Sitting in Los Alamos National Lab, physicist Enrico Fermi looks up from his lunch break and asks his colleagues a question that has been debated ever since.
“Where is everybody?”
From sci-fi blockbusters to the recent Area 51 raid endeavors, extraterrestrial life has caught the attention of children and physicists alike. I’m sure that almost everyone, at some point, has gazed into the star-studded sky and wondered: is anyone else out there?
While I cherish my childhood memories of the Toy Story martians and the oddly shaped Jar Jar Binks from Star Wars, the physics behind the topic itself is even more intriguing. Here, I’ll offer my human insight on this alien problem and try to convince you of two things. First, that other intelligent life forms exist in abundance nearby, even in our own Milky Way galaxy; second, that the reason why we haven’t received signals of other life is due to our own lack of intelligence and technology.
Let’s start where just about every physics lesson begins: with an equation.
Formulated in 1961 by astrophysicist Frank Drake, the Drake Equation offers a prediction on the number of advanced civilizations in a given area. In layman’s terms, this equation is essentially an alien population predictor. With some data points with stars, planets, and percentages, Drake calculated between 1,000 and 100,000,000 other intelligent beings in our galaxy. Math doesn’t lie, and our question appears to have been answered.
Where is everyone? Simple: all around us.
But that’s not satisfying, is it? For one, if these calculations predict so many other intelligent life forms around us, why have we not seen signals of contact from them? This is where Enrico Fermi’s lunchtime speculation comes back to the forefront of discussion. His infamous question, now formally known as the Fermi Paradox, is, to this day, completely unsolved. However, I would like to consider four different hypotheses and unpack both their viability and the implications they provide to humanity as a species.
(Above is a video explaining the basic concepts regarding the Fermi Paradox, as well as a brief introduction to the solutions discussed below.)
The first potential solution has been coined the Zoo Hypothesis, with the explanation being just that: we are like animals in a zoo. Humans do this all the time. From zoo exhibits to national parks and reservations, we often observe less intelligent animals in their natural habitats and avoid interfering with their ecosystems. Replace a zebra or panda with humanity and the bars and cages with a galaxy, and you have yourself a fascinating perspective of our universe and those watching from the outside—Exhibit Earth of the Galactic Zoo: the human species. I wonder how much the entrance fee would be to see the 2020 elections pan out.
But we don’t always leave other animals alone, and this philosophy allows us to arrive at a more humbling solution to the Fermi Paradox: we’re just too stupid to hear alien signals. To put this into perspective, imagine being stranded in a desert all alone. After billions of years of wandering, you come into contact with another species—a desert ant. Isolated and lonely, you try desperately to have it acknowledge your existence. You tell it stories, sing it songs, and write it letters. Will the ant ever realize that there’s a much smarter animal attempting to make contact with it? Of course not—some species are comparatively more advanced than others, making communication between the two impossible. But that’s just it.
Another well-known hypothesis is the Great Filter. At a basic level, it states that there are multiple steps for species to be complex enough to harbor galactic communication, and that we are one step away from doing so. I, as do many theoretical physicists, find this near impossible to believe. Consider the Earth alone, with around nine million plant and animal species. While we may reign supreme on our home turf, the probability for our superiority at the predicted scale of around one hundred million species seems far-fetched, at best.
A more eerie rendition of the Great Filter takes us to our last solution: intelligent beings self destruct. Whether it be from overpopulation, pollution, or unsustainable environmental practices, the energy and resources required to maintain a complex, technological society are extremely taxing. Perhaps species, before gaining the ability to communicate intergalactically, destroyed themselves. They ignored their planet’s atmosphere and exploited natural resources, leading to their gradual, yet inevitable, extinction. Sound familiar? It should—it tells the horror story of our current battle against climate change and carbon emissions near perfectly.
While these hypotheses remain speculative in nature, a common truth seems to arise no matter which angle you attack the problem from—we are not nearly as smart as we think we are. Regardless if it be through a lack of technology and resources or the overuse of it, humanity as a whole remains oblivious to the world around them both domestically and in the Milky Way. To answer the question, “where is everybody?”, perhaps it’s best to first look retrospectively at ourselves rather than the cosmos above.
Works Cited
“Drake Equation.” Drake Equation, SETI Institute, www.seti.org/drake-equation-index.
Jasty, Kunal. “6 Mind-Bending Solutions to the Fermi Paradox.” Medium, Radio Open Source, 30 July 2014, medium.com/tag/astronomy/archive.
Kurzgesagt. “The Fermi Paradox – Where Are All The Aliens?” YouTube, YouTube, 6 May 2015, www.youtube.com/watch?v=sNhhvQGsMEc.
