Stranger than we can imagine
Why have humans failed to find extraterrestrial intelligence? Maybe we’re making the mistake of searching for beings like us
On July 20, Russian tech billionaire Yuri Milner announced a massive and unprecedented investment in the Search for Extraterrestrial Intelligence (SETI) that’s taking the form of a $100-million, decadelong sky-survey called “Breakthrough Listen.” Backed by an international consortium of scientific luminaries, including Stephen Hawking and SETI founder Frank Drake, Milner, who trained as a physicist before making a fortune investing in Facebook and Twitter, has committed to significantly amping-up the fledgling search for alien radio signals. But is this the right approach to finding extraterrestrial intelligence?
The news has already revived the array of deep and difficult questions SETI projects provoke, including the nagging possibility that our searches have failed so far in part because they assume, as this one does, that aliens are largely like us and their technology like our own.
The notion that the heavens are inhabited by other intelligent beings is old and widespread among human cultures. In Europe and America, the invention of radio transformed the old “plurality of worlds” debate by suggesting that beings on other planets might already be transmitting — and maybe we could listen in. In 1960, American astronomer Frank Drake turned an early radio telescope towards the West Virginia sky, hoping to be inundated with extraterrestrial chatter.
Despite decades of silence, his pioneering “project Ozma” evolved into the nowfamiliar SETI acronym and enjoyed NASA funding in the early 1990s. However, in 1993, Congress yanked support for the controversial project, leaving SETI scientists to eke by on a hodgepodge of private funding, as excitement shifted to the possibility of finding microbial life on Mars and, more recently, the moons of Jupiter and Saturn. Milner’s money now changes all of this.
Motivated by the accelerating pace of exoplanet detections — especially Earthsized planets in the liquid-water-friendly “habitable zone” — Milner hopes that his investment will help scientists discover alien transmissions emanating from some of these watery worlds.
Despite the relatively small scale of various SETI searches over the past 50 years, the complete lack of any detections has critics pointing to the famous Fermi Paradox: Where is everybody?
Various answers have been posited: humans are the only intelligent life in the universe; technologically advanced civilizations quickly destroy themselves; aliens actively conceal their presence; or even the unnerving possibility that we’re part of a galactic zoo. But the dearth of evidence may simply signal a lack of imagination on our part, rather than a lack of alien intelligence.
The basic problem is that for examples of intelligent, “technologically advanced” civilizations, our sample size is exactly one — us. Basing key assumptions about alien intelligence or civilization — like the expectation that some will communicate via radio waves or optical lasers — on our own history and current technological capabilities could be way too specific. What if, rather than being alone, we’re just the only ones interested in radio right now? What if intelligent aliens perceive and order the universe in a completely different way? What if their ways of thinking, communicating and making things are to us, well, alien?
The void of space is vast and terrifying, so the idea that alien minds might evolve along a similar intellectual trajectory — and share our understanding of pi, prime numbers and radio telescopes — is comforting when faced with the more likely alternative: that alien life and “intelligence” is radically different from anything Milner’s dream team is counting on.
The sheer strangeness of some life on Earth, such as bioluminescent deep-sea creatures, still shocks us. We struggle to understand intelligence in other animals, like cephalopods, and haven’t had much luck communicating with them. There are ancient human languages still undeciphered. The notion that some aliens have developed, and still use radio, makes the big assumption that intelligent life will follow a roughly similar path of cultural and technological development as we have — but the diversity of life and cultures on Earth suggests otherwise.
Most likely, we will see evidence of extraterrestrial life in the not-too-distant future, but in the form of inferences of biological processes based on long-range analyses of exoplanet atmospheres — suggesting life, but not necessarily intelligent life.
So what will Milner get for his millions if not an alien signal? He’s already boosted the status of SETI scientists and rekindled popular interest in detecting extraterrestrial intelligence. Even if this search is initially hampered by “terracentric” assumptions, a robust SETI program will hopefully evoke deep critical reflections about the nature of life, intelligence, technology and civilization, and how utterly different these might be elsewhere in the universe.