A Metallurgist's Skepticism on Self-Replicating Probes and the Fermi Paradox
A metallurgist's doubts about self-replicating probes
As a metallurgist, I argue that self-replicating probes face insurmountable hurdles in asteroid mining and materials science. Without gravity, water, or an industrial hinterland, concentrating raw elements and maintaining precision components over millennia is thermodynamically improbable. These process-chain limitations, not physics, likely explain the silence of the galaxy.
My suspicion is that von Neumann probes are constrained not by the laws of physics but by process-chain closure and materials aging — both, at root, thermodynamic limits.
- zeryx
I studied material science in school specifically to try and address his concerns. Unfortunately they are all quite valid - the hard part isn't manufacturing, extruding, printing. Those are actually all quite reasonable (albeit not super space or weight efficient).
The hard part is refining and ore enrichment, and most techniques that could possibly work in microgravity are almost impossible to test on earth. You would certainly need vitamins for electronics components for a time. Even much older computer chip architectures (1990s level) still require the clean room and 20-30 stages of prep. I believe an orbital chip fab is not only possible but, kind of ideal? Keeping it clean would be within reach - and it's mostly if not entirely an autonomous process from silicon monocrystal to assembled part today.
We're along way from self replicating probes. But I would argue were quite capable of autonomous mining, manufacturing and material transport - assuming we can figure out how to refine effectively. If someone wants a cool PhD project and ship an experiment to the ISS, I would argue an ionic or plasma based refining technique designed for micro gravity could be very interesting and very useful
- seiferteric
Wouldn't a counter this argument be biological systems? These are reasonable points as long as we are talking about current methods, but I assume if we were to get to the point of self replicating probes it would be done by something like nanotechnology, synthetic biology like systems.
- bryanlarsen
If an elderly but distinguished scientist says that something is possible, he is almost certainly right; but if he says that it is impossible, he is very probably wrong.
- Arthur C Clarke
- marcosdumay
Yes, we don't know how to make a half-ton replicating probe right now.
No, none of the arguments on the article have any implication on the possibility of such a probe. None at all.
There's something to look into at the durability argument. The article has no usable information on it, and it's probably not a showstopper. But again, the only thing on the article is that yes, we don't know how to make one such probe right now.
- chrisshroba
This article contains 19 em-dashes, as well as the following direct quotes:
Not X, but dramatic Y:
- "But the missing few percent are not marginal; they are precisely the hardest items"
- "is not an engineering detail. It may be the entire problem.
- "the galaxy may be quiet not because nobody tried, but because replication is harder than arithmetic suggests."
as well as at least two other longer "not X, it's Y" type phrases.
Also, melodramatic phrasing like "Replication must outrun degradation — and degradation never sleeps."
Yes, someone could have written these manually, but these particular patterns are the things I notice most commonly in LLM outputs that I don't see in known-human writing.