This post is largely a response to one of my favorite articles ever written about any topic, period. The Fermi Paradox, from Wait But Why, does a fantastic job of explaining the paradox itself, as well as a number of plausible explanations to the question we all want answered: “Where is everybody?” I’m commenting on a few of my favorite sections as well as including some of my own insights and analyses… because… I love this stuff!
What is the Fermi Paradox? Named after Enrico Fermi, Italian physicist and inventor of the first nuclear reactor, the Fermi Paradox is the apparent contradiction between the lack of evidence and the high probability estimates of the existence of alien civilizations. In 1950, Fermi reasoned that there are likely billions of stars in our galaxy similar to our sun, and, with high probability, many of these stars would have Earth-like planets. Given the relative youth of our sun when compared to other stars in the galaxy, Fermi believed that if Earth is “typical”, it should have already been visited by extraterrestrial civilizations exploring or colonizing the galaxy.
Nearly seventy years ago, Fermi developed his hypothesis with only a fraction of the information we have today. The first exoplanet (planet outside of our solar system) was not confirmed until 1992, and since then, thousands of planets have been found orbiting stars other than our sun. In 1950, Fermi could have never grasped how truly common planets actually are in our universe. To further frame Fermi’s paradox, let’s use some conservative estimated numbers taken from Wait But Why:
*Speculation*
- There are between 1022 and 1024 total stars in the universe, which means that for every grain of sand on Earth, there are 10,000 stars
- There are ~500 quintillion sun-like stars
*More speculation*
- There are ~100 billion billion Earth-like planets, which means that for every grain of sand on Earth, there are 100 Earth-like planets
*Now time for wild speculation, but we’ve gotta do it*
- There could be ~10 quadrillion intelligent civilizations in the universe
- There could be ~1 billion Earth-like planets and ~100,000 intelligent civilizations in our galaxy alone
Wow! Can anyone wrap their head around that?! I sure can’t, and it’s kept me up at night trying. Again, these are estimates, not facts, based on available data today, but it really puts into perspective what could be out there. So as Fermi said… where is everybody?? Wait But Why attempts to assign possible answers into two explanation groups.
Explanation Group 1 says that there actually are no higher civilizations in existence – reason being: we’re either “rare, first, or fucked.” The gist behind this logic is that at some point in the timeline of any species’ development there is a “Great Filter” that somehow prevents a species from continuing on its evolutionary track. If this were true (and, spoiler alert, I subscribe to Explanation Group 2), the million-dollar question would of course be: at what point in a species’ evolutionary timeline does the Great Filter occur? …wouldn’t that be nice to know?!
I generally refute all of these hypotheses, and here’s why:
We’re rare: the sheer size of the universe, as indicated by the data above, should at least cast some doubt on the idea of scarcity of life. That said, if the Great Filter exists and we’re already past it, what was it that other species and civilizations couldn’t overcome? What is it about the conditions on Earth or its inhabitants that have made us so special in the vastness of space? No one knows how life actually began on Earth, so how can we confidently predict how it would begin on another planet under different circumstances? We’re aware of the known building blocks for life on Earth (elements such as oxygen, hydrogen, carbon, nitrogen, sulphur, and phosphorus – and some kind of energy source) and can confirm that they are abundant in our universe, but that doesn’t mean that it’s the only recipe for producing life as we know it (single-celled organisms that evolved into intelligent beings over time). Sure, evolution has been “proven” because it’s observable and measurable, but that doesn’t necessarily mean that human beings are purely the product of random mutations and natural selection over ~3.8 billion years. I believe it’s probable that forms of life can emerge and evolve from more than one type of beginning, and that our definition of life is pigeonholed into our narrow understanding of the contents and processes of the universe we live in. Consider the “infinite hallway” thought experiment. Imagine you’re standing in a long hallway where you can’t see far enough in either direction to determine where you came from or where you’re going. Suddenly you hear and see a ball bouncing towards you from behind – the ball approaches, bounces past you, and disappears into the distance of the hallway. The ball is real of course, you were able to witness it as it approached and passed you by. But where did it come from? What made it start bouncing and allows it to continue bouncing? Where is it going? These are basic questions that can also be applied to the concept of the evolution of our species, and any species for that matter – because, frankly, no one knows the answers to arguably the most fundamental problems with describing our origin. I contest the fact that we’re rare because there is a hell of a lot of space out there filled with the elements believed to support just one version of the creation of life. If we’re rare…talk about the ultimate waste of space.
We’re first: if we’re not rare, we’re not first. The universe is ~13.8 billion years old, and it’s estimated that stars started forming just 200 million years after the Big Bang. I’m not saying there could be civilizations out there that are nearly as old as the universe itself; there still had to be a significant cooling period to allow for the gas cloud from which a sun is formed to supply enough heavy elements to coalesce and create rocky and gaseous planets. However, our star is only ~4.5 billion years old – a mere young adult in the universal society! Once life has formed, there is a compounding effect on an evolving civilization. Think about how quickly humans have evolved in the last ~century. Prior to December 17, 1903, when Orville and Wilbur Wright made history in Kitty Hawk, North Carolina by piloting an aircraft for just 12 seconds covering 120 feet, human beings hadn’t yet left the ground. Just 66 years later (1969), man walked on the moon, and 43 years after the moon landing (2012), Voyager 1 left our solar system and is currently traveling in interstellar space! Our knowledge about physics, aerodynamics, and engineering – among many other things – has drastically improved in a very, very short period of time when you’re looking at the galactic calendar. If we’re first, that would imply an unfathomable number of significantly older and potentially habitable rocky planets in the Goldilocks Zone that for some reason, couldn’t support life. Seems like a stretch.
