John von Neumann introduced the world to his revolutionary idea for a species of self-replicatingrobots. The word "universal assemblers" is used. Researchers involved in the Search for Extraterrestrial Intelligence adopted the idea that self-replicating probes would be an effective way to explore the universe. Veon Neumann probes are considered to be a viable indication of technologically advanced species.
It is likely that Von Neumann probes will be deployed soon, and the range of applications is endless. What about the consequences? The potential harm that Von Neumann probes could have was explored in a recent study by a professor. There is a chance of runaway population growth and how a series of biologically-inspired controls would prevent that.
The Canada Research Chair in Space Robotics & Space Technology is held by Professor Ellery. A paper about Curbing the fruitfulness of self-replicating machines was published in the International Journal of Astrobiology. The purpose of the study was to investigate how Von Neumann probes could explore the universe safely.
The Von Neumann probes and their implications for space exploration and SETI is a topic that Ellery is well versed in. While Von Neumann was interested in self-replicating machines as a means of advancement, the concept was quickly seized upon by researchers engaged in the Search for Extraterrestrial Intelligence. The idea of machines was used by Frank Tipler to argue that intelligent life did not exist outside of Earth.
The assumed likelihood of intelligent life in the universe stands in contrast to the lack of evidence for it, according to this argument. According to Tipler, an advanced intelligence that preceded humans would have created Von Neumann probes long ago to explore and colonize the galaxy and have plenty of time to do it. He stated in his first paper that extraterrestrial intelligent beings do not exist.
“I shall assume that such a species will eventually develop a self-replicating universal constructor with intelligence comparable to the human level – such a machine should be developed within a century, according to the experts – and such a machine combined with present-day rocket technology would make it possible to explore and/or colonize the Galaxy in less than 300 million years.”
We must assume that no intelligent civilizations exist because we see no evidence of self-replicating machines in our universe. Carl Sagan and William Newman responded to the conclusions in a paper. The absence of evidence is not the evidence of absence according to the author. Ellery was studying in the UK at the time and was influenced by this debate. He wrote to Universe Today.
“When I was at the university of Sussex doing the masters in astronomy, I came across the Von Neumann probe concept. And that completely captivated my imagination and I decided then to shift to engineering and space robotics. Basically, I was trying to figure out how I could start to work on Von Neumann probes, eventually. After my PhD, I spent a couple years in working in a hospital as a medical physicist and in industry for a bit, and then came back to academia.”
In the past, Ellery's work has been focused on space robotics, with planetary rovers for Martian exploration and other aspects. The Astrobiology community is dedicated to finding extraterrestrial life on Mars and beyond. It was only a few years ago that research programs allowed him to work on the idea of self-replicating machines.
The study considers self-replicatingrobots as a means of building infrastructure on the Moon but has applications far beyond that.
“I started moving away from the rovers and more into the In-Situ Resource Utilization [ISRU] side of things. You know, mining the moon and that sort of sort of stuff. I was actually doing some work in 3D printing as a mechanism to, uh, leverage resources from the Moon. So one of the things we’ve done is we’ve 3d printed an electric motor. This is a major step towards realizing 3d printing, robotic machines on the moon using Luna resources.
“The primary motivation in the back of my mind was I’m doing this to try and build a self replicating machine.And so in a way, it’s come full circle to my original interest in using self replicating machines to explore the cosmos, and its implications for the SETI program, for the Fermi Paradox, and so on, which originally was what motivated down me down this road.”
Issues that need to be discussed prior to technological advancement and humanity's future in space are obvious. There is a question of if self-replicating machines will grow beyond our control. The result would be disastrous if some malfunctioned and began consuming everything in their environment. The "grey goo" scenario is a speculative possibility.
K. Eric Drexler came up with the term "grey goo" In his 1986 book, Engines of Creation, he poses a thought experiment that could lead to an ecological catastrophe. It was described by Drexler.
“[E]arly assembler-based replicators could beat the most advanced modern organisms. ‘Plants’ with ‘leaves’ no more efficient than today’s solar cells could out-compete real plants, crowding the biosphere with an inedible foliage. Tough, omnivorous ‘bacteria’ could out-compete real bacteria: they could spread like blowing pollen, replicate swiftly, and reduce the biosphere to dust in a matter of days. Dangerous replicators could easily be too tough, small, and rapidly spreading to stop – at least if we made no preparation. We have trouble enough controlling viruses and fruit flies.”
He felt the scenario needed to be taken seriously despite Drexler dismissing it. He stated in his book that this thought experiment made it clear that humans cannot afford accidents with replicating assemblers. There is a theory that machines could run amok and become hostile to life.
According to Drexler, the "grey goo" scenario is more about perception than reality. He agrees that it's a possibility that warrants discussion and action to make sure worst-case scenarios can be avoided. He put it that way.
