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[Trekkin]

It's not as if the asteroids don't contain ice which can be used to create rocket fuel on-site to get back home.

Works great in Kerbal Space Program, I grant you, but LH2/LOX has significant cryogenic boiloff problems at these distances, to say nothing of hydrogen's propensity to simply leak through metal. Having to carry along zero boiloff hydrogen tanks as well as the additional power generation capacity to run the electrolyzer adds to mass, and everything in space has a limited lifetime before micrometeroid impacts sandblast it into uselessness so we can't amortize the additional launch costs indefinitely.

It's well within the realm of possibility given significant improvements to liquid fuel handling, but the technical obstacles to ISRU are formidable.

[Parsely]

Relevant Isaac Arthur video.

He argues that we have plenty of rock on Earth, and therefore if Earthnoids import metals it would be in a refined form, not as raw ore (except maybe in early days when you might need to bring it to a moon or LEO for refining ops). His argument shows up around 9:24 in the video. He also talks about profit and legality.

[RadtheCad]

Exactly the one I mean (with realisation I hadn't recalled it perfectly, but good enough to know that it is the one I meant).

qntm.org's a gem.  You should read Ra if you haven't already.

[Gentlefish]

I quite like how all the talk is "We can't do it now so it probably won't be feasible in the future". I'm not saying let's get on it right this second that's crazy.

But the fantastic surplus of earth-rare metals and glut of even common earth metals means it's a resource which shouldn't be overlook, especially considering that by doing so will help conservation efforts in every location where we mine (read: everywhere)

[smjjames]

Relevant Isaac Arthur video.

He argues that we have plenty of rock on Earth, and therefore if Earthnoids import metals it would be in a refined form, not as raw ore (except maybe in early days when you might need to bring it to a moon or LEO for refining ops). His argument shows up around 9:24 in the video. He also talks about profit and legality.

Even if it's in refined form (which would be more likely since it's a step that they can do on site or in Earth Orbit), they still have to get it down to the surface somehow. Most sci-fi methods either involve a transatmospheric craft that can land and take off on it's own power (whether a freighter landing or smaller transport shuttles going from orbit and back) or some kind of capture mechanism (whether guiding down the ship or grabbing the cargo itself). Space elevators are another option too.

Transatmospheric craft would be the most viable with today's technology and arguably the easiest and safest way to do it.

I quite like how all the talk is "We can't do it now so it probably won't be feasible in the future". I'm not saying let's get on it right this second that's crazy.

But the fantastic surplus of earth-rare metals and glut of even common earth metals means it's a resource which shouldn't be overlook, especially considering that by doing so will help conservation efforts in every location where we mine (read: everywhere)

Oh definetly, though it'll take time and better technology before it happens. Right now though, it's not too hard to send a testbed mining rig up there, so, I wouldn't be surprised if there were at least a few projects in the works somewhere to do something like that.

[Gentlefish]

There is at least one business actively looking into getting up there as we speak.

Of course it is based in good ol' capitalistic US of A

[Trekkin]

There is at least one business actively looking into getting up there as we speak.

You mean Planetary Resources? They're not doing too well.

[Starver]

The main advantage (apart from any advantages to microgravity processing in, say, the crystal-growth stages and solar-powering absent diurnal cycles/weather, but likely need to centrifuge or get around the Earth-type slag-floating stages usually practiced in a ore refinement) is getting masses of product together intended for use outside the depths of Earth's gravity well. Delta-Vs needed to get to LEO from the asteroid belt might be not insignificant or without other issues, but it might yet compare well to trying to ground-launch such large things (and maybe not massive, if mostly framework, but certainly difficult to fairing-up to punch out through the atmosphere atop a BDR), and the further out of the well your site-customer wants the modules then the more the equation swings towards out-sourced manufacture against terran-factories and upwards deliveries.

Once you have bootstrapped the off-world manufacturing base from the first-of-the-last upward-bound componemts, maybe...

