Over a septillion stars in the universe. 76 sextillion of these are sun-like, with nearly all of them having some form of planets. Based on Kepler (a NASA telescope) observations, 1 in 4 of these planets are potentially habitable – terrestrial, similar to Earth in size, and located in the habitable zone (not too cold or too hot for water and life to exist). This means that there are tens of billions of habitable planets in our galaxy alone! Surely, in one of these vast worlds, there must exist some form of intelligent life?


Let me introduce you to von Neumann machines, a theoretical self-replicating spacecraft. The idea is for these probes to land on distant rocky planets or asteroids, mine resources to build factories to replicate itself, and have each one of those probes do the same throughout the galaxy. Sounds wicked, doesn’t it? While it only exists in science fiction today, these machines are not too obscure from our reach, and may be the future of space-exploration. They don’t break any laws of physics (contrary to faster-than-light travel), and are significantly easier to construct than other proposed spacecrafts like generation ships. Modern 3D-printers are already capable of operating in zero gravity, and we are on the verge of artificial intelligence. A few more advances in nanotechnology and the development of a nuclear fusion drive could have us sending these probes as soon as by the end of the 21st century. 


How do these machines relate to extraterrestrial life, you ask? In short, if alien life exists in our galaxy, we should’ve already seen these probes in our own solar system or neighbouring systems. Unless we are mere animals in a zoo to some higher-dimensional beings, there is good cause for intelligent lifeforms to engineer such machinations. In addition to exploration, they can be modified to seed habitable planets (spreading the host organism), terraform impossibly tall mountains to lush forests, or, become the American government and direct destructive projectiles to attack inhabitants in the name of oil.


With such profound reasons (arguably except the latter one) to construct these devices, the only other possible explanation is time. Maybe the galaxy is just so incomprehensibly large that it would take billions of years before any aliens could make a touchdown? 


While this could be potential evidence, it’s not evidence of the lack of von Neumann probes, but rather evidence of not comprehending the universe’s age and scale.


Let me demonstrate. In a hypothetical future where we have launched Neumann probes, these probes would be outfitted with forms of engines (such as fusion drives) capable of achieving speeds higher than 10% of the speed of light. In this hypothetical future, we would assume (or, underestimate) that it would take 500 years for a singular probe to reproduce itself upon touchdown on a planet or asteroid, and that each subsequent probe would be sent 10 light years away before touching down. Taking all this into our calculations, it would only take a few hundred million years, tops, to fully explore the Milky Way (which, as a reminder, contains tens of billions of habitable planets).


You might be thinking, ‘A few hundred million years? Does this guy know what the word “only” means?’  While a hundred million years is far longer than the history (and at the rate of global warming, the future) of homo sapiens, it is a mere blink of an eye at the cosmic scale. The universe is over 14 billion years (14,000,000,000) old, making the time it would take for Neumann probes to fully explore space insignificant. If intelligent alien life did exist, there were some 13 billion years for potential civilizations to develop and evolve, so it is very unlikely that they haven’t reached the levels of Neumann probes yet.


With all the means and motives to do so, why haven’t Neumann machines been built and arrived? Moreover, this is only on the simpler side of theoretical advanced machinates; the tip of the iceberg. With up to billions of years to advance, intelligent lifeforms should’ve been able to build Dyson spheres, faster than light vehicles, other machinations capable of warping space-time, you name it. Yet, with numerous advanced observational facilities and experts all over the world, nothing out of the ordinary has been detected. 


At the end of the day, the debate of extraterrestrial intelligent life is based on conjectures, observations, and the hope to not be truly alone in this universe. Although the lack of advanced technology like Neumann probes amongst other things make the existence of other intelligent life unlikely in our current understanding, the possibilities are endless. Perhaps Neumann probes have been sent, but have remained utterly undetected. Perhaps in a faraway Cybertron, Optimus Prime and his Autobots are observing us as we speak. Perhaps, we are the descendants of these very probes sent billions of years ago that introduced the earliest forms of bacteria to our Earth. 


After all, who am I to spoil the fun? What good is high school if you can’t dream away, about aliens on a distant planet; the new iPhone; just pretty much anything and everything but that upcoming exam. 

Photo: Tengyart on Unsplash.com