“It’s an idea more than anything else. I’m not convinced of how realistic it is. The problem is, it’s the commonest question, ‘what do you about uncontrolled self-replication?’ Because people imagine a self-replicating machine to be like a virus, and it will spread. Which it could do, but only so far as there are resources available.
“[T]he thing that we have to be cognizant of is that self-replicate machines sound scary. We have to be aware that some people have knowledge and they can temper that knowledge, and so can appreciate rational argument. Other people are more focused on the fear, rather than the probability. But the idea behind this is being able to curb the self-replication process is to try and show that we are working on that problem – that we’re not just going straight into this self-replicate machine without thinking about the potential consequences.”
It is incumbent upon us to develop preventative measures to make sure Von Neumann probes behave themselves before we begin experimenting. He suggests a solution based on cellular biology.
The Hayflick Limit is a concept in biology that states that a normal human cell can only divide and replicate 40 to 60 times before it breaks down. The limit is imposed by the protective caps at the ends of the DNA strands inside the cell's nucleus. Thanks to growing interest in anti-aging treatments, telomere research has advanced a lot.
The machines that are part of the proposal are similar to chromosomes and contain genetic memory. The modules are made up of a volumetric array of magnetic core memory cells that are programmed with zeros and one's. The instructions will be copied into every machine by the parent machine.
The linear tail of blank memory cells that feed into the original to-be- read memory array is constituted by the telomeres. An artificial Hayflick Limit is imposed by the number of these cells. He described the process.
The point at which you start copying an array is defined. A blank magnetic core is used to copy each one from one to another. When you copy it, you move on to the next one, and then you start copying at the next point. You don't copy at the point where you are sitting.
When you start copying, you lose the first generation, and then the second generation, and then you start copying again. You can only copy on the next square if you are not copying the first position. You are cutting out data.
“Now the, in order to retain the information in that block, you can add a tail of units. And so basically it copies each unit along the tail, and it’s basically not copying the first one that lands on. So every generation is basically you get, you lose one cell of memory. So that first tale doesn’t actually code for anything. It’s just basically a telomere. So you just basically plan how many generations you need, [which] defines how long your tail is.”
The industrialization of the moon is one of the applications explored by Ellery. The infrastructure necessary for human habitation, as well as more copies of themselves, are manufactured by the robots using 3D printing and in-situ resource utilization. It would allow for a long-term human presence on the Moon, in line with the goals of NASA, the Chinese and Russian space agencies.
The main goal of the Artemis Program is to create a sustained program of lunar exploration. One of the main benefits of self-replicating machines is their ability to develop lunar and other resources. It was said by Ellery.
“When we go to the Moon, we have two choices. At the moment, the interest is in going to the moon and mining water, and then separating the hydrogen and oxygen, then burning it as propellant. To me, that is wasteful. That’s not sustainable because you’re taking a scarce resource and then you’re burning it, much like we’ve done on our Earth. Why are we taking all our bad habits with us?
“The other approach, of course, is to look at resources and work within the limits of those resources. So, if you look at minerals. Minerals are widespread: common rock-forming minerals on the Moon and asteroids. Basically, we would be sending these probes to the Moon and other locations in the Solar System, wherever we’re intending to [build bases]. They’re tectonically dead, they’re just hunks of rock. So I see nothing wrong with utilizing those resources.”
Beyond the Moon, Mars, and asteroid mining, there is the potential for terraforming operations. By any stretch of the imagination, the last but not least is the possibility of settlement of exoplanets. This will have implications where the whole SETI vs METI is concerned.
“These Von Neumann probes potentially act as Scouts. They’re scouting vehicles to investigate target locations before humans go there. So, of course, it makes no sense to send out a World Ship from here to another stellar system that you’ve never been to. You have no idea what’s there. You want to send robotic machines out there first to give you information. So you understand what the implications are, what you need to take with you, what resources you need, and what resources you don’t need.
“Self-replicating probes are the mechanism for doing any kind of interstellar space exploration, whichever way you want to look at it. You will always use these to try and scout beforehand and to send information, if only to locate other planets that are Earthlike, which are no use, or which ones might be of use (that you could adapt to). And perhaps most important would be to find out if there is intelligent life and does it present a threat. You send a Von Neumann probe to a planet, and the civilization doesn’t know where it comes from. You send signals, they know exactly where the signal is coming from.”
Given how humanity finds itself on the verge of another space age, these and other considerations are very important. There are many safety, legal, logistical, and ethical considerations that need to be worked out in advance of a plan to return to the moon. There are certain risks that come with technological revolutions and the possibility of First Contact.
If we plan to use self-replicating probes to pave the way for human settlement, we need to make sure that they won't consume everything in sight. If these probes are to be used as scouts, explorers and ambassadors to extraterrestrial civilization, this is even more true. It's an elegant solution to make "programmed cell death" a part of their designs. If an extraterrestrial civilization is already exploring the universe with Von Neumann probes, we can only hope that they took the necessary precautions.
There is further reading on Cambridge University.
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