If all man-made things were wiped out, how long would it take to re-create modern civilization?

Disappointed in the post. Are we trying to rebuild civilization or find a new big prime number?

I say it would take at least a generation to get back to where we are, once you throw in the logistics of smelting iron with no pre-existing furnaces, city planning, etc. What would be interesting is how we could rebuild from scratch without the bother of skirting around the burned out districts of older cities. Maybe we would skip right over iron and build skyscrapers out of carbon fiber...

PS- when the skyscrapers suddenly disappear, the rich folks in the penthouses will have a long way to fall... at least they will have a lot of poor people to land on. It will get messy, regardless.

theJeff wrote:

Are we trying to rebuild civilization or find a new big prime number?

Is either one possible without the other?

If you rebuild civilization, some mathematician, nerd, and/or group of people with way too much time on their hands will try to find a big prime number for bragging rights.

If you just want to find that prime number, you'll almost certainly have to rebuild a large part of civilization. How are you going to find that prime number without modern electronics?

I think it can be done in about 50 years under ideal conditions where everyone cooperates. But it'll probably take 200-300 years when you factor in all the delays due to wars, pandemics, and the like.

It will probably take as long as it did the first time around.

The people with the most useful knowledge will be the guys in airplanes, skyscrapers, cruise ships, cars, and subways. Most if not all of them will be wiped out in the apocalypse. The survivors will be those that know the least. The homeless bum on the street, the uncontacted jungle tribe, the subsistence farmers of the third world. No written knowledge will survive.

You know what, scratch that. Civilization will never be re-created if the OP's scenario were to happen.

theJeff wrote:

when the skyscrapers suddenly disappear, the rich folks in the penthouses will have a long way to fall... at least they will have a lot of poor people to land on. It will get messy, regardless.

Well, at least we've solved income inequality.

Prisoners will be running loose and will form gangs that control access to vital resources.

The inhabitants who are most familiar with modern technology live in the northern latitudes and will almost certainly freeze to death.

A few generations later, people will forget all of this and treat the whole thing as an ancient myth. The world will become and remain a collection of hunter-gatherers and small farming villages.

pessimist wrote:

It will probably take as long as it did the first time around.

The people with the most useful knowledge will be the guys in airplanes, skyscrapers, cruise ships, cars, and subways. Most if not all of them will be wiped out in the apocalypse. The survivors will be those that know the least. The homeless bum on the street, the uncontacted jungle tribe, the subsistence farmers of the third world. No written knowledge will survive.

You know what, scratch that. Civilization will never be re-created if the OP's scenario were to happen.

The most useful knowledge would be hand to hand combat, improvising weapons and shelter, and the skills needed to live off the land. I doubt you’d find those in a skyscraper or an airplane.

I’d guess the hunter gathering types that still exist would fare the best, but they won’t rebuild your prime number finding Hal.

Younger, healthy types that have some sort of skill in the manual arts might do ok. If they were to provide for the more erudite engineer types who survived the fall from the vanished sky scrapers, then maybe we could get back to today’s technology in 200 years or so.

bronze age wrote:

theJeff wrote:

Are we trying to rebuild civilization or find a new big prime number?

Is either one possible without the other?

If you rebuild civilization, some mathematician, nerd, and/or group of people with way too much time on their hands will try to find a big prime number for bragging rights.

If you just want to find that prime number, you'll almost certainly have to rebuild a large part of civilization. How are you going to find that prime number without modern electronics?

I think it can be done in about 50 years under ideal conditions where everyone cooperates. But it'll probably take 200-300 years when you factor in all the delays due to wars, pandemics, and the like.

You can certainly rebuild civilization without finding the next biggest prime number. We are doing it now, in fact.

Most people have little to no skill in finding food or in defending themselves from people armed with improvised weapons. However, everyone would recognize the need to feed, shelter, and protect computer programmers and mathematicians, who would be essential to re-creating the computer age and getting our civilization back.

You can probably guess what would happen. Everyone who's not physically strong and skilled would claim to be a programmer or a mathematician. With few ways to verify either claim, the real programmers and mathematicians would get killed in the chaos just like everyone else.

Even after we got a stable source of food and water, how are we going to create anything that resembles a computer? The math and the programming is the easy part. What rare earth elements do we need, we can we find them, and where do they go on the computer? How are you going to construct circuits that are thousands of times thinner than a human hair?

Not only that, but how are we going to save and transmit any useful knowledge? Do we use rocks to chisel basic mathematical formulas onto other rocks? How many people even know how to manufacture pencil and paper from scratch?

I can't see this ever happening again. We got lucky the first time around with geniuses who won't be coming back.

depends theres a lot of vairubowls, like u sayin even the russians and chinese n koreans n canadians they the same level military and everythin as america because military man made? well whats to keep them from buildin a few boats and sailin right on over and attackin are asses before we even new what was comin?

Even if everyone cooperates, this is going to be tough if not impossible. With no medication, diminished physical ability, and an unreliable source of food, almost all of the 70+ year olds will be dead within weeks. They are the ones who are most likely to know how to build and operate moderately advanced technology such as blast furnaces and internal combustion engines.

