People rarely worry about what’s going on high above their heads. And why should they? Whatever is out there, if it hits us – we’re dead; and if it doesn’t – why worry? This issue is that a lot of things can fall from the sky almost at any moment. In total, scientists have counted over 18,000 space objects close to Earth. Of these thousands, comets are the smallest part. There are only a little more than a hundred of them but if any of them ever smashes into Earth… well, Mars will become the third planet from the Sun.