Seti: why extraterrestrial intelligence is more likely to be artificial than biological

Is there intelligent life in other parts of the universe? It is a question that has been debated for centuries, if not millennia. But only recently have we had a real chance to find out, with initiatives like Seti (Search for Extraterrestrial Intelligence) which uses radio telescopes to actively listen for radio messages from extraterrestrial civilizations.

What should we expect to detect if these searches are successful? My suspicion is that they are highly unlikely to be little green men, something I speculated about in a talk at a Breakthrough Listen (a Seti project) conference.

Suppose there are other planets where life began and that it followed something like Darwinian evolution (which need not be the case). Even then, it is highly unlikely that the progression of intelligence and technology will occur at exactly the same rate as on Earth. If it was significantly delayed, then that planet would clearly not reveal evidence of extraterrestrial life to our radio telescopes. But around a star older than the Sun, life could have had a head start of a billion years or more.

Human technological civilization only goes back millennia (at the most), and it may be only another century or two before humans, composed of organic materials such as carbon, are surpassed or surpassed by inorganic intelligence such as AI. The processing power of the computer is already increasing exponentially, which means that AI in the future can use much more data than today. It seems to follow that it could become exponentially smarter, surpassing human general intelligence.

Perhaps a starting point would be to improve ourselves with genetic modification in combination with technology, creating cyborgs with parts organic and part inorganic. This could be a transition to fully artificial intelligences.

AI may even be able to evolve, creating ever better versions of itself on a time scale faster than Darwin’s over billions of years. Organic intelligence at the human level would then be only a brief interlude in our “human history” before machines take over. So if alien intelligence had evolved in a similar way, it would be highly unlikely that we would “catch” it in the short span of time when it was still incarnated in biological form. If we were to detect extraterrestrial life, it would be far more likely to be electronic than flesh and blood, and it may not even reside on planets.

Therefore, we must reinterpret the Drake equation that was established in 1960 to estimate the number of civilizations in the Milky Way with which we could potentially communicate. The equation includes several assumptions, such as how many planets there are, but also how long a civilization can broadcast signals into space, which is estimated to be between 1 billion and 100 million years.

But the lifespan of an organic civilization may be millennia at most, while its electronic diaspora could continue for billions of years. If we include this in the equation, it seems that there may be more civilizations than we thought, but that most of them would be artificial.

We may even want to rethink the term “alien civilizations.” A “civilization” connotes a society of individuals. In contrast, the aliens could be a single integrated intelligence.

message decoding

If Seti were to succeed, it would be unlikely that he would log decipherable messages. Instead, it can detect a byproduct (or even a malfunction) of some super-complex machine far beyond our comprehension.

Seti focuses on the radio part of the electromagnetic spectrum. But since we have no idea what’s out there, we should clearly explore all wavebands, including the optical and X-ray parts. Instead of just listening to the radio transmission, we should also be on the lookout for other evidence of phenomena or unnatural activities. These include artificial structures built around stars to absorb their energy (Dyson spheres) or artificially created molecules such as chlorofluorocarbons (non-toxic, non-flammable chemicals containing carbon, chlorine and fluorine) in the atmospheres of planets. These chemicals are greenhouse gases that cannot be created by natural processes, which means they could be a sign of “terraforming” (changing a planet to make it more habitable) or industrial pollution.

I would say that it would even be worth looking for traces of extraterrestrials in our own solar system. While we can probably rule out visits by human-like species, there are other possibilities. An alien civilization that had mastered nanotechnology could have transferred its intelligence to tiny machines, for example. Then it could invade other worlds, or even asteroid belts, with swarms of microscopic probes.

And even if we received a decodable radio message, how could we know what the superintelligent sender’s intention was? We have absolutely no idea: think of the variety of bizarre motives—ideological, financial, and religious—that have driven human endeavors in the past. They can be peaceful and curious. Even less annoyingly, they may realize that it’s easier to think at low temperatures, moving away from any star or even hibernating for billions of years until it cools down. But they could be expansionist, and this seems to be the expectation of most who have thought about the future trajectory of civilizations.

The future of intelligence

As the universe evolves, intelligent species can become incredibly intelligent. Just take our own future. Eventually, stellar births and deaths in our galaxy will proceed gradually more slowly, until it shakes up when the Milky Way collides with the Andromeda galaxy in about a billion years. The remnants of our Andromeda galaxy and its smaller companions within our local group of galaxies will thereafter clump together into an amorphous galaxy, while distant ones will recede from us and eventually disappear.

But our remnant will continue for much longer, long enough, perhaps, for a civilization to emerge that could be in possession of enormous amounts of energy, even harnessing the entire mass of a galaxy.

This may be the culmination of the long-term trend for living systems to become more complex. At this stage, all the atoms that were once in the stars and gas could be transformed into a giant organism on a galactic scale. Some science fiction authors contemplate engineering on a stellar scale to create black holes and wormholes, bridges connecting different points in space-time, theoretically providing shortcuts for space travelers. These concepts go far beyond any technological capabilities we can imagine, but not in violation of basic physical laws.

Are we artificial?

Posthuman intelligences can also build computers with enormous processing power. Humans are already capable of modeling some fairly complex phenomena, such as the weather. However, more intelligent civilizations can simulate living beings, with real consciousnesses, or even entire worlds or universes.

How do we know that we are not living in such a simulation created by technologically superior aliens? Perhaps we are nothing more than a bit of entertainment for some supreme being who is running such a model? In fact, if life is meant to be able to create technologically advanced civilizations that can make computer programs, there may be more simulated universes than real ones, so it’s conceivable that we’re in one of them.

This guess may sound outlandish, but it is based on our current understanding of physics and cosmology. However, we should surely keep an open mind about the possibility that there is a lot we don’t understand. Perhaps the laws we see and the constants we measure are only “local” and differ in other parts of the universe? That would lead to even more amazing possibilities.

Ultimately, physical reality could encompass complexities that neither our intellect nor our senses can grasp. Some electronic “brains” may simply have a quite different perception of reality. We also cannot predict or understand their motives. This is why we cannot assess whether the current radio silence experienced by the Seti signifies the absence of advanced alien civilizations, or simply their preference.