When facing the Fermi paradox , one of the most challenging questions to answer is why exponential expansion technology has not yet taken over the entire universe. This self-replicating group of alien robots is often called the " von Neumann detector", and this idea has been the main content of science fiction for decades. But so far, there is no evidence that they exist outside the realm of science fiction. Perhaps, this may be because we did not spend a lot of time searching for them, and this situation may change with the further application of the new five-hundred-meter aperture spherical radio telescope (FAST). According to some recent calculations, this huge new observation platform may be able to detect the "Von Neumann probe" group relatively far from the sun.
These calculations were performed by Dr. Zaza Osmanov of the Free University of Tbilisi, Georgia. The results show that in the radio spectrum band where the focus of FAST is located, a group of highly advanced civilization "von Neumann detectors" can be seen. To help find and search, Dr. Osmanov used two frameworks to define potential solutions. The first is the idea of the Kardashev ( Kardashev) civilization; the other is the estimation of the distribution of heat and electromagnetic radiation of any such group.
"Kardashev scale" is an easy-to-understand concept in scientific speculation. It focuses on the overall energy use of a civilization, and different milestones (Type I, Type II, or Type III) are respectively related to the utilization of the entire energy output of planets, stars, and galaxies. At present, human civilization is considered to be around 0.75 of the Kardashev standard.
But considering the relatively limited time for humans to develop on this planet, if life exists elsewhere in the galaxy of , it is likely to have a longer time to evolve and develop technology.The longer the technological development, the greater the possibility that civilization will reach the development level of K-II (stellar energy) or even K-III (galaxy energy).
Above: Graphical description of the Kardashev scale and the related power consumption level.
When a civilization has so much time to research new technologies, it is likely that it has developed the ability to create self-replicating machines, such as the "von Neumann detector", as part of the technological development process. Once the tech cat is taken out, it is almost impossible to put it back. Even if a civilization releases them into the galaxy, self-replicators will likely start to expand to every available resource, and will only focus on its own reproduction.
However, according to Dr. Zaza Osmanov, we can at least see any such path to destruction. Like all imperfect systems, these self-replicating machines emit some form of radiation. After some simplified assumptions, Dr. Osmanov calculated that these radiations should be visible in the radio spectrum. Specifically, it will fall right in the middle of the spectrum that FAST is designed to pick up.
However, knowing that it is possible to detect a swarm is only a little help, knowing how far away you can detect it is even more useful. Just like potentially dangerous asteroids, the sooner we are aware of impending doom, the better (at least to fight it). In order to calculate these distances, Osmanov made some more simplified assumptions, such as the maximum power output that can be expected based on the level reached by the Kardashev civilization. For example, the "Von Neumann" star cluster of Type II civilization does not emit more light than its entire energy utilization level.
With these additional assumptions, Dr. Osmanov discovered that FAST may detect the self-replicating robot groups of Type II and Type III civilizations. Considering the expected sensitivity of the FAST instrument, it should be able to find any type II civilization galaxy group within about 16,000 light-years, which means that any type II civilization detector can be seen within the nearest 15% of the Milky Way. . On the other hand, the bee colony created by Type III civilization,It may be detected in the range of 400 million light-years, which includes most "nearby" galaxies.
Above: the false von Neumann probe, which is a self-replicating probes (Self-replicating probes), designed to use any resources found in the star system Make self-replication and explore the universe.
So far, Dr. Osmanov’s papers have only been published on arXiv and seem to have not been accepted by academic journals, which means that these calculations have not been peer-reviewed. However, they still provide an interesting thought experiment and point out potential detection mechanisms for some black swan-like events.
Although, now we know that FAST can detect threats before they reach the earth, which is really gratifying, but the question is what happens if we can't find any danger? What does this mean for our place in the universe or the development of self-replication technology?
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