This seems enormously optimistic to me, both as a technological assertion and a cultural one. Like even if we could build self-assembling nano-machines (nota bene: we can't even build self assembling macroscopic machines) why would we use them to disassemble the moon? I mean a 0.1 % chance, maybe. But 10% chance? Nuts.

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ben_w 5 days ago | parent [-]

Culturally? Nuts, sure, but you've been following the news right? Humans are nuts.

> we can't even build self assembling macroscopic machines

TRL-1 tends to imply such statements :)

… although, is that actually true? For macroscopic, I mean? Given factories exist and robot arms are part of them, are you sure nobody has used a robot arm to assemble an identical robot arm from a pile of robot arm parts? I've not heard of anyone actually doing so, but are you sure that's never been done?

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nathan_compton 5 days ago | parent [-]

Essentially, completely sure. Also, purely energetically, disassembling the moon basically could not occur on the timescale of a few years.

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ben_w 5 days ago | parent [-]

Energetically, it would take 1.244e29 J to disassemble the moon: https://www.wolframalpha.com/input?i=binding+energy+moon

This can only be done if the VN machines are able to form a useful cloud away from the moon immediately after they've disassembled the surface layer. If they aren't allowed to do that, it would take 415 millennia: https://www.wolframalpha.com/input?i=1.244e29+J+%2F+%281kW%2...

But you can make it twice as fast by getting the first layer to lift the second layer to cislunar orbit, then combine the power of both layers; then four times as fast etc. etc.

I don't know the upper limit before the main constraint is cooling.

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nathan_compton 5 days ago | parent [-]

Without getting into hairy calculations, if you really thought this was possible with a high probability, you'd accept $20 bucks and agree to give me a big payout (say $4000) in the future (say when you retire) because you think there is a large chance you'd never have to pay.

We could game this out and figure out exactly what a rational bet is, but you get my point. It seems very hard to believe you think there is a 10-15% chance. Those are probabilities at which you would be making major moves to hedge.

	▲	ben_w 5 days ago \| parent [-]
		I do not understand how you think those numbers work. I said "10-15%" of the moon being disassembled in my (current natural) lifetime, as in the break-even point for a bet is me spending $20 today for a chance you pay me $133-$200 on my deathbed. (I don't expect you to want to do that just because your odds for this are even lower, so you'd only want to take the other side of a 1:10 payout ratio if you thought it was 90% likely to be disassembled, the point is the breakeven point for positive expected returns is return ≥ cost * probability even before time discounted value of money and why would I want more money when I die). As for hedging, isn't that normally done for negative outcomes? If so, what's the downside here? A VN replicator on the moon is unambiguously harder than one on Earth (existence proof: life only found on one of them), so if the D6-to-D10 dice roll says "success!" for the moon, the mere existence of the tech will also radically transform what money even means down here on earth. Surely the hedge to make against it is what to expect if we don't maintain the current rate of tech development that makes such an outcome even this likely? And the hedge for that looks somewhere between "prepper" and "political economist"?