Definition:

Named after Italian-American physicist Enrico Fermi, this theory explores the apparent contradiction between the lack of evidence for extraterrestrial civilizations, and various high estimates for their probability. [REF]

Deconstruction:

“Where are they?”

This is the question that is the origin of, and central thesis, behind the Fermi Paradox.  Rumor has it, Mr. Fermi posed this query at a lunch meeting in 1950 with some Los Alamos National Laboratory physicist colleagues.  This was likely a pretty nerdy bunch, with a high prevalence of pocket protectors and thick glasses.

4 years later, Enrico Fermi died, but his paradoxical question lives on to this day.

In more specific terms, the Fermi Paradox asks why have we never met, seen, or even detected alien life from Planet Earth, despite the nearly infinite expanse of the known universe.

The logic back then was that based on the size and scope of space, innumerable stars many of which have inhabitable planets circling, combined with the potential for development of intelligent life, and feasible interstellar travel advancements, Earth should have already been visited by aliens several times over its existence. 

Yet no extraterrestrials have made contact, to our knowledge, even 70 years after Fermi’s proclamation.   

​

The size, scope, and composition of the known universe is pretty well accepted by scientists, so the crux of the alien debate is the likelihood for life to come into existent, become intelligent, pursue intergalactic travel, then find and engage with our world.  Let’s explore each of these considerations in more detail.

The Drake equation attempts to predict the probability of intelligent life, but many of the input terms are completely unknown guesses, even for those knowledgeable in the field.  Uncertainty analysis shows that the two most likely outcomes are that there are hundreds of civilizations in our own galaxy, or that we are completely alone throughout the entire universe.  Overall, this isn’t a very helpful conclusion in regards to solving the Fermi Paradox.

Let’s make the assumption that intelligent alien life exists somewhere out there, which is a huge leap.  What are the chances these beings are capable of traveling throughout the universe, and if they are, how likely is it they will find and visit Earth?

​

One needs only to look at our own planet’s space exploration, the only data point we have, to see how the proclivity for space travel has evolved.  The answer is very slowly. 

​

The United States first landed on the moon in 1969, spurred on by a space race with the U.S.S.R.  While the mission premise was well founded, without sufficient political motivation from J.F.K and others, this project would not have happened on the incredibly rapid 8-year timeline, if ever.

​

Now consider our anemic history of space travel since then.  The last human set foot on the moon in 1972, almost half a century ago.  Sure, corporate visionaries like Richard Branson, Elon Musk, and Jeff Bezos are driving the next wave of space exploration and travel, but without government funding and support these grandiose plans will likely take decades to pan out. 

​

In reality, the only reason for the globe to unite in space exploration is if the wonderful planet we currently inhabit is in trouble, from either internal or external factors.  In that scenario, searching for extraterrestrial life and perfecting our interstellar travel capabilities may not be very high on the priorities list. 

​

For those who are skeptical, just watch Armageddon again.  Bruce Willis and Ben Affleck know their stuff.

​

If a global emergency is necessary to encourage and facilitate intergalactic travel, it doesn’t bode well for the theory that lots of alien civilizations are flying around on random exploratory trips.

Still, for sake of argument let’s assume there is a more advanced, and sufficiently motivated alien civilization who can easily travel around the universe at reasonable speeds, in interstellar travel terms.  Now they just need to find Planet Earth.

​

The magnitude of space is nearly impossible to fathom.  For this analogy, let’s just focus on our own galaxy, rather than the entire observable universe.

​

Estimates for the number of stars in the Milky Way vary, and are steadily increasing as our observation techniques improve; we’ll used 600 billion stars to make the math easier.  For this simple thought experiment, each star is represented by a single grain of sand.  Assuming roughly 1 billion granules of sand per cubic foot, we can cover an NFL football field with a layer of sand 1/8” thick, which will contain the desired 600 billion planet equivalent particles.

