In our search for alien life we can receive only one of two answers. Either we are someday able to find and communicate with another civilization or we unearth only more and more silence, many of us trying to remain hopeful in its stony presence. We receive a signal, or we don’t; either way we come to an important realization about our place in the universe. Not many of us want to believe — and not many of us do believe — that we are alone. To think that humans are so special embodies an air of arrogance and pride. Neither is it statistically supported given the bounty of star systems and habitable planets dangling in the data from our telescopes. And yet despite those great odds in favor of alien life, we remain empty-handed.
The word itself — alone — has a negative sensation. We do not want to be alone on any level, whether it be individual or as a species. But it may not be such a desolate truth to face. On the contrary, being alone could mean something remarkable for our future.
Finding another civilization out there in that velvety dark would mean that life on Earth was not so special as we’d thought. That is the advantage — a promise that we are not commonplace. And this promise is at the heart of ‘Fact A’: there are no intelligent beings from outer space on Earth now. Because they are not here then they do not exist. It is a simple observation named by astrophysicist Michael Hart in his paper from 1974. If intelligent beings were alive and bustling in our galaxy or any other, Fact A would not be our reality.
The fact is an argument against every explanation for the Fermi paradox (there are great odds aliens exist, yet why haven’t we heard from them?).
The most straightforward of these answers to the Fermi paradox is physical challenges. Interstellar travel is difficult but not impossible. We have already accomplished the feat with two separate spacecraft (Voyager 1 and Voyager 2), and while travel to another star system is more complicated than travel to the moon, they are essentially the same problems on different scales. Aliens — which may not be warm-blooded nor have lifespans as short as ours — can use suspended animation or freezing temperatures to preserve passengers on their long trips. Robots can captain a ship until arriving at its destination, whereupon frozen zygotes can create a new population of life on the foreign planet. Any craft undergoing interstellar travel will have to move away from chemical energy and into more efficient means, such as nuclear energy. As an example, a ship able to convert only .33% of its nuclear energy into kinetic energy will have to carry nine times its own weight in fuel. This ratio of fuel to payload can be reduced by traveling at slightly slower speeds or perhaps refueling using hydrogen atoms from the interstellar medium.
With our current technology and physics, colonizing the galaxy would take a mere 10 million years. The question is why no alien civilization has yet to undertake this kind of widespread growth.
When it comes to sociological concerns — such as spiritual and political beliefs — there is one main flaw to all the hypotheses. They cannot apply to every race of extraterrestrials and they cannot hold true throughout all the years of that civilization’s history. With each new generation of mankind comes new revolutions in thinking, in morals, upheavals of our past ideals in order to move forward. It is true that the Self-destruction Hypothesis may apply to some advanced civilizations. We see it creeping up in our own society as Earth bears extreme weather and the weight of our nuclear arsenal. But even if most alien life did destroy itself or chose not to explore the universe for cultural reasons, this assumption can’t hold true for every single race of alien life.
Using ourselves as an example, we see that life is as flourishing as it is self-destructive. It sprawls into the most unexpected areas, unfurling in unlit caverns and churning in the stifling, fervent vents of the ocean floor. For every civilization that self-destructed there would be another civilization pouring itself out across the star systems. In order to endure, a civilization must be as wise as it is intelligent.
The idea that aliens have not had enough time to reach us is also unlikely. If there were no breaks between voyages, colonies started today could expand exponentially and pervade the majority of the Milky Way within 650,000 years. Only if a civilization became space-faring less than 2 million years ago could we say that they haven’t had enough time to arrive on Earth. Except, the Milky Way is one of the oldest galaxies at 13.5 billion years old. For a space-faring civilization to arise less than 2 million years ago and for us to then evolve so shortly after that is a great coincidence. It means that for over 13 billion years there were no signs of advanced life, but then suddenly two separate instances occurred within a couple million years of each other.
The last main explanation for the Fermi paradox is really a refutal of Fact A: aliens are here, but we have not recognized them. And perhaps there is a pearl of wisdom in this. How would we recognize alien life? It may be so strange to us that we may not see it as life at all. But this conflicts with the ever successful Occam’s Razor, a principle of science which reminds us that explanations should be as simple as possible and only when all the simple solutions fail can more complex ones be invoked. To say that UFOs are the result of alien activity is to forget Occam’s Razor — there is no UFO evidence to date that cannot be explained by natural or manmade causes.
Case IV is a — perhaps — bleak relative of Fact A. Suggested by radio astronomer and mathematician Ronald Bracewell, Case IV says that we are alone because if it were nature’s plan to create intelligence and have it diffuse across the cosmos, it need only succeed once. As per what has happened on our own home. The plan to spread intelligence did not depend on it developing across several species or several points in time or along several locations on the face of our grainy, textured planet. To succeed, it only had to do it well and do it once. From our ape beginnings came mankind, ambling out of the ruddy bushes and sunsets of Africa to explore and dominate even the coldest and most remote reaches of our landscape. It’s a model that’s as efficient as it is isolating. In terms of creating a galactic colony, our species could attain the heart of the Milky Way much faster than the four billion years it took for Earth to create mankind. There is no need for organisms to arise in any other place in the universe.
So then our search will be fruitless.
To accept Fact A or Case IV is to say that we are alone and have always been alone. But this is not a remark made out of arrogance, or pride. Nor is it one that’s necessarily as pessimistic as it may at first seem. As unpopular as the opinion is, admitting that we are alone in the vast, vast amazon of the cosmos presents us with a solitude, but perhaps also with the invaluable destiny of spreading the first roots of life and consciousness far beyond our home. It confirms the importance of our civilization — our descendants will inherit the fire, the toil, the fertile garden of the star systems.
Some way through the epic of Interstellar there is a line that sums up our purpose — if this is our purpose — in a single, resounding quote. “Our greatest accomplishments cannot be behind us, because our destiny lies above us.”