In the larger scheme of things, where are all the aliens if Earth is so unremarkable? To answer the question, a group of experts from NASA’s Jet Propulsion Laboratory examined the Great Filter idea, humanity’s role within it, and our species’ destiny.
In what they refer to as the “most unsettling solution to Fermi’s Paradox,” they warn in the article that the filter “has the potential to eradicate life as we know it, especially as our rate of progress correlates directly to the severity of our fall.”
The Fermi Paradox may be familiar to you, but in case it hasn’t, let me briefly explain: Since Earth is not the only planet in the cosmos, there is a good chance that alien life exists elsewhere. So why hasn’t anyone made contact? Why aren’t they doing what we are, sending out probes and frantically looking for other signs of life, if there are so many other civilizations out there, possibly at far more advanced stages than we are because of how long the universe has dragged on for (no offense, universe, but get to the point)?
The Great Filter is one potential remedy. According to the theory, something has to happen to stop extraterrestrial civilizations from leaving their star system and starting to colonize their galaxy or maybe the entire universe before they can reach the stage where they can do so, or else we would see evidence of this in the Milky Way. We just don’t know if this is the transition from multicellular life to animals with the ability to utilize tools, or if it is simply our current state to galactic exploration.
We wouldn’t know if we have passed the “great filter” or if it would occur in the future, which is what makes this so intriguing. Is it possible that while most only survive to be single cells, we have already surpassed this filter? Or are we, like past extraterrestrial societies, going to end ourselves before we can leave Earth at some unspecified period in the future—possibly by a conflict or depleting our resources before we can flee?
The team argues in their paper that for us to successfully pass this “great filter” and evolve into an interstellar species, we must first take the time to reflect on where we are and the apocalyptic threats we face, such as massive nuclear war, naturally occurring and artificially created infections, artificial intelligence (AI), impacts from asteroids, and climate change. To pass the great filter—assuming it is still ahead of us and other alien species don’t go extinct before they have reached it—the article lists the risks that each presently poses as well as the steps that would need to be taken to overcome them.
Regarding the nuclear threat, which they describe as “perhaps the most obvious of Great Filters,” the team is quite upbeat. They point to longer patterns of a tendency away from conflict (albeit they claim we are still caught in a “vicious circle”) and towards democracy and peace, albeit imperfectly. Asteroids are also thought of as a filter that technology can get past. Take the recent DART mission, for example, in which NASA slammed an asteroid into it to divert it.
“Prudence then strongly suggests we perform sooner rather than later what modeling can be done, evaluate the necessarily preliminary conclusions drawn and proactively plan for a peaceful approach to the possibility of sharing the Earth with a new technological entity.”
In the end, the team feels that mankind needs to commit to more long-term thinking to overcome these significant barriers to passing whatever filters are ahead of us. A component of this would be resolving to pursue the objective of developing into a Type 1 civilization, capable of utilizing all the energy that our host star provides for our planet.
“Setting our sights on becoming Kardashev Type I civilization, perhaps achievable in little more than the time taken to go from first practical steam-driven engines to the present, would be ‘giant leap for humankind’ in the right direction,” they say.
“Attainment of Type I status would all but assure any Great Filter has been successfully overcome, unfolding an all but unlimited future for humanity.”
To sum up, the team believes that progressing past Type 1 civilization is also feasible.
“To prepare for our journey, we can likely count on the inner Solar System remaining habitable for another few billion years until the Sun begins to expand towards red giant status,” they state. “Time enough for humanity to finally make other stars our home.”