Skip to content
Hard Science

Why aliens are likely to be AI

Perhaps we should be searching for “other Mercurys” rather than “other Earths.”
a group of people standing in front of a large UFO
Credit: cfhdesign / Adobe Stock
Key Takeaways
  • Fundamental biological limitations will make long-distance space travel all but impossible for organisms. AI is more suitable.
  • In fact, it is just about inconceivable for any advanced civilization, particularly a spacefaring one, to exist without AI.
  • Therefore, we should expect more planets in the Universe to be populated by AI than by Little Green Men.

With powerful new chatbots and AI-powered apps and search engines released practically every day, concern about the rapid advance of artificial intelligence has heated up recently to near obsession. And with good reason. The risk of humans losing control over AIs smarter — or at the very least faster — than us has been recognized for quite a while, notably in science fiction films like The Terminator.

As with all new technologies, AI has its pluses and minuses. But for space exploration—meaning exploration beyond our immediate cosmic neighborhood—it is probably essential. In fact, an advanced space program without AI is difficult to envision.

Advanced civilizations will require AI

That goes not just for us, but for anyone “out there” who is likely to visit us. Even though most movies about aliens depict biological creatures arriving on Earth, this is unlikely to happen. Crossing interstellar space would take them a very long time — so much time that it makes little sense to send short-lived, perishable organic bodies.

Let’s look at the life spans of some species on Earth. Humans live about 80 years, on average, which is much longer than most animals. Dogs have a life span of only 10 to 13 years, parrots about 50 years. Even the African elephant lives only 60 to 70 years. Some animals like turtles, whales, or certain fish reach 200 years of age or more. But these are exceptions. Life expectancy for nearly all species on our planet is under 100 years.

And it’s not like our bodies perform at peak capacity for that entire span. In the case of humans, we should probably discount the first 20 years or so, during which our capabilities are still developing, and the last 20 years of aging. Prime time for humans is no more than 40 or 60 years, even in the best-case scenario.

Now consider the realities of interstellar travel. To reach other solar systems, current thinking is that we’ll need to build light sails that can reach maybe ten percent of the speed of light. That gets us to Alpha Centauri in 40 years or so — an entire adult human lifespan. And that’s just one-way. Most astronauts would want to return home after visiting another solar system, but without some kind of time dilation or other exotic physics, that would be out of the question.

Even if we could reach 80 percent of light velocity with some advanced propulsion system, round trips within a single adult lifetime would be possible only for planets a mere 24 light-years away, not accounting for any time spent exploring the planet. Speculative, faster-than-light travel would help some, but not as much as you might think. Any way you slice it, travel through interstellar space would still be extremely long, dangerous (asteroids! radiation!) and exceedingly boring for any biological organism, even if some freezing technology could be invented to stop aging during the trip. The same logic applies to any intelligent aliens wanting to visit us.

AI astronauts

The likely solution, then, is artificial intelligence and artificial “bodies” that could better withstand the rigors of space travel. For that reason, we shouldn’t expect visiting aliens to be organic creatures.  

There is, of course, some middle ground between all-natural and all-artificial bodies, and 21st century technology has already arrived at that point. In Andy Clark´s words, we are naturally-born cyborgs. More and more technologically advanced body parts are invented every day, from titanium plates to pacemakers. No question, this trend will keep on going.

But our organic bodies are still fragile and limited. We may extend our natural lifespans by several tens of percent, but eventually critical parts will break down. With that in mind, some futurists picture uploading our brains to computers. Anders Sandberg and Nick Bostrom from the Future of Humanity Institute outlined some of the challenges in reaching that goal, and even provided a roadmap. Another pair of futurists, Alexey Turchin and Maxim Chernyakov, went a step further and envisioned an “Immortality Roadmap” using AI to digitally reconstruct people. The AI would take DNA and other information from a recently deceased person and reconstruct them in a simulated world. (Of course, whether that simulation is really you is a question we probably can’t answer until we try it out.)

Robots, not Little Green Men

Given its fast-growing capabilities, the ubiquitous presence of AI in all aspects of human activity appears to be unstoppable. Even so, some alien civilizations farther ahead of us on the evolutionary curve already may have decided to put a stop to it, accepting their own mortality instead. But surely not all of them. And for that reason, we should expect more planets in the Universe to be populated by AIs than by the Little Green Men of 1950s science fiction.

This could lead to a fundamental shift in our approach to searching for intelligent extraterrestrial life.  Rather than look for signs of biology, we might be on the lookout for planets more suitable to AI. Seth Shostak of the SETI Institute is among those who has advocated for this strategy. Instead of searching for worlds exactly like our own, we might identify planets that receive a much higher amount of solar energy and are rich in silicon and certain trace metals. Maybe it’s “other Mercurys” we really should be looking for, not “other Earths.”


Up Next