A massive space rock enveloped in fire and hurtling toward Earth at warp speed may be something we've only seen in movies. But asteroids do collide with planets all the time – including our own. Most of what hits Earth is small and burns up in the atmosphere. And once every few million years, a space rock big enough to cause global devastation hits. So what would we do if scientists identified a big one on a collision course with Earth?
Aug-17-2018, 20:30:59 GMT