by Jochen Szangolies
In 1950, during a lunch conversation with colleagues at the Los Alamos National Laboratory, Enrico Fermi asked the wrong question. Famously, after a discussion on the subject of recent UFO sightings, extra-terrestrial life, and the possibility of faster-than-light travel, Fermi blurted out: “But where are they?”
In that context, it was a sensible question: even given the magnitude of interstellar distances and the difficulties of bridging them, the vastness of cosmic time provides ample opportunity for an enterprising civilization to have visited any star within the galaxy several times over (for a brief recapitulation of the reasoning behind this assertion, see this previous essay). Certainly, it has been a stimulating one: it has spawned volumes of discussion, with potential solutions ranging from the optimistic to the dismal, from us inhabiting a carefully curated cosmic ‘zoo’ to every civilization self-destructing shortly after developing nuclear weapons.
But, as fruitful as this discourse has been, I want to suggest that there is a more interesting question that Fermi could have asked, one that might end up telling us much more about our place and future in the universe: “Why aren’t we them?”
Under seemingly reasonable assumptions, almost every sentient being in the universe should expect to find themselves as part of a galaxy-wide, ancient and prosperous civilization (the galactic metropolis); or, should interstellar space travel be fundamentally impossible, find whatever maximal niche they occupy (their ancestral home planet, the worlds of their solar system, a Dyson swarm around their star) filled nearly to capacity, for a time that’s of the order of magnitude of how long that niche can accommodate such a population. The argument for this is simply that for the vast majority of beings to ever exist, it will be true that they find themselves in such a situation, given ‘business as usual’—essentially, if life continues to ‘be fruitful and multiply’.
If it makes sense to apply such reasoning to our own situation (and I will argue that it does), the fact that we find ourselves very far from such a scenario demands explanation. Broadly, there are two possible answers. Read more »