We’re fucked: this one is tough, but as an optimist, I can’t accept the possibility that humanity is unknowingly staring ahead at our eventual demise and would not be able to survive the crisis of a self-inflicted Armageddon. If the Great Filter exists and is some form of environmental disaster or technological anarchy, I believe that humans would adapt and overcome. When faced with dire adversity, our species would have a remarkable ability to defy probability and survive. The end of days via an external threat, such as an asteroid or solar flare, would imply too much randomness involved for some Great Filter to exist as a constant being applied to all civilizations in existence. If the Great Filter exists, is non-random and predetermined, and is completely out of our control… then ya… I suppose we’re probably fucked.
OK – now on to the good stuff!
Explanation Group 2 says that higher civilizations do exist, and there is a logical reason why we haven’t been contacted yet. Those who subscribe to Group 2 (like me!) believe we’re not rare, first, or fucked, but rather “mediocre” and that our type of planet and intelligence is actually common in the universe. Wait But Why provides ten possibilities for why we’ve not been contacted. They are:
- Super-intelligent life could very well have already visited Earth, but before we were here
- The galaxy has been colonized, but we just live in some desolate rural area of the galaxy
- The entire concept of physical colonization is a hilariously backward concept to a more advanced species
- There are scary predator civilizations out there, and most intelligent life knows better than to broadcast any outgoing signals and advertise their location
- There’s only one instance of higher-intelligent life – a “superpredator” civilization – that is far more advanced than everyone else and keeps it that way by exterminating any intelligent civilization once they get past a certain level
- There’s plenty of activity and noise out there, but our technology is too primitive and we’re listening for the wrong things
- We are receiving contact from other intelligent life, but the government is hiding it
- Higher civilizations are aware of us and observing us
- Higher civilizations are here, all around us. But we’re too primitive to perceive them
- We’re completely wrong about our reality
While most of these are plausible possibilities (and all are interesting to consider), I have four favorites I chose for more thorough analysis.
(1 & 8) I’m going to cheat a little bit and combine two possibilities into one, because they go hand-in-hand, and it’s my blog so I can do whatever I want. It’s reasonable to believe that Earth has been visited in the past by higher civilizations exploring the galaxy, but humans either weren’t here yet, or it was too long ago for any written documentation to have been produced to tell future generations of the experience. As a result, higher civilizations are aware of our planet, and are keeping tabs on us, but have chosen to not interfere with our individual evolution, either because of some intergalactic law or for informational purposes to witness a natural societal progression. The earliest form of written language is debated to be either the Sumerian archaic (pre-cuneiform) writing or the Egyptian hieroglyphs, produced sometime between 3400-3100 BC. What if a higher civilization visited Earth just 6,000 years ago? There would have been no way to document it! The earliest fossils of anatomically modern humans date back about 200,000 years, so early humans could have witnessed multiple alien encounters but we’d have no way of knowing about it today.
Additionally, any number of higher civilizations could be continuously watching us from a comfortable distance without making us aware, whether they’ve visited Earth or not. Though we’ve only been broadcasting radio signals into space for ~120 years, long-range scans of our atmospheric makeup using sophisticated technology from an advanced species would have at least tipped them off to the possibility of a planet ripe with the elements necessary to support organic life. If so, we’re on their radar, but presently, we pose no threat to anyone other than ourselves and our planet, so why should a high civilization need to reveal their existence? One might fear that a hostile civilization watching us would eventually reveal themselves to acquire some of our natural resources, but I think that any higher civilization sophisticated enough to traverse interstellar space would not be hostile. Why, you ask? Because it’s rational to hypothesize that any species advanced enough to have mastered the fundamental and quantum laws of the universe would be innately logical and civil in nature, and not hell-bent on destruction. If hostility and violence were a primary part of their DNA, they’d likely destroy themselves before they could ever leave their own planet. I believe (and hope) any high civilization that drops by Earth would simply be explorers of the great abyss.
