Where Are All The Aliens?

March 6, 2022. By Hadrian Barki '23

With mind-boggling numbers of habitable planets and billions of years before us, why don’t we have any evidence of precursors before us or even other intelligent life? Where are all the aliens?

With so many stars in the Milky Way Galaxy and God-knows-how-many galaxies in our universe, there has to be some form of technologically advanced life out there other than us! But decades of searching and hundreds of millions spent have yielded no evidence of life other than us. Curious, eh? That’s what’s called the Fermi Paradox. To quote the New York Times, “If life is so easy, someone from somewhere must have come calling by now.”

We humans should be late to the game of civilizations, having only popped up a mere 300,000 years ago and taking roughly the same amount of time to even leave our planet. Our star, the Sun, is relatively young, being only 4.6 billion years old compared to the universe’s 13.8 billion. So this means there are trillions of stars, most likely more, that have been around long before us, many containing habitable planets. So surely, some of these must have developed intelligent life. They had to have eventually explored the idea of interstellar travel, and no matter how fast or how slow it took, they should have been able to fully colonize their galaxies in a few million years at most; a blink of an eye compared to the age of the universe. As of now, we’ve got 4 billion stars containing Earth-like planets in their habitable zones. Surely one of these must have had a species develop interstellar space travel or even regular space travel. Especially if one or two such civilizations were in our galaxy and have since long disappeared, we should see at least a probe in our star system from curious explorers. Or solid evidence of past visitors such as ruins of megastructures. Giant space stations, Dyson swarms orbiting the sun or ringworlds. Yet we have absolutely zilch. So why haven’t we found intelligent life yet?

The Great Filter

A common theory is the Great Filter theory. The Great Filter represents a series of barriers that makes becoming a galactic civilization difficult, or even impossible. The Great Filter may be behind us, which would be great and would explain a lot, or it’s ahead of us, which is awful.

If it is behind us, that means that life is rare, and to have gotten as far as we did is a truly impressive feat. It’s all smooth sailing from here. On Earth, at the very least, dozens of specific, one-time events had to happen for the evolutionary tree to even branch out into us homo sapiens instead of sticking with simple bacteria in the ocean. So first, a bunch of dead things need to get together into self-replicating patterns(DNA) capable of changing. Then single-celled organisms must form somehow. Then, multicellular organisms with animal cells. For that to happen, you’ll need eukaryotic cells, which evolved from prokaryotic cells. This evolution resulted when a cell swallowed another cell(a mitochondrion), and instead of digesting it, chose to start a symbiotic relationship with it, with the larger cell providing protection and resources while the mitochondrion produces energy for its host, providing the necessary energy for eukaryotic cells to evolve into complex multicellular organisms. As far as we know, this event only happened once. Then, intelligence has to develop. From an evolutionary standpoint, large brains don’t make sense. They won’t help us humans outrun cheetahs or fight them. They consume a ridiculous amount of energy as well(roughly a fifth) and for what? Even with our massive brains, it took hundreds of thousands of years for us homo sapiens to figure out, “hey, farming is much easier than moving around constantly to find food.” Even today, 16.4 million Americans think chocolate milk comes from brown cows! Come on! We’re lucky that intelligence even worked out for us, who knows how it worked out for other species? Even if intelligence develops, a species might not be able to utilize it. Shoot, dolphins are pretty smart, but they haven’t even built a single fish farm, much less a particle accelerator. Once a species has advanced enough to develop space travel, they need to have the desire to begin colonizing. Maybe other species aren’t as expansionist as humans. Maybe it’s way more expensive than we think, and the knowledge that a colony would eventually seek independence from a government light-years away prevents them from bothering with it.

Extinction events are sprinkled throughout the epochs of Earth’s history, with 99.9% of all species in the history of our planet long dead. Obviously, these extinction events happened in the past, ranging from Earth’s natural climate cycles making things too hot or too cold for species alive at the time to volcanic eruptions, potential gamma-ray bursts from black holes, or most recently, an asteroid strike. Who knows if something like this could happen in the future? Events such as these may be relatively spread out over time but are very, very devastating. As far as we have seen, such cataclysmic events are merely roadblocks to the development of an intelligent species.

