Alien civilizations may have slowly wiped themselves out, or been wiped out by climatic catastrophes on their own planets. In a new document published on the ArXiv pre-press web server (I link it here), a group of NASA scientists analyzed the “Great Filter” theory, which postulates that ancient alien civilizations may have wiped themselves out before making contact with us. This would explain why we are currently alone in the universe.
The new workshop serves as a warning, and paints the picture of a universe that has been home to many civilizations, few of which long-lived enough to become interplanetary species.
Does climate change solve the Fermi paradox?
The “Great Filter” theory offers perspective on how entire civilizations may have slowly created the conditions that led to their own demise. And it is, to all intents and purposes, also a possible answer not incompatible with the Fermi Paradox (if the alien life intelligent is abundant and widespread, where is everyone? If we are not alone, why do we seem so?).
Let's say, the researchers reflect, that an existential disaster hits us head-on as our society advances towards space exploration. We would be wiped out before we could encounter another civilization. And this may have happened to other civilizations too, everywhere. More generally, many civilizations over millions of years, throughout the universe, have already faced every existential threat we face on Earth (nuclear wars, pandemics and more) and to which we could succumb.
The Great Filter explains why we are alone
The Great Filter theory was first proposed in 1998 by Robin Hanson, an economist at George Mason University. In an essay at the time, Hanson wrote that "the fact that our universe appears dead suggests that advanced, explosive, long-lasting life is very, very unlikely to arise." Hanson suggested that many alien civilizations may have evolved to a point before they had the technology needed to expand off-world, only to have then been wiped out. I gloss over the optimism (which, moreover, would be unjustified these days).
In their new paper, NASA scientists say that evolution is imperative to not succumb to the “Great Filter.” “History has shown that intra-species competition, and more importantly, collaboration, has led us to the highest heights of invention,” the paper reads, “Yet, we prolong notions that appear to be the antithesis of long-term sustainable growth. Racism, genocide, inequity and more."
There are those who say no
Some scientists reject the Great Filter theory because it does not take into account our current limited ability to see the cosmos. After all, as astronomer Seth Shostak of the SETI Institute says, “we're just starting to look.” Any theory that starts from an assumption like “we are alone” is premature to say the least.
Of course, if we consider the new study as a warning, and as a confirmation that only human collaboration can save our lives, its conclusions must be fully embraced. We are truly alone, in other words, only if we don't help ourselves. We are only truly alone, to quote Quasimodo, if "in the heart of the earth" everyone is alone.
