"Perhaps it's lack of knowledge on my part, but I don't see what will stop atomic bombs from being as common as handguns in 30-100 years. Fissile material is ubiquitous; there's no barrier but economics and engineering, of exactly the sort near-term AI could unpredictably disrupt."
You guess right--it's your lack of knowledge.
Fissile material is not useful for making nuclear weapons (of any more than the dirty bomb variety). So far, we seem to have converged on uranium and plutonium, and while at least uranium is relatively common in the Earth the processing and dredging required to get a useful amount of it, and then the refining to get the useful isotopes from that, is nontrivial.
Engineering and fast computers are great and all, and will get you arbitrarily close to the physical limits--but we're there right now, and physics says you aren't getting a centrifuge with meaningful output in your garage.
More troubling is the idea that frankly we've had the technology to build sports cars in our homes for decades and decades now. It's called buying a lathe, an arc welder, a mill, a forge. Despite the availability--cheap!--of these things to the general populace, not only is it not widespread among those who can--and there are damned few of those even with this magical Internet thing telling you how to do all of it--it will get less likely as people focus on cat pictures and tweeting.
We aren't worthy of a singularity as a culture.
EDIT:
Thank you for attaching some interesting facts. Allow me to do the same:
Your hiking source claims uranium metal, but points out that it is completely locked up in slag and that only at large-scales does the approach seem tractable.
Even allowing for that, the amount produced is negligible.
That's just for metal--we aren't even talking about a usable isotope yet.
Take 7/1000 of that result from the blogger, and wave a wand to make it pure enough to use.
Now collect the (at least) several pounds needed of that to make a functioning device. Now do the machining on the rest of the device to make it function correctly (have fun with the berylium dust, if you go that route). Now do the timing electronics, and the charge shaping (if you go that route).
"Fissile material is not useful for making nuclear weapons (of any more than the dirty bomb variety). So far, we seem to have converged on uranium and plutonium, and while at least uranium is relatively common in the Earth the processing and dredging required to get a useful amount of it, and then the refining to get the useful isotopes from that, is nontrivial."
I did not express myself well; this is exactly my point -- the barrier to (U-235 based) nuclear weapons is isotopic enrichment -- very difficult engineering -- and not so much access to natural uranium -- raw materials. So that, should difficult engineering become unexpectedly easy (as with singularity-type scenarios), then would be no major barrier to weapons, as access to uranium cannot possibly be blocked.
"Thank you for attaching some interesting facts. Allow me to do the same:"
Apologies for editing and expanding my comment after you read it -- it's a bad habit. ("Release early and release often"?)
"Engineering and fast computers are great and all, and will get you arbitrarily close to the physical limits--but we're there right now, and physics says you aren't getting a centrifuge with meaningful output in your garage."
Could you elaborate on this? I know the underground Fordow complex is about 6,000 m^2 [Forden] -- only about 1-2 orders of magnitude off, and it's built for human workers to access (not robots). And there's at least a factor-of-4 miniaturization in current laser technology (refs [APS][NYT]). I can't describe a design for a garage-sized enrichment plant, but I don't know that it's strictly precluded by physics or engineering constraints.
"1.6 to 16 times more efficient than first-generation gas centrifuges"
Even taking the SILEX claims at face value, that's compared with first-gen gas centrifuges--presumably those used in the early 20th century.
That's still not going to produce output in a form factor usable in a garage. Moreover, the argument I'd posited earlier doesn't hinge on the refinement--the sheer issues of scale of processing for ingress that much raw material are what gets in the way. Then you also have to dispose of the waste tailings.
"A single centrifuge might produce about 30 grams of HEU per year, about the equivalent of five Separative Work Unit (SWU). As as a general rule of thumb, a cascade of 850 to 1,000 centrifuges, each 1.5 meters long, operating continuously at 400 m/sec, would be able to produce about 20-25 kilograms of HEU in a year, enough for one weapon."
Even going with the factor of 20 speedup (overestimation from your provided article with the SILEX quote), we would expect to need 50 centrifuges, on the order of 1.5m long each--that's quite a lot. There's also the supporting equipment, power conditioners and piping and so forth.
In fact, powering the entire apparatus is also a big concern. The article I linked suggests a power draw on the order of several hundred thousand kilowatt-hours (compare with around six thousand for a normal home per year) per year. So, again, I don't see the garage fab making sense.
Oh, and during all that time?
You bet your ass the government is datamining your browsing history, purchase orders, and hobbies. I've ignored it so far in the discussion, but if you want to play the magical singularity wand I'll play the fascist police state card.
> More troubling is the idea that frankly we've had the technology to build sports cars in our homes for decades and decades now. It's called buying a lathe, an arc welder, a mill, a forge. Despite the availability--cheap!