So what if the Great Filter were ahead of us? That would mean life is pretty common out there, but it’s the nature of advanced civilizations to destroy themselves, one way or another. We’ve gotten past the not-so-easy parts, but we much to deal with ahead of us. Even at our current stage, we’ve almost initiated nuclear war plenty of times, we have yet to resolve climate change, and we’re concerned about the development of technologies(AI, nanotech, genetic engineering) with the potential to go haywire and kill us all. As of now, we have yet to find a way to detect non-intelligent life on other planets, but when we do, let’s hope that we find nothing.

The Dark Forest Theory

The Dark Forest theory, as the name suggests, compares the environment of space to that of a dark forest. We have no clue what’s out there, but if we extrapolate the behavior of aliens from our own behavior, it’s pretty damn scary.

It is the nature of life to survive, compete for resources, and seek to multiply and thus must compete with each other to achieve these goals, with competition favoring species or beings with advantageous traits. These traits have clearly shown themselves throughout human history, with empires rising and falling trying to seize as many resources as possible to secure the futures of their citizens. Our expansionist, competitive nature has allowed us to conquer and subjugate our planet and its resources for our gain, and concerns over the future of our planet and desire for more resources have led us to begin exploring the final frontier.

It’s likely that a similar “game of species” happens on other planets harboring life too, thus we can logically conclude that an alien species that was capable of taking over their planet has similar traits to us, making them potentially dangerous as competitors.

This theory could explain why we haven’t heard anything despite decades of searching; everybody has the same thought in mind. This fear is also what prevents us from transmitting a lot; what are we supposed to do if we receive a reply? What if we accidentally knock on the door of an unfriendly civilization? Even if there’s a small chance a belligerent civilization answers our call, the consequences certainly won’t be small. Out of fear, a civilization’s first move upon seeing another intelligent species would be to eliminate it, otherwise, that species could eliminate them. Classic prisoners’ dilemma. Can you trust the other civilization not to destroy you first? With the distance between civilizations, communication is impractical, technological gaps will vary widely and will get wider over time, and cultural and linguistic differences put civilizations that discover each other in a state of uncertainty. It’s in the best interest for a civilization to strike first; the longer you wait, the more advanced the other civilization gets. Even a technological gap of less than a decade is insane-American P-51 Mustangs and P-47 Thunderbolts from WWII would stand no chance against the F-86 Sabre or a Soviet MiG-15 introduced at the end of the decade. Who knows how large that difference could be on interstellar time scales?

Why Would Aliens Care?

Extrapolating from what we have done, it’s likely aliens will have developed mind-numbing mass media and entertainment before they’ve figured out how to send a member of their species to another planet. Shoot, what’s easier? Making Snapchat from scratch, or figuring out the logistical issues of having a permanent colony on a planet with close to no atmosphere or arable land? Most of our needs can easily be met with technology these days, and our society has become so digitized corporations have decided to create a metaverse as an evolution of the mobile internet. If you don’t know exactly what a metaverse is, think of the OASIS in Ready Player One. A closer version present in our society already would be Roblox. To take it a step further, a species might just build a supercomputer called a Matryoshka Brain and upload the minds of all their members into it.

Maybe It’s Deliberate?

Perhaps alien life is abundant, and they’re deliberately hiding as best they can to ensure our natural development as a species before inviting us to join some Federation of Planets. This is the Zoo Hypothesis and relies heavily on assumptions that many different alien cultures share the same ideal. All it takes is one bad apple to spoil the whole barrel, or in this case, one rogue civilization to pop by our planet and ask to be taken to our leader.

A related theory is the laboratory hypothesis, proposed by former MIT scientist John Allen Ball, who theorized that Earth is being used as part of an experiment by advanced civilizations. Douglas Adams’s The Hitchhiker's Guide to the Galaxy entertains this solution to the Fermi Paradox, depicting Earth as a supercomputer designed to figure out the “Ultimate Question to life, the universe, and everything,” after finding out the ultimate answer to life, the universe, and everything was an unimpressive 42.

