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A metallurgist's doubts about self-replicating probes

centauri-dreams.org

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Re: A metallurgist's doubts about self-replicating probes

#61

Post by malfist »

credit_guy wrote: post #6

> Shrinking that into a 500 kg seed — or even Freitas’ original 100-ton seed — is not an engineering detail. It may be the entire problem. How many AI tells can you count there? But honestly (see what I did there?) the AI slop is reasonably cleaned up in this piece. However, the essence of the argument has two deep flaws. One is that the time to complete an interstellar voyage is extremely long and you need some exer…

The subheadings are all full of AI tells.

> The closure problem, honestly accounted

> A thermodynamic framing

All of those read like AI, especially considering that the subsections aren't consistent. Some are numbers, some are not, some are framings some are problem juxtapositions.

EM dashes everywhere, AI tells in subheadings, "It's not X it's Y" all over the text of the body. This is clearly AI writen.

Notice also the article has two by lines. At the top it's "by Paul Gilster" at the top of the text it's "by Peter Marinko"

Also note that the "metallugrist" they're interviewing that they claim "his current work explores the thermodynamics of technological civilizations" at Uppsala University, but the university's page for him says he's only involved in Animal Research Ethics Committee

Re: A metallurgist's doubts about self-replicating probes

#62

Post by credit_guy »

JohnMakin wrote: post #34
credit_guy wrote: post #13

Earlier quoted context omitted.

That is true. What should we conclude from this statement?

That you shouldn’t assume just because in the past ideas have existed that became reality, that all current ideas are feasible or possible?

I didn’t assume that. The author makes the opposite assumption: that because nobody has ever proposed a path to technological feasibility, that thing will forever be technologically unfeasible. I simply find this argument to be very weak.

Re: A metallurgist's doubts about self-replicating probes

#64

Post by asdff »

M95D wrote: post #51
qnleigh wrote: post #48

Earlier quoted context omitted.

I would also think that self-replicating probes would work more like living things. He seems to be imagining that we make probes like modern machines, and then find ways to let them build themselves. But nature found much easier solutions.

Life as we know it until now has big difficulties outside goldilocks zone. It would theoretically be possible to make microbes (or fish?) that float high in Venus atmosphere, if we put money into 200 years of research, but no way life as we know it could ever break up and "eat" an asteroid.

Never say never

https://en.wikipedia.org/wiki/Endolith

Re: A metallurgist's doubts about self-replicating probes

#66

Post by neaden »

Animats wrote: post #40
zeryx wrote: post #2

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 wou…

> Every terrestrial concentration process relies on things an asteroid lacks: gravity-driven sedimentation, water-based flotation, density separation in fluids, atmospheric combustion. That's a good point. Most bulk industrial processes won't work in zero G. This limits asteroid mining. Breaking off pieces of rock and accelerating them to somewhere, maybe. Building a big wheel and spinning it up to get some gravity,…

"Israel or North Korea, both of which try to be self-sufficient" - Neither of them do any such thing though. From a quick search Israel imports about 80% of their calories though they also export some food they are heavily reliant on imported grains and meat. North Korea is obviously harder to get information on but it imports large amounts of food from China.

Re: A metallurgist's doubts about self-replicating probes

#67

Post by neaden »

bryanlarsen wrote: post #8

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

OK, so elderly distinguished scientists say it is impossible for me to travel FTL by spinning in a circle with my eyes closed while on acid, guess we should start investing research dollars into that.

Re: A metallurgist's doubts about self-replicating probes

#68

Post by bilsbie »

I find the confusion confusing. Meaning isn’t it obvious it would take an entire civilization and all of its technology to create functional space craft, computers, and mining robots?

I don’t see how anyone would expect some kind of self contained probe to be able to do all of that.

Re: A metallurgist's doubts about self-replicating probes

#69

Post by asdff »

pfortuny wrote: post #32
marcosdumay wrote: post #27

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 ri…

The self-replication assumes also that there is enough energy stored in each planet (or coming from a Sun) to do the work... That is pretty much unlikely.

Any chemical bond is a potential source of energy. Plenty of sources of potential energy too able to be converted to work.

Re: A metallurgist's doubts about self-replicating probes

#70

Post by giantrobot »

Animats wrote: post #40
zeryx wrote: post #2

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 wou…

> Every terrestrial concentration process relies on things an asteroid lacks: gravity-driven sedimentation, water-based flotation, density separation in fluids, atmospheric combustion. That's a good point. Most bulk industrial processes won't work in zero G. This limits asteroid mining. Breaking off pieces of rock and accelerating them to somewhere, maybe. Building a big wheel and spinning it up to get some gravity,…

Both North Korea and Israel are notable (compared to space) for their dense oxygen rich atmospheres, accessible large reservoirs of water, access to solvents/lubricants, and a generally "shirt sleeves" environment for workers. Asteroids, the Moon, and deep space don't really have these things. So you're not just bootstrapping an industrial facility at those locations but all the basic infrastructure that industry requires to exist.

With space manufacturing the first widget out of a factory costs trillions of dollars. There's also few if any raw materials that are far more abundant in space than here on Earth (at orders of magnitude smaller cost).

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