[Trekkin]

Yeah, that's kind of the perennial problem with space manufacturing: once you have something you need in space, a number of industries become viable to move to space to more economically supply that thing, but it's difficult to find something that it's economically favorable to manufacture in space in the first place.

[smjjames]

It's also partly a demand problem, the only 'demand' are the astronauts on the space station, but in all, it's really a bootstrapping problem because you have to get the first bits started.

[Reelya]

Regarding the simulation bit, you don't need to simulate this universe. Hell, I'd say that any self-simulation will be inherently larger/slower; otherwise you have some serious fundamental issues with notions of computing, because you'd get improvements through self-simulation resulting in infinite improvement.

The key is to not simulate our universe, but to simulate a universe which occupies a complexity class that can be simulated from our own universe in some sub-linear form. Remember, our universe is BQP. Strip out quantum physics and we're squarely in P. We know, naturally, that P is a strict subset of BQP (Shor's algorithm, etc.); all that we have to do is properly constrain this hypothetical universe such that it maximizes the power that BQP has over P. Should be easy to make it sub-linear that way.

In short, simulating our universe from within our universe is stupid because self-simulation is not sub-linear in performance and size. Rather, we need to simulate universes that occupy a lower complexity class than our current universe. Only then is it feasible.

From that point of view it could be argued that things like the uncertainty principle and seeming quantum randomness could in fact be simulation short-cuts that we weren't meant to notice. The uncertainty principle links pairs of variables together. That could just be because they're like floating point numbers which share the same information-space for two separate things, shifting the data-space around based on which one matters at that moment.

The same with the quantum observer effect. Things act differently if you look too closely. That could be because of some unknown quantum-woo effect or it could be a byproduct of lazy simulation all the same. Wave/particle duality could just be because if things aren't closely observed by other particles they are modeled as a probability-function (which we inside the simulation interpret as "waves"), which allows you to skimp on modeling completely, but if they're looked at, you need to decide where in the probability they actually are.

And if you think about it, the wave/particle duality and observer effect is a paradox. If the laws of physics are correct, then no particle can be "not observed" for any measurable length of time, since the forces of nature should be operating all the time: electromagnetic, weak, strong and gravity forces should constantly be tugging at all fellow particles, thus mean they're always observed and cannot ever be a "wave". So, there has to be some cut-off below which they're just actively ignoring physical forces or approximating them in a static way. Otherwise, they'd constantly have their waveforms collapsed due to graviton interference.

[Il Palazzo]

snip

snip

http://www.smbc-comics.com/comic/2012-02-29

[KittyTac]

I'm pretty sure that the universe "stack" is not a stack, but rather a tree. There is nothing stopping a civilization from creating multiple simulations.

[wierd]

A better way to put it, is that a universe that has systemic inconsistency, would not be able to reliably sustain a consistent simulation. (as the systemic inconsistency would be, naturally, systemic)

Now, things can be fully consistent, and not be quantum.  The existence of discrete quanta suggests some level of complexity has been removed, for ease of computation.

[Max™]

There is a lot of room down at the bottom end of the time distance scales which nobody would ever notice if it was trimmed. It's one of the first areas you trim to reasonably simulate a volume of spacetime anyways, as long as the behavior expected is present then you need rather ridiculous contraptions to start probing at the hard limits down there.

Even the LHC doesn't begin to approach the actual limits on how small a distance or short an interval of time can be. Last I checked we're still closer to the upper observational limits (we can't observe something bigger than the universe for longer than it has existed, at least not directly) though we might feel crushed into insignificance by the scale of structures like galaxy filaments and supercluster walls and shit... when you zoom down from there to here, and then keep going down to the LHC scales, you're still gonna be spinning that scroll wheel to keep zooming in for a lot longer than you would probably expect before it stops.

Whoever optimized this universe did a shitty job or they've literally got processor power falling out of their ass and in fact so many spare cycles that it is a major crisis so they need to wastefully spend them running this unnecessarily finely grained simulation?