Nutter Theories

One theory with absolutely no evidence whatsoever is the simulation/planetarium theory. Whatever beings created this simulation made it appear so that the universe is devoid of life.

A plausible explanation is that aliens are here already; we do have a decent amount of UFO sightings that still remain unsolved, such as the many government-released videos of UFOs being spotted by Air Force and Navy pilots. Of course, there is no evidence these UFOs were of extraterrestrial origin, but we have no evidence that they weren’t either, hence why they’re still Unidentified Flying Objects. Or maybe the government damn well knows that aliens are here, and they’re hiding it from us!

This is just the tip of the Fermi Paradox iceberg; any other solutions have been proposed. The search for intelligent life is still ongoing, but we won’t be expecting replies to any of the messages we’ve sent out for decades or even centuries. Overall, the discovery of any life other than us is a significant risk to our species, and the best-case scenario would be an empty universe, waiting for us to spread life throughout it.


Carl Sagan. Contact. Chapter 3, p. 49

Ward, Peter D.; Brownlee, Donald (2000). Rare Earth: Why Complex Life is Uncommon in the Universe (1st ed.). Springer. p. 368.

Lineweaver, Charles H. “Paleontological Tests: Human-like Intelligence Is Not a Convergent Feature of Evolution.” ArXiv:0711.1751 [q-Bio], Nov. 2007. arXiv.org, http://arxiv.org/abs/0711.1751.

Stephen, Webb. 75 Solutions to the Fermi Paradox and the Problem of Extraterrestrial Life

Overbye, Dennis. “The Flip Side of Optimism About Life on Other Planets.” The New York Times, 3 Aug. 2015. NYTimes.com, https://www.nytimes.com/2015/08/04/science/space/the-flip-side-of-optimism-about-life-on-other-planets.html.

Behroozi, Peter, and Molly S. Peeples. “On the History and Future of Cosmic Planet Formation.” Monthly Notices of the Royal Astronomical Society, vol. 454, Dec. 2015, pp. 1811–17. NASA ADS, https://doi.org/10.1093/mnras/stv1817


Richardson, Michael W. How Much Energy Does the Brain Use? https://www.brainfacts.org:443/brain-anatomy-and-function/anatomy/2019/how-much-energy-does-the-brain-use-020119. Accessed 21 Feb. 2022.

“Analysis | The Surprising Number of American Adults Who Think Chocolate Milk Comes from Brown Cows.” Washington Post. www.washingtonpost.com, https://www.washingtonpost.com/news/wonk/wp/2017/06/15/seven-percent-of-americans-think-chocolate-milk-comes-from-brown-cows-and-thats-not-even-the-scary-part/. Accessed 21 Feb. 2022.

“The Disc of the Milky Way Is Bigger than We Thought.” Instituto de Astrofísica de Canarias • IAC, https://www.iac.es/en/outreach/news/disc-milky-way-bigger-we-thought. Accessed 21 Feb. 2022. https://www.pbs.org/wgbh/evolution/extinction/massext/statement_03.html#:~:text=Of%20all%20species%20that%20have,of%20a%20sixth%20mass%20extinction.

Should We Call the Cosmos Seeking ET? Or Is That Risky? - The New York Times. 6 Sept. 2015, https://web.archive.org/web/20150906144552/http://www.nytimes.com/aponline/2015/02/13/science/ap-us-sci-calling-the-cosmos.html.

“Where Are They?” MIT Technology Review, https://www.technologyreview.com/2008/04/22/220999/where-are-they/. Accessed 21 Feb. 2022.

Barnes, Julian E., and Helene Cooper. “U.S. Finds No Evidence of Alien Technology in Flying Objects, but Can’t Rule It Out, Either.” The New York Times, 3 June 2021. NYTimes.com, https://www.nytimes.com/2021/06/03/us/politics/ufos-sighting-alien-spacecraft-pentagon.html.