Shostak, Seth. “Fermi Paradox.” SETI Institute, 19 Apr. 2018, www.seti.org/seti-institute/project/fermi-paradox.
Woah! I really love how you tacked a topic that was truly unique yet interesting at the same time. In my opinion, space travel and extraterrestrial life are some of the most fascinating topics to learn about and I feel like you captured that curiosity and joy amazingly. However, I do feel like you could have expanded on the idea of the great filter more as you seem to kind of glance over it. Furthermore, the great filter captures more than the idea of self-destruction. From my understanding, the great filter also encompasses the barriers living organisms face when becoming life forms and or achieving intelligence which also could have been emphasized (and which also would have brought evidence contradict the Drake Equation). However, I really loved how conversational and funny entire piece was and it really helped bring life to a more obscure topic!
Okay, I completely follow what you’re saying, but I have a couple questions; forgive me if the science is completely wrong on these.
What if there are similarly-intelligent beings like ourselves around us, that haven’t self-destructed, but just haven’t figured out a way to traverse the universe, or, at least, traverse the universe in a way that intersects with Earth? After all, isn’t the cosmos supremely vast? Even if a species elsewhere in the Milky Way figured out how to travel quickly throughout space, what’s stopping them from hopping over to the nearest galaxy than exploring us? Isn’t a plausible explanation to the paradox that, simply put, the universe is just too big and we’ve existed for way too small a time frame to notice anything? That there are beings that didn’t self-destruct, aren’t watching us in a zoo, and have passed the Great Filter but just haven’t hit us yet?
I hope we someday find out, although I fear humanity may be putting itself on its own irreversible path (climate change, anyone?).
This is another commonly discussed hypothesis, however there are a few assumptions made here that are just frankly incorrect. First, the Milky Way galaxy is not nearly as vast as you would think. While it is true that we are only a tiny dot in a whole canvas full of stars and planets, the video linked in the post cites calculations stating that the a more advanced civilization capable of traveling between stars could easily colonize the galaxy within 2 million years. Now, while humans have not even existed for that long, the Universe itself is around 13.8 billion years old. This means that, under the probably assumption that our species is not special, and considering that homo sapiens (humans) have only been around for a mere 200,000 years, the probability that a civilization reaches this level of traveling technology is almost inevitable.
It is true that we have only existed for a small time period. Yet, we can still peer into the past to the beginnings of the universe. Take the Cosmological Microwave Background, oscillations and perturbations from the very beginnings of our universe. Even fossils in the Earth can date back to hundreds of millions of years ago, which provides us “signs of life” on Earth. However, no “fossils” have been found when looking out from Earth, and the reason of this mystery can be contemplated using the hypotheses in the post I have made.
Hey Jason, I love your choice of topic on this blog post! Just this summer at a Stanford summer camp my class spent an afternoon discussing the implications of Drake’s equations in an astrochemical context. During that discussion, we each calculated our own set of hypothetical upper and lower bounds to Drake’s equation, and though we each produced wildly varying results, we found that they were around similar orders of magnitude to Drake’s estimates: a quite low minimum relative to a quite high maximum. But we took these estimates at face value. Given the vast expanse of the universe, with trillions of planets, astronomers would have to do an insane amount of guessing and checking to find any signs of life. I think it’s great that beyond this probability analysis, you brought into view three theoretical explanations to Fermi’s question. I thoroughly enjoyed reading them; your post was very educational. That said, if we follow Fermi’s Paradox, over what scale of time do you think humans would need to exist to develop technology advanced enough to communicate with intelligent extraterrestrial life?
Hi Kevin, thanks for the questions and feedback!
To answer your question, I’d argue that we easily have the technology advanced enough to communicate with other life forms. The Search for Extraterrestrial Intelligence (SETI) already has sent multiple signals using concepts like math, basic physics, pictures, and electromagnetic radiation in an attempt to hear back, but nothing has been heard since the creation of the organization itself.
In a more nuanced argument, Fermi’s Paradox also make a lot of assumptions, namely that there are many types of civilizations in what’s known as the Kardashev Scale. Type I is the ability to harness the energy that arrives on their planet. For us, that would mean being nearly 100% efficient with all solar and wind energy, fossil fuels, etc., which estimates calculate that humanity is nearly 70% or so to being Type I. However, Type III, the ability to harness all of the energy in your entire solar system (including the stars and planets around you) is the hypothesized level of “advanced”-ness to be able to easily navigate one’s way around their galaxy. Since we have no evidence of any civilization more advanced than us, it is impossible to predict when, or if, this will be achieved.