How much time will it take the humanity to forget how to repair machinery after a nuclear apocalypse?

Question

I am building a world where a nuclear apocalypse happened, forcing humanity to hide in bunkers or avoid the radioactive fallout. Because of this, humanity forgot how to build things: they could survive on scrap technology they found like radiation suits. They used them to explore the cities and wastelands and find things there that helped rebuild cities and communities for them to live.

The main plot of my story is that the colonies chose a few of their inhabitants to go to the wasteland and find technology: light bulbs, wire, scrap metal. Anything that they could use to expand and rebuild their lives. But they go outside because the humans forgot how to build things that work. Is humanity losing the collective knowledge to create the technology that they must now scavenge even plausible?

Answer 1

"A nuclear explosion"? The largest H-bomb ever built would barely dent the world population. So, no your set-up fails the first test of its plausibility.

If some Aliens captured a group of people and isolated them, they could still teach their kids. Their kids would likely not learn anything that wasn't useful, unless it became part of their religion or myths; Norse epics come to mind. But you don't suggest these people are shut into caves with no tools.

So, your scenario fails its second plausibility test: there's no reason why people wouldn't be able to transfer any useful chemical, electronic, mechanical, etc. knowledge to their kids. We have these things called "books". Books are useful, even in caves. So, reading would be taught.

Your scenario fails this 3rd test of plausibility. You may already know this, but perhaps you don't: Our world is radioactive. We're exposed to radioactivity every day, a little bit more isn't going to do much to our over-all reproductive rate.

As a fourth test of plausibility, what are these people going to eat? We have no currently plausible alternative to growing crops using sunlight and large open areas for farming.

Answer 2

The first round of loss.

Your post-apocalypse world will lose whatever skills are not represented within your survivor pool. So if the bunkers or shelters or escape pods or mountain retreats don't include doctors, mechanics, carpentry, civil engineers, or whatever, then those skills are gone. Day one, hour one, minute one, gone. So you must not let your shelters be populated with random citizens only. You must select for the skills you need to survive. And in duplicate, so you have redundancy if someone dies. It also requires the safety to not focus all attention on self-defense. It also requires sufficient food that everyone alive isn't scrounging or farming.

The second round of loss.

The next round is from aging. So your survivors have skills. But they must have the resources to document those skills (wikipedia and how-to youtube videos are gone). And to teach those skills. They must have pupils ready and able to learn those skills. Otherwise, as your survivors die out over time, you lose those skills forever or nearly so. It also requires the safety to not focus all attention on self-defense. It also requires sufficient food that everyone alive isn't scrounging or farming.

The third round of loss.

The third round of loss is when equipment breaks down. So your mechanic can fix the engine. But he cannot fabricate replacement parts. She cannot refine petroleum-based lubricants without other machinery. They cannot produce new tires and gaskets and spark plugs and fuel filters without an entire global economy's worth of factories and mines and such. This is your third round of loss, when parts run out or begin to fail. There's no coming back from this loss; once your tank loses a critical part you cannot replace, that tank is just useless scrap metal. And if your premise is a world where everything has stopped -- except the shelters -- then there are no factories. There are no mines in operation, no oil pumps and oil refineries. And rebuilding those requires even more skills -- skills that are useless at day 1 and so are less important to pass on than other survival skills. So rebuilding that infrastructure will require decades.

Answer 3

This is a lot like Logan's Run. A nuclear apocalypse nearly destoys everyone, forcing them into protective, automated cities with limited resources, necessitating euthanasia at a very young age. Consequence? Nobody but the central computer has the skills to fix anything.

So, let's ignore how you're getting to the point of apocalypse and assume that some massive tragedy has occured that has...

• Wiped clean every hard drive on earth. This isn't that hard if it was a nuclear apocalypse.

• Burned every major city (say, 25K or 50K population and above) such that the only library records that might contain any (much less sufficient) technical information would be in rural homes and county libraries.

• Destroyed all major tech centers (like the [Google data center at The Dalles, OR; population 15K) are also burned.

• Killed all the technicians, or at least eliminated so much of the technology that there is no practical way to pass the knowledge on to the next generation. (Believe me, if you destroyed all the silicon fabrication facilities in the world and the previous points were true, it would be fundamentally impossible to preserve knowledge of how to build a fabrication facility.)

