Five Possible Reasons Why We Haven’t Found Aliens Yet

And why humankind is alone in the universe?

5 min readMay 9, 2022

Photo by Eddy Billard on Unsplash

The Universe is immense. Billions of galaxies, each with its own billion or so stars. Each star with its planets, each planet with its composition. The Universe is ineffably large, doesn’t matter how we look at it.

Yet, in a place so crowded with matter, why are we alone? Why is Earth the only planet to host life? Why haven’t we discovered our cosmic neighbors yet? Do they even exist?

Enrico Fermi first asked these questions in a lunchtime conversation with a colleague. Later, these questions would be synthesized into the now-famous Fermi’s Paradox. Let’s look at five possible solutions to the paradox!

1. The Great Filter

Robin Hanson proposed that the reason the Universe is so empty is that life must undergo various steps before it can become space-faring. Hanson suggested that these steps may be of varying likelihood, and achieving some may be more difficult than others.

The absence of detectable megastructures (such as Dyson spheres) may indicate that the unlikely step may be developing inexpensive space-age technology. If this step were easy, we would see the remnants of ancient super-civilizations littered throughout the galaxy, but we do not. This has a terrifying implication: intelligent life may be self-destructive.

A lot of humanity’s shenanigans seem to give credence to this hypothesis, with global warming and narrowly avoided nuclear armageddon being excellent illustrations of our stupidity.

Though the human experience lends this theory support, it may be limited by the same thing. The lack of detectable megastructures may not necessarily mean that super-civilizations do not or did not exist. It may be that megastructures are not of much use and that a truly advanced civilization would prefer nanotechnology. After all, size reductions often benefit efficiency, among other things.

Furthermore, alien engineering may not even look like engineering to us; we may just be too dumb to see what’s right in front of us. Arthur C. Clarke once said,

“Sufficiently advanced technology is indistinguishable from magic.”


I am a History Educator and a Lifelong Learner with a Masters in Global History.