Why have we not discovered intergalactic alien life yet?
Enrico Fermi posited that a series of events need to occur for such advanced civilizations to emerge. Life must exist, Life must evolve to sufficiently complex organisms without going extinct, those complex organisms must form a civilization, that civilization must become sufficiently complex without going extinct, and so on.
When we multiply the products of these probabilities, we get the probability of any given planet having a civilization of that threshold level of complexity. There is an astronomically large number of planets in the universe, yet we have not encountered any extraterrestrial life, raising the possibility that perhaps one of these probabilities is a pinch point in the ascent of civilizations.
Here we sit, chatting on the internet as a civilization of hominids that spans the globe and has advanced technology capable of sending signals to the stars. Yet, there is no indisputable evidence of extraterrestrial life, and so while we wait for reassurance that civilizations can be made sustainable with high probability, it’s worth evaluating our own world for possible weaknesses.
Nuclear weapons seem like one such weakness. After we advanced science to the point of splitting atoms and releasing extremely large amounts of energy in nuclear reactions, our world of primates did what primates tend to do: we made weapons. We hominids are notoriously tribal – it’s a blessing and a curse. Tribalism is a blessing as our tribalism helped us form groups that formed societies, but it is also a curse in that at some level we inevitably seek differences, draw lines in the continental or social sand, and succumb to our proclivity towards distrusting people on the other side of the line. Countries developed nuclear weapons and pointed them at each other in an act of deterrence, letting other countries know of their mutually assured destruction in the event somebody crosses the wrong line.
Nuclear weapons have been around for a brief 80 years, and thankfully we seem to understand their consequences well enough to be sufficiently deterred from using them. These remain a significant threat to human civilization, but it’s possible they are not the answer to the Fermi paradox.
Another possible answer is less operatic, more tragic: disease.
Hellbound and Down 