Bit of a broad statement that "they are about as usefull as a chocolate fireplace"? Given that without a bit of thinking we would still be having the family evening meal in a cave.

Re world suddenly ending. It would be no point in pointing out the impact history that is still visible on this planet or new ones cropping up on other bodies we happen to be looking at. Maybe the impact on Jupiter need resurrecting, although I understand it is referred to as the Solar Systems vacuum cleaner. So I do not think scientists will say we are immune from anything. Anyone?

Re life being wiped out. No it hasn't, you are living proof. That is not to say that humans will survive or indeed anything. Depends on the mis hap.

PS. If the Earth makes it then I understand the current theory is the sun will eat us all up. We will need the scientists to get off this rock before that happens. Hurry up, several billion years left.