Now I'm curious. How much would it cost to set up a reasonable home garage with all this machinery?
Welder capable of welding tube frame for racecar, about $300 - $500
Cheap lathe (Chinese import 12x36 or old American) about $1500
Cheap mill big enough for automotive work (Chinese import or used American) about $1200
Cheap cutoff saw for most purposes: $100
Don't need a forge, just head over to www.onlinemetals.com to get any metal you're likely to need.
I agree with the poster: tools and knowledge on how to do this stuff is readily available (I downloaded a pdf of plans for a 22-caliber single shot pistol I will build someday), but very few people actually bother. Just like we have tons of cheap computers, but only a vanishingly small percentage of people bother to learn programming them...
Depends on your budget of course. Machine tools don't 'depreciate' past their accuracy. Which is to say that a mill that can hold one thousandth of an inch repeatably costs $X used and on that can do one ten-thousandth (tenth) repeatably is $10X.
The challenge of building a sports car is generally building your own engine (which people don't do often unless they are steam based). You need to get the engine block cast and that requires a steel foundry. Building a blast furnace in your garage is quite difficult if it needs to have the volume capacity to make even a fairly small engine block. Once you have the castings however the various other bits can fit in your garage easily and do cost between $8K and $150K depending on newness, accuracy, control methodology etc.
I'm also assuming that you would use fiberglass layup for the body panels since a sheet metal press that can make a 'hood' sized piece, or fender sized piece, is also quite large (and tall).
The challenge of building a sports car is generally building your own engine (which people don't do often unless they are steam based). You need to get the engine block cast and that requires a steel foundry.
Unless you just insist on starting with a home-made block, you can acquire "naked" engine blocks fairly easily. Or at least you could a few years ago, I've been away from that scene for a while, so my knowledge isn't completely up to date. And even if you can't get a naked block you can certainly get partially built engines (usually the block, crankshaft, pistons and connecting rods) or "crate engines" (usually everything except intake manifold and carburetor / fuel injector) straight from the manufacturers. For example, see:
'course, starting with a pre-forged block and partially built engine isn't quite like doing it from scratch, but then again, I'm assuming anybody building their own car is buying pre-rolled tubing and sheet stock, etc., not literally building everything up from iron ore, aluminum ore, etc.
Yes, any sane person would start there :-) I was just responding to 'build from scratch' which can be interpreted quite literally. A friend of mine builds race cars which are basically some 'regular' car, except all the structural bits get replaced. I joked with him that it would be simpler if he just took the engine out and built a frame around the engine, but he claims the previous frame are his version of a story stick[1].
A friend of mine builds race cars which are basically some 'regular' car, except all the structural bits get replaced. I joked with him that it would be simpler if he just took the engine out and built a frame around the engine.
Cool. My dad builds and races late model stock cars and has been involved in racing as long as I can remember... so yeah, I can relate to exactly what you mean there. The race cars have almost nothing left of the original car except the exterior sheet metal.
You guess right--it's your lack of knowledge.
Fissile material is not useful for making nuclear weapons (of any more than the dirty bomb variety). So far, we seem to have converged on uranium and plutonium, and while at least uranium is relatively common in the Earth the processing and dredging required to get a useful amount of it, and then the refining to get the useful isotopes from that, is nontrivial.
Engineering and fast computers are great and all, and will get you arbitrarily close to the physical limits--but we're there right now, and physics says you aren't getting a centrifuge with meaningful output in your garage.
More troubling is the idea that frankly we've had the technology to build sports cars in our homes for decades and decades now. It's called buying a lathe, an arc welder, a mill, a forge. Despite the availability--cheap!--of these things to the general populace, not only is it not widespread among those who can--and there are damned few of those even with this magical Internet thing telling you how to do all of it--it will get less likely as people focus on cat pictures and tweeting.
We aren't worthy of a singularity as a culture.
EDIT:
Thank you for attaching some interesting facts. Allow me to do the same:
The useful fissile uranium isotope (235) accounts for bout .72% of naturally occurring uranium (http://web.ead.anl.gov/uranium/guide/facts/).
Your hiking source claims uranium metal, but points out that it is completely locked up in slag and that only at large-scales does the approach seem tractable.
Even allowing for that, the amount produced is negligible.
That's just for metal--we aren't even talking about a usable isotope yet.
Take 7/1000 of that result from the blogger, and wave a wand to make it pure enough to use.
Now collect the (at least) several pounds needed of that to make a functioning device. Now do the machining on the rest of the device to make it function correctly (have fun with the berylium dust, if you go that route). Now do the timing electronics, and the charge shaping (if you go that route).
This.
Is.
Not.
Garage.
Technology.