Mister Fermi, Where is Everybody??

I didn't expect to be dedicating two articles on The Three Body Problem trilogy (last week's article here), but I just finished the second book and it was so good I had to have a sequel of my own!

A few years ago when I was still just an investment banking intern in New York, one of my fellow interns asked me, "Hans, I heard you're really into space! What're your thoughts on the Fermi Paradox?" And I still remember it because it was a somewhat embarrassing moment for me - I'd  never heard of the Fermi Paradox at the time!

The Fermi Paradox is just a fancy way of asking, "WHERE ARE ALL THE ALIENS?!" In more scientific terms, it's a cosmological contradiction that states: given the high probability that extraterrestrial life exists, why haven't we seen any evidence of it? The high likelihood aliens exist is commonly supported by the Drake equation, which lays out the following postulates:

  • There are billions of stars in the Milky Way similar to the Sun
  • Many of these stars will have Earth-like planets
  • Some of those planets will develop intelligent life
  • Some of these intelligent alien civilizations will develop interstellar travel. Even with relatively slow spacecraft, the entire Milky Way can be explored in a few million years
  • Since the Sun and other similar stars are billions of years old, that should be plenty of time for alien contact

Although physicist Enrico Fermi wasn't the first to consider this paradox, it's named after him because one day he was having lunch with some fellow physicists discussing UFOs and faster-than-light travel, and he allegedly exclaimed, "But where is everybody?"

Through the years various cosmologists and other scientists have given their best guesses for why E.T. hasn't shown up on our doorstep, and they roughly fall into the following categories (Wikipedia provides more detail)

  • The Earth and humanity are special, and aliens simply don't exist. Or if they do, they are not intelligent enough to communicate
  • Intelligent species always come to destroy themselves eventually
  • It's simply not possible to traverse the enormous distances between stars
  • We are not listening properly or are incapable of recognizing the presence of aliens even if they revealed themselves
  • We are intentionally not being contacted
  • Aliens are already secretly here!

Humanity is a very young species. The radio telescope has only been around since 1937, so we'd be tough to detect

While I have no idea which is correct, I found a super interesting theory in Cixin Liu's The Dark Forest, the second book in The Three Body Problem trilogy, that serves as a pivotal aspect of the plot (warning: minor spoilers ahead). Essentially, the main character is tasked with developing the field of "cosmic sociology" based on two fundamental axioms: 1) every civilization's goal is survival, and 2) the Universe has finite resources

Alien invasion has always been a motif in science fiction. One of my favorites: the Covenant fleet from Halo!! I miss middle school :(

With that in mind, his theory is as follows: Assume humanity discovers another alien civilization. It's safe to assume that if we can detect aliens, they'll be able to detect us eventually too. However, it is impossible to tell whether the aliens are benign or hostile, and the extreme distances between stars preclude any hope of continuous dialogue to dissipate mistrust. This inevitably leads to a "chain of suspicion," meaning that even if our inclination is to believe the aliens are benign, how can we be sure they reached the same conclusion about us? If they decide we're hostile, interstellar conflict will arise anyway. And even if the aliens are primitive, given the exponential rate of technological innovation, in just a few centuries they may catch up and quickly become a threat, so we can't just leave them alone. 

Therefore, the only viable strategy for any civilization is to hide their existence completely, and upon encountering another civilization, preemptively annihilate it without alerting anyone else to your own location! A pretty grim theory, if you ask me. The author describes this view of the Universe as "hunters stalking in a dark forest", hence the name of the book

The Alliance Fleet versus the Reapers from Mass Effect 3 - one of my favorite space battles ever!

This would explain the Fermi Paradox: we've never discovered aliens because they intentionally hide themselves, and thus far we are fortunate that no extraterrestrial civilization has found us yet, otherwise we would be promptly obliterated.

Now consider this fact: over the past few decades, humanity has occasionally sent out intense radio wave bursts conveying basic information about human civilization on Earth, the most famous of these being the Arecibo message in 1974. On top of that, the Voyager Golden Records attached on the Voyager 1 and 2 probes even included a detailed diagram of the Earth's location relative to 14 nearby pulsars!

Left: The Arecibo message beamed info about DNA, the Solar System, and a human figure towards the star cluster M13
Right: The pulsar map is the bottom left figure

If the theory of the dark forest is true, these messages aren't just foolish, they're utterly suicidal! Do I have you nervous yet? Indeed some scientists have cautioned against such active broadcasting, most notably Stephen Hawking, and it's definitely up for debate whether or not searching for aliens is prudent. But if it's any comfort to you, I don't live my life in fear of alien invasion - my hope is that the theory of the dark forest is wrong, and that any aliens that have mastered such advanced technology as interstellar travel have evolved beyond the violent tendencies that so often keep humanity in conflict

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