Self-replicating probes are imminent – implications for SETI

Abstract

In the early 1980s, the Sagan-Tipler debate raged regarding the interpretation of the Fermi paradox but no clear winner emerged. Sagan favoured the existence of ETI on the basis of the Copernican principle and Tipler favoured the non-existence of ETI on the basis of the Occam's razor principle. Tipler's stance was an expansion of the similar but earlier Hart declaration. However, crucial to the Tipler argument was the role played by self-replicating interstellar robot probes. Any technologically capable species will develop self-replication technology as the most economical means of exploring space and the Galaxy as a whole with minimal investment. There is no evidence of such probes in our solar system including the asteroid belt, ergo, ETI do not exist. This is a powerful and cogent argument. Counter-arguments have been weak including Sagan's sociological explanations. We present a Copernican argument that ETI do not exist – humans are developing self-replication technology today. We are developing the ability to 3D print entire robotic machines from extraterrestrial resources including electric motors and electronics as part of a general in-situ resource utilization (ISRU) capability. We have 3D-printed electric motors which can be potentially leveraged from extraterrestrial material that should be available in every star system. From a similar range of materials, we have identified a means to 3D print neural network circuitry. From our industrial ecology, self-replicating machines and indeed universal constructors are feasible. We describe in some detail how a self-replicating interstellar spacecraft may be constricted from asteroidal resources. We describe technological signatures of the processing of asteroidal material (which is expected to be common to most star systems), and the excess production of certain types of clay and other detritus materials. Self-replication technology is under development and imminent – if humans are pursuing self-replication technology, then by the Copernican principle, so would any technologically savvy species elsewhere. There is no evidence that they have.

Lotka–Volterra models for extraterrestrial self-replicating probes

“…In any case, it does seem that based on our work and that of [ 23 ], mutated probes cannot explain the Fermi paradox. Instead, one is faced with the possibility that the lack of SRPs might indicate that highly advanced extraterrestrial civilizations do not exist [ 32 ]. Another possibility is that the probes are around, we just have not detected them [ 12 , 33 ].…”

The prospect of von neumann probes and the implications for the sagan-tipler debate

“…While Matloff (2022) considers several motives for self-replicating probes, Ellery (2022a) suggests that self-replicating machines (and probes) are an inevitable economic development in offering a low capital cost approach to any venture by virtue of their exponential productivity – Galactic colonization in 24 generations over ~1 million years or so at the cost of only one or two probes. Each self-replicating probe at its target destination would manufacture a maximum of 48 offspring over this period.…”

“…While Matloff (2022) considers a range of locations for lurking self-replicating probes, Ellery (2022a) suggests that technosignatures of industrial activity might be found amongst asteroids. He examines in detail how a self-replicating probe might be manufactured by exploiting 3D printing technology in conjunction with methods being developed for in-situ resource utilisation for asteroids subject to severe closure conditions.…”

“…Nevertheless, extensive deposits of clays on asteroids would constitute a readily identifiable technosignature. Ellery (2022a) then considers how the self-replication scheme could construct an interstellar propulsion system. The self-replicating probe must be robust enough to survive its flight to the nearest star – on average 5 light years distant if we assume our own solar neighbourhood stellar density.…”

“…If we can muster 0.1c interstellar transit speeds - consistent with the Daedalus starship (Bond et al 1978) - the flight duration is 50 years rather 100s-1000s of years. Focussing on beamed propulsion methods using large area sails, Ellery (2022a) considers that the scale of interstellar propulsion requires self-replication of modular units to achieve such enormous scales. Free electron lasers are high-power vacuum tube technologies that can be focused by a large area Fresnel zone lens to propel a lightsail augmented by electric and magnetic sailing.…”