Where is all the ‘alien life?’ – Fermi Paradox and other theories

We should openly admit that when we happen to be under a starry night and see a sight similar to this, we all have a react in a different and interesting way. Some people are left boggled by the immense size of the universe, others by the sheer glamour of the scene and if you’re anything like me, you’re paralyzed by the sudden realization that you have a negligible impact on the universe. The point is, we all feel something.


When he looked up at the sky, Italian physicist Enrico Fermi too felt something, a thought that lingered around the question “Where is everyone else?” It’s been half a decade since Fermi passed on, but he left us with a fundamental query and an idea.

Fermi realized that in a universe as old and vast as this, there should be plentiful planets that harbor life, and so he immediately realized that there should also have been more than enough time for aliens to have developed sufficient technology to travel the galaxy. However, they don’t seem to be zooming past us and visiting us.

“This sounds a bit silly at first. The fact that aliens don’t seem to be walking our planet apparently implies that there are no extraterrestrials anywhere among the vast tracts of the Galaxy. Many researchers consider this to be a radical conclusion to draw from such a simple observation. Surely there is a straightforward explanation for what has become known as the Fermi Paradox. There must be some way to account for our apparent loneliness in a galaxy that we assume is filled with other clever beings.” – SETI.

Via Terry Hancock (down under observatory)

SETI (The Search for Extraterrestrial Intelligence) is a global, unanimous community which encompasses all work done to seek extraterrestrial life. Any and all people that dedicate their work of astronomy to seeking out extraterrestrial life are the at the crux of SETI.

The Fermi Paradox

“The Fermi Paradox seeks to answer the question of where the aliens are. Given that our star and Earth are part of a young planetary system compared to the rest of the universe — and that interstellar travel might be fairly easy to achieve — the theory says that Earth should have been visited by aliens already.”

Related: Our Message to Aliens

It is already known that the entire universe is gigantic and ancient. The estimations that the universe is 92 billion light years in diameter and that it is nearly 13 billion years old would go to show that there has been enough time for other life to develop intelligently and become advanced enough to hike over to us.

“Fermi realized that any civilization with a modest amount of rocket technology and an immodest amount of imperial incentive could rapidly colonize the entire Galaxy. Colonization of the Milky Way should be a quick exercise.”

However, the numbers do not favor us in the slightest. The calculations say that for every star in the observable universe, there is an equal number of galaxies out there. Let that sink in for a second. So, as many stars, as there are in the Milky Way Galaxy alone (100 to 400 billion), there is an equal number of galaxies in the Universe.

It also states that for every grain of sand in the world, there are 10,0000 stars.

There are two parallel debates in the science world about the Fermi Paradox. One revolves around how many ‘Sun-like’ stars there are (in terms of luminosity, size, and temperature), and the second debates about how many of those stars have an Earth-like planet orbiting them(in terms of liquid water and the ability to sustain life like on Earth). Even if we consider the lowest of estimates, which says that 1% of planets orbiting stars in the Universe are Earth-like, that number still means that there are approximately 100 billion-billion Earth-like planets.

So, for every grain of sand on Earth, there are about 100 Earth-like planets out there. Think about that the next time you’re on the beach.

The Fermi Paradox has been critically acclaimed by many renowned scientists and the general scientifically literate population for its strong argument. It gets more and more speculative, though.

“Let’s imagine that after billions of years in existence, 1% of Earth-like planets develop life (if that’s true, every grain of sand would represent one planet with life on it). And imagine that on 1% of those planets, the life advances to an intelligent level like it did here on Earth. That would mean there were 10 quadrillion, or 10 million billion intelligent civilizations in the observable universe.

The Great Filter

The Great Filter is perhaps the most logical and valid explanation to solve the Fermi Paradox. The Great Filter has one of two possibilities. It says that in the process of evolving from a bare, lifeless planet to a galaxy fairing civilization, there is a step/obstacle that most civilizations fall short of.

The first possibility is that we, sometime in our evolution passed that obstacle and we are one of the rare civilizations to ever do so. That’s the good news: it means we’re one of the first or one of the very few species that will reach this level of technology.

The second possibility is that the obstacle hasn’t been reached yet and that it is ahead of us. That’s bad news because it means there is some danger, likely completely unknown to us, that can wipe us out in a way that is very difficult or impossible to avoid. It would mean that, for example, we should be extremely careful with certain kinds of scientific experimentation that we do not fully understand.

We don’t know which two of the possibilities is the one we will face.

While it’s generally good to be optimistic, it may be more advantageous to lean towards believing that the Great Filter lies ahead of us. Apophenia, the human tendency to recognize patterns from random data helps us because species with a healthy, higher sense of apophenia tend to protect themselves, reproduce and become the norm, as Michael Stevens says:

“If there’s ambiguity to whether that thing in the shadows is a threat or just a shadow, it’s advantageous to air on the side of threat.”

Being cautious about our progress as a species will make us more careful, and less likely to fall short of the great filter, if it is in fact, ahead of us. While of course, the Fermi Paradox is at its core only a theory. We can’t say with any certainty if whether we will hit the Great Filter in a million years or tomorrow night.



We may have been born too early to explore the cosmos and too late to explore the Earth, but our lives on this blue marble will still not be wasted. Nowhere in a quintillion planets in our universe will there be someone just like you. That means something special.

“There is good out there in the universe that has your name on it. Nobody can get your good.” – Les Brown

As always, thanks for reading.


Space.com – Fermi Paradox

WaitButWhy – Fermi Paradox

SETI on the Fermi Paradox

The Great Filter – And Why It’s Scary

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