(6) What if there actually IS a lot of noise going on out there, but our technology can’t detect it or we’re just searching for the wrong things? That would be a huge bummer (a technical term), but it’s certainly possible. The Search for Extraterrestrial Intelligence (SETI) is an organization set up in an effort to detect evidence of technological civilizations that may exist elsewhere in the universe, particularly in our galaxy. Most SETI searches focus on radio signals, and most of these hunt for narrow-band signals, radio emissions that cover only a small portion of the radio spectrum. Natural objects in space blanket the spectrum with signals, so finding a signal that only dominated a small region would be suggestive of an artificial source. Despite these ongoing searches, no proven artificial signal has even been detected. Perhaps the most famous possible alien signal ever detected from deep space is the “Wow! Signal”, a mysterious and strong narrow-band radio signal received on August 15, 1977, by Ohio State University’s Big Ear radio telescope. Physicists have long speculated than an advanced civilization attempting to make contact via radio signals may do so by broadcasting at a frequency of 1420 megahertz, which is naturally emitted by hydrogen, the most common element in the universe and, therefore, likely familiar to all technologically advanced civilizations due to its abundance. The entire duration of the “Wow! Signal” lasted for 72 seconds, and was received at two different frequencies: 1420.36 and 1420.46 MHz. The astronomer making the discovery was so shocked and excited about the printout that he wrote “Wow!” in the margin next to the data (thus the name). The signal appeared to have originated from the constellation Sagittarius, however, every attempt to detect the signal again has been unsuccessful.
SETI’s search for narrow-band radio signals attempting to detect alien civilizations is certainly a logical approach, in theory, given what we know about the universe. However, consider this: scientists have no idea what 95% of the matter-energy in our universe consists of, because it has not yet been observed. How is it possible that we can’t detect or directly measure the content of 95% of the mass-energy in our universe?!? If I knew I’d tell you, but no one knows! The most accurate measurements to date reveal that of all the mass-energy in the universe, 68% is made up of dark energy, 27% is made up of dark matter, and only 5% is made up of regular matter! Dark energy can be described as an unknown energy that is accelerating the expansion of the universe, whereas Dark Matter can be described as an unknown matter that doesn’t emit light or energy, yet somehow holds the majority of the elements of the universe together… but unfortunately, that’s the best we’ve got. Knowing the fact that we can only reconcile 5% of the matter-energy in the universe, it’s reasonable to assume that more sophisticated civilizations have a better understanding of these strange properties and are using them to harness technology used for communication, travel, and sadly, many other things that we humans cannot yet hear, see, or even comprehend. It’s possible the truth is out there, in plain sight, and we’re just oblivious.
(10) This one is the dark horse, but hear me out. Maybe we’re completely wrong about our own reality. In 1999, I saw the movie “The Matrix” and thought it was amazing, but obviously a fictional concept. Now… I’m not so sure. The notion that our entire reality could be a computer simulation created and administered by an advanced civilization can’t be dismissed. Why? Technological advancements in artificial intelligence, machine learning, and virtual and augmented reality in just the last ten years indicate that creating a simulation that is indistinguishable from reality is not only possible, but rather even likely to occur in the coming decades. Imagine what a civilization with a couple billion-year head start could create? This is just an observation from witnessing our own rapid technological evolution. How about more subtle clues? When you look around, the same numbers and equations tend to show up again and again in explanations for how objects move around points in the universe: Pi, the speed of light, Planck’s constant, the gravitational constant… and the list goes on. What about the generosity of the periodic table? Take hydrogen and oxygen, for example – one is an explosive gas, the other promotes violent combustion – yet combined, they make liquid water, which accounts for >70% of our planet and is fundamental to human life. Doesn’t that sound a bit convenient? I’m not a quantum physicist (surprise!), but what about the measurement problem paradox? What about the fact that when we try to view subatomic particles, things just get “fuzzy”, and no one knows why, however, their behavior is governed by certain rules, and those rules are very similar to the codes that run web browsers and search engines?? That’s wild! Those who oppose this theory would likely point to free will, the ability to choose between different possible courses of action unimpeded… but couldn’t our perception of “free will” just be nothing more than a string of unbelievably advanced polymorphic code or a mutating algorithm? It’s not THAT crazy. Maybe no other civilization has made contact yet because it’s been programmed that way.
If we’re not living in a simulation, what if our universe is just one universe that exists in parallel, and all of our choices are actually played out in alternate realities in the landscape of a grander multiverse? Sounds extreme, but the Big Bang as a singular event doesn’t make mathematical sense. Neil deGrasse Tyson and Brian Greene have suggested that the math shows you don’t use up all the fuel in a single Big Bang. In fact, the bang itself winds up generating more of the fuel which generates other bangs and other universes. Additionally, scientists measure the size of the universe by using a number of different tools such as trigonometry, parallax, standard candles, supernovae brightness, galactic red shift, and the cosmic microwave background. In doing so, they’ve discovered a mysterious “Cold Spot” about 1.8 billion light-years across. It’s cooler than its surroundings by around 0.00015 degrees Celsius, and technically shouldn’t exist. Some evidence suggests that this cold spot could be proof of the existence of a multiverse – the collision of our universe with that of a neighboring universe. Perhaps we’re rare to only our universe… but infinite other civilizations exist within their own specific universe. Chew on that.
If you stayed with me the entire time, that was a lot to digest, but I hope to have at least provided some food for thought. Earth is just a Pale Blue Dot in a vast cosmic arena – a mote of dust, suspended in a sunbeam. Are we alone? I don’t think so, but I don’t know. Either way, the answer would be deeply humbling. My only wish is that humanity continues to wonder and search for the answer to Fermi’s question…
”Where is everybody?”