8 Insane Doomsday Predictions That (Unsurprisingly) Didn't Happen

Bonus: The Grey Goo Hypothesis

This is not a doomsday prediction from the past, but one for the future, and it has nothing to do with the Second Coming or rogue asteroids or even a good robot uprising. Sort of.

The Grey Goo hypothesis refers to an accidental apocalypse brought about by self-replicating robots and some careless coding. If a swarm of simple nanobots were given the ability to self-replicate using materials from their surroundings, then they could hypothetically consume the Earth and everyone on it in a matter of hours.

The number of nanobots would grow exponentially, and if we run the numbers based on the assumption that it takes a nanobot a minute to replicate itself, after an hour and you get something like 1.15x10^18 (1152921504606846976) little bots scuttling around. In a day, you get 3x10^433, but you wouldn't need to worry about that as, if we assume they weighed just 1 nanogram each, their mass would be sufficient to collapse into a black hole-like object after 161 minutes.

So, forget a super-AI pressing the human race into subservience, the robotic apocalypse could come from the small yet mighty nanobot.