Have you ever looked up at the stars and wondered how many aliens are out there? The great scientist Enrico Fermi wondered the same thing in 1950. Some basic calculations show that there should be as many planets with life as grains of sand on Earth. The question is: if there should be so many aliens, why haven’t we heard from them? This became known as the Fermi Paradox.
The great filter is a possible solution to the Fermi Paradox. It is the theory that once a civilization gets too advanced for its own good, something horrible happens that destroys that civilization. There are many possible filters. For example every time a civilization gets too advanced:
- It changes its environment so mucuh that it destroys itself, such as through runaway climate change.
- It creates advanced weapons and destroys itself, for example with nuclear weapons, biologoical weapons, or nanoweapons.
- An advanced alien race monitors the universe for competition. As soon as a civilization becomes too advanced, the aliens destory or enslave it.
If there is a great filter, we can only hope that we’ve already passed it. For example, we have survived an entire 50+ years since the invention of nuclear weapons. However, we know for certain that there are several possible filters in our future such as climate change, large asteroid impacts, or any number of new weapons of mass destruction that we will create through technology. We best be ready to fight them!