Now we get to the food and shelter problem. What berries are edible? What are we going to eat while we wait for next year's crop to grow? Forget hunting big game; with no weapons or traps, can you even catch a squirrel or a rabbit to eat? Trees can be used for firewood and shelter, but how are you going to either create an axe or chop a tree down without one?

After solving those problems, you got a whole bunch of other issues to deal with. Eventually, you'll hit the really hard ones. How are you going to build satellites and launch them into space? How does the internet even work?

Here's how I would rank some possible outcomes in order of likelihood:

1.) Humanity gets to a stage that resembles the Roman empire. It falls due to disease, corruption, apathy, and/or invasion by other tribes. A few hundred years pass, a new empire rises, and the cycle repeats.

2.) Humanity becomes and remains a loose collection of hunter-gathering tribes for tens of thousands of years. Eventually, we become extinct due an asteroid impact or a supervolcano eruption.

3.) Humanity goes though another industrial revolution and is destroyed once nukes are invented.

4.) Humanity succeeds and builds something that resembles a modern computer. We get to where we are today.

There's a reason why we haven't heard from ET yet. It ain't easy.

It would take a very long time. Everyone with knowledge of the modern world will have died off in 2 generations. No transportation, no way to contact others outside of your immediate area. You're going to be with the people physically closest your neighbors. Unless you live with your family. And traveling to other friends and family would be difficult. You would have no way to know if they are even in that location, you would have to find your way there, you are only able to go as fast as the slowest member of your group.

It'll never happen. Newton, Edison, Euler, Turing, and all of the other past geniuses are no longer there to guide us, and most of the world's knowledge will be wiped out in the apocalypse.

The other poster said it right, we got incredibly lucky the first time around.

Maybe the new crop of “strong women” can rebuild the infrastructure.

How do you expect to even write down a million-digit prime number without rebuilding civilization to nearly its present state first? By which point, all the original victims of your evil wizard will have died naturally, and their descendants would only be wrecking themselves and everything they created if they revived the legendary world of their ancestors.

I have no idea about an answer, but you might want to check this out as a fun example of 'modern civilization' (in the form of a toaster) and what it takes to build one 'from scratch':

https://www.ted.com/talks/thomas_thwaites_how_i_built_a_toaster_from_scratch

Bad Wigins wrote:

How do you expect to even write down a million-digit prime number without rebuilding civilization to nearly its present state first? By which point, all the original victims of your evil wizard will have died naturally, and their descendants would only be wrecking themselves and everything they created if they revived the legendary world of their ancestors.

Large numbers aren't written down digit by digit lol. 2^77,232,917 − 1 is the current largest

Let’s also not forget that everyone from the Great Lakes/New York latitudes northward would suddenly be buried under a mile of ice. (OP said 20,000 years)

The Sahara would be lovely, though.

Seriously. There are so many layers of technology needed to build a computer capable of calculating such a large prime number that just keeping programmers around would be like a Shogun keeping a guy around that might eventually be able to fly a Zero.

If some sort of library were to be left available, then there would certainly be a chance.

I'm no computer scientist or mathematician, but I think this could be done within 10-20 years. All you need is the prime number, everything else in our society can be discarded. Skyscrapers? No need. Modern roads? No need. Spacecraft and cable TV? Don't bother. We can leapfrog over technologies like papyrus and morse code.

Put everyone to work extracting the raw materials for a computer, building the computers and power plants, and maintaining only the basic life essentials. The computers don't even have to be as good as modern ones; just redirect everyone to mass produce them like we did for WW2 tanks. Unlike today, every computer in the world will trying to find that friggin' number.

The main wildcard would be how well the survivors cooperate. Some marginalized people don't want the 2018 world back and will try to sabotage the effort.

alternate view wrote:

I'm no computer scientist or mathematician, but I think this could be done within 10-20 years. All you need is the prime number, everything else in our society can be discarded. Skyscrapers? No need. Modern roads? No need. Spacecraft and cable TV? Don't bother. We can leapfrog over technologies like papyrus and morse code.

Put everyone to work extracting the raw materials for a computer, building the computers and power plants, and maintaining only the basic life essentials. The computers don't even have to be as good as modern ones; just redirect everyone to mass produce them like we did for WW2 tanks. Unlike today, every computer in the world will trying to find that friggin' number.

The main wildcard would be how well the survivors cooperate. Some marginalized people don't want the 2018 world back and will try to sabotage the effort.

Yeah, but everyone would be dead. Earth cannot support 7.5 billion hunter gatherers and that’s what we’d all have to be. 20,000 years ago, none of tje domesticated food crops would be around. Try feeding people on the ancient land races of maize or wheat.

Modern farmers would be useless as well. Perhaps subsistence farmers from the developing world might have the skills to feed themselves, but your average beer gut tractor driver would starve just like the rest of us.

Honestly the hardest part would be finding and assembling all the right people in one place before they died living in the wild. The computing power necessary to find million+ digit primes is not very extensive and the algorithms that find them would still be stored away in certain peoples minds. If you had the right people working together I bet it could be down within a few years. 20 at the most.