

From the depths of space, an asteroid hurtles toward Earth. [Well, our general vicinity.] But this is no ordinary hunk of galactic debris. Because the body of this asteroid seems to defy gravity.

此时此刻，在遥远的深空，正有一颗小行星在朝地球飞来（更确切的说，是地球所处的这一大片区域）。不过这可不是一颗普通的星系尘埃，因为它看起来似乎违反了引力的定律。

The asteroid in question is actually a kilometer-sized collection of rubble. Our rocky interloper, “1950 DA”, is rotating so rapidly that its pieces should have flung apart long ago.

实际上，这颗备受争议的小行星是一个由碎石组成的直径达上千米的巨型团块。这颗入侵的小行星名叫“1950DA”，转速非常快。按照现有理论，它应该早就分崩离析了。

Now, by analyzing the 1950 DA’s temperature and density, researchers conclude that cohesive forces called van der Waals attractions must be keeping the pieces clustered. Van der Waals forces’re well known on the small scale for their weak influence within and between molecules.

近日，研究人员通过分析1950 DA的温度和密度，揭开了它的神秘面纱。他们发现，一种被称作“范德华吸引力”的结合力，是使小行星保持现有状态的神奇之手。范德华力以一种小尺度的弱作用力而为人熟知，作用在分子内部或分子之间。

Blasting the asteroid could overcome these forces. But that might leave us with hundreds of smaller killer space rocks to dodge. The good news is, the asteroid won’t be in our area until 2880. So we have some time to figure it out.

引爆这颗小行星，就能打破范德华力的作用。不过，爆炸之后，我们可能需要同时躲避成百上千块小型陨石。好消息是，这颗小行星要到2880年才会到达我们附近。所以，我们还有时间寻找对策。