This simplification ignores the spacing between the stars, likelihood of habitable planets clustering in the galaxy, and numerous other complicating variables.  But it’s a fine proxy.

Now you, representing an alien civilization with unencumbered travel capabilities, can walk across the football field using any techniques you deem reasonable to find the one black grain, representing Planet Earth, is the thin coating of fine, beige beach sand.

​

This seems like a pretty difficult task, but not impossible.  Given sufficient time, and resources, you could probably come up with a plan to grid off the field and methodically collect, evaluate, and filter each grain of sand.

​

However, this analogy is incomplete, since you, at human size, are massive in scale relative to our model galaxy.  By walking across the field, or sifting sand through your fingers, you are essentially traveling an incomprehensible rate of speed. 

​

Instead, imagine you are trying to find the black grain of sand as a lone ant, crawling across the flat expanse of sand. 

​

Even ant sized with human intelligence, this project becomes quite a bit tougher, simply as a function of the scope of the task.  Plus, the search now becomes a true 3-dimensional problem since the sand thickness now becomes meaningful.

​

However, this is still not a fair comparison, because each grain of sand represents a star, with all associated planets, like our own solar system.  So, a single human, on Planet Earth, is closer in scale to a single crystal of silica in an individual grain of sand. 

​

But you get the point.  Even in our own galaxy, the scope of the required exploration is massive.      

​

Still, there’s a chance, albeit a minute one.  Say aliens find Earth, that black spec in the sea of white.  How will they know we are here, and how can we acknowledge their presence? 

​

In most sci-fi movies, the alien ships just show up in our atmosphere, easily visible to the naked eye.  Also, they are usually conveniently similar in scale to humans in both their transportation vessels and their physical forms.  Think Independence Day.

​

However, it’s very plausible that we won’t even recognize activities as extraterrestrial in origin, since we can’t understand, or even detect them.  Think about the arc of human messaging, from cave paintings, to written letters, to e-mail posts.  All this occurred in the span of 50,000 years, a blip on the galactic timeline. 

​

Who knows what other forms of more advanced communication technology may exist in the future beyond our new 5G cellular world: optical queues, telepathy, harnessing neutrinos, dark matter, something else we don’t even have words for yet?

​

Lastly, there’s the time component.  One of the key elements to an alien encounter is that we need to meet them along two axes: distance and time.

​

Research suggests there’s a high probability for recurring extinction events in space due to its volatile nature, which could shorten the feasible exploration timeline for developed civilizations.  Again, short is relative as we’re talking on million-year time scales.  Still, if it rains on the football field during your investigation, sending rivers of water streaking across the surface, you’re going to be an unhappy ant, and search for a random black grain of sand may take a back seat.

​

The magnitude of space is immense as already discussed.  Multiplying by the time scale of the known universe creates an unfathomable blank space within which two discrete points must meet.

​

This realization means we’re probably more likely to discover a self-sufficient probe from an alien species, drifting through space like an asteroid, generations after its creators deployed it.  Or detect a communication signal from thousands of light years away, sent by some form of intelligent life well in the past. 

But the likelihood of direct interaction, or even two-way messaging, between us and another living entity in the universe is fleetingly slim.

​

Fermi Paradox proponents use the law of large numbers to justify the prevalence of intelligent civilizations who will be contacting us any day now.  However, it’s just as easy to use these same incomprehensible vast values to show how unlikely an alien encounter with Planet Earth is. 

​

Are we alone in the universe?  Only space, and time, will tell.

Details:

• Long form article explaining some of the math and assumptions surrounding the paradox. [REF]

• Drake Equation calculator with scientific context; good luck coming up with reasonable inputs for all of the terms. [REF]

• Good overview of the 1960’s Space Race with key dates and events. [REF]

• Article comparing Earth’s total sand quantities to number of stars in the universe, with a neat twist at the end. [REF]

• A contrarian take on the Fermi Paradox. [REF]