And now we make an assumption. What do you mean by "machinery?" Do you include small engine repair? Do you include manual printing presses? Have we lost basic metallurgical skills along with our "high tech" skills? Have we lost the ability to make a push lawn mower or a pair of manual hedge trimmers? You see my problem, of course. Sending us back to the 1500's would mean destroying all the data and everyone above the age of, say, 7. (Now we're talking about the Star Trek TOS episode Miri, which isn't dissimlar to Logan's Run.

Let's stick with just loosing the high-tech stuff. Basically, the ability to create a 1970s computer or newer, but maybe we still can figure out how to get an old coal electric plant running (unless they've been computerized...). How long would it take to forget all that?

As long as it takes for the last person to remember it to die, because there's so much involved with making a computer (design, fabrication, manufacturing, and software) plus all the modern infrastructure for it to be useful (everything from electrical power to the Internet) that there's no practical way for said person (if it's possible for just one person to have all that in their head. I feel safe saying it's not possible) to pass that information along.

TL;DR: 30-60 years.

Answer 4

I am positively sure all governments will safeguard a core population, i.e. scientists, doctors, engineers and researchers from all fields of sciences and provide them with all amenities and safehaven. I have not yet counted ordinary people yet, but many will be rescued. The end result is that tech advances will continue, albeit in more secured areas both above and under ground. Your assumption can only work if the number of survivors is too scarce and society is confined to isolated pockets. Assuming a "critical mass" or number of scientists is met, your scenario is unlikely to happen.

Second issue, is food. Assuming surface radiation is too high to grow crops in open fields, there are two possibilities:

1- heavy-duty greenhouses, screening-out radiation, but it seems hard to build and meet the deadline - Maybe I'm too pessimistic.

2- underground hydroponic system. Either one or the other must be built ahead of time. The underground has no light so artificial light is the only way through. To do it, the people may repurpose nuclear weapons to generate electricity, use solar panels or maintaining an existing nuclear plant in working condition.

Answer 5

You need to revise your premise and expand the scope of the disaster.

A single atomic bomb will not do what you think it will. The US dropped two such bombs in Hiroshima and Nagasaki. People live in those cities today. Wildlife is coming back today, only a few decades after the 1986 Chernobyl accident, which released 20 times the radiation of the Hiroshima bomb.

Unlike in the game Doom, radiation suits do little to stop gamma radiation irradiation (they may block some, but you need more than 1.27cm of lead to stop it. You can't walk in that.) What they do is prevent the contamination of clothing and skin. If fitted with a breathing device, it can prevent irradiated particles from causing damage to your lungs and other internal organs.

However, to address your central Creating and repairing technology is part of the material culture. As such, it would be passed down from parent to child. The problem is that a man might know how to fix an air conditioner, but not know how to mine iron, make steel, produce freon, or the thousands of other related steps needed to produce the technology. A Doctor could transmit her knowledge of medicine to her children, but does not know how to create antibiotics from scratch, nor does she have the electrical knowledge to create the defibrillator. So some knowledge would be preserved, but other knowledge would go away. People would still create things, but the level of technology would be about the 1800's to 1900's level.

Answer 6

It's up to you

This really depends on a) how many people survive and b) who survives.

But it's unlikely that the survivors would gradually begin to forget as you describe. It's more likely that knowledge would be lost instantaneously, but gradually begin to recover.

What would probably happen is that, of the survivors, there would be a number of engineers, mechanics, technicians, electricians, plumbers, etc. These people would probably not cover all of the technology requiring repair, but would cover some of it and be able to figure out more (e.g. similar technology to what they know). Then, that out of necessity, the others would learn, probably with the help of the surviving tech people mentioned above. Their would be some technology which could possibly never be repaired. (e.g. try to fix a computer without a factory to make replacement parts) - but again this ability would be instantly lost after the nuclear explosion, not forgotten over time.

Perhaps your situation could happen if, for example, very few repairmen survived, and for some reason or another, didn't share their knowledge, taking it to the grave with them. I don't know, maybe in the new order their skills have become being highly valuable and they don't want to share.

Then the answer to your question is: however long they live.