Where are All the von Neumann Probes?

You cannot explain the Fermi Paradox, or the absence of evidence of alien life in the universe, without accounting for von Neumann probes. A von Neumann probe, first proposed by mathematical genius John von Neumann in 1948, is the idea of a self-replicating machine—a machine that can make potentially infinite copies of itself. In the future, it seems conceivable (perhaps inevitable) that, if technology advances long enough, we will eventually create such self-replicating machines in the form of spacecraft and use them to populate the galaxy and ultimately, the entire universe.

Space travel for humans is extraordinarily difficult. We evolved to live on earth for an average lifespan of about 80 years. We require oxygen, water, food, which all take up valuable space and resources. Not only is it difficult (and expensive) to leave the atmosphere and get into space, once there, there’s no air, food, or water. Plus, space is so large that it would take hundreds of thousands of years to travel between just two stars of trillions.

Using robots for space exploration makes much more sense, especially in the future when robots will be better and smarter than humans in every way. We will likely use von Neumann probes for space travel, which could be made with nanotechnology to be smaller than a pin head, and send billions of these probes into space in all directions. Many will be destroyed, but some will land on planets, and some planets will be habitable, in which case the self-replicating machines will self-replicate and make more von Neumann probes to further expand and colonize more planets in more galaxies throughout the universe.

If we can potentially do this one day—and there’s nothing in the laws of physics that says we can’t—then conceivably some other alien civilization could have done this in the past. The universe is a lot older than earth. Another planet in this or another galaxy could have developed a technological civilization millions of years ago, in which case they should have invented von Neumann probes by now. If they did, the galaxy should be completely populated by von Neumann probes, yet we see no sign of them.

Does it mean that von Neumann probes are impossible to create? I don’t see why not. It’s more likely that a technological civilization will inevitably destroy itself before advancing far enough to create von Neumann probes. That would mean our civilization is almost certainly doomed in the near future.

This is why the Fermi Paradox is so frightening. The fact that we see no von Neumann probes means we will probably never create them. And the only reason I could envision no one in the entire future of human civilization inventing von Neumann probes is because human civilization goes extinct before anyone invents the technology to do so.

Unless… there are/were von Neumann probes in our galaxy, but we just haven’t detected them yet.

What if we—all life on earth—are the result of von Neumann probes from an alien civilization billions of years ago?
I’ll explore that possibility in my next post.