179 votes
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What would an immortal-run American bank have to do to secretly maintain bank accounts for immortal customers?

Maintain a Bank Account for Above-Board Immortals American law already grants personhood to immortal, soulless entities bent on twisting the minds of innocents to their will and consuming everything ...
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170 votes
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How might modern humans leave a message for 50,000 years?

My first thought is redundancy. You shouldn't send just one copy of the message, you should send thousands and through different methods. Some thoughts on possible methods: Rock carving in a ...
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  • 25k
159 votes

How might modern humans leave a message for 50,000 years?

There's a very specific existing case study of nearly this exact question. In the 1970s, the US Department of Energy began investigating what is now known as the Waste Isolation Pilot Plant as a means ...
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  • 1,651
133 votes
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My characters have been killing the same demons over and over again. How come the demons never adapt to them?

Why would they? They're just here to punch the clock. Invading planets nine to five, then check out and relax. And you know what? If you get killed, you get a vacation. Of course, it must not be ...
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  • 3,975
116 votes
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What skills would an early-1500s era ship captain need to learn to become a modern-day sailor (and eventually a captain again)?

My qualifications I was a qualified Officer of the Deck in the US Navy. I have around 2000 hours watchstanding time and about 50 port and anchorage transits. Navigation skills A (competent) 1500s ...
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111 votes

Great Old Ones Limited, or Why does Cthulhu need a Company?

It IS a front because if you openly state as the firm's mission and vision to summon a destroyer of worlds your business isn't going very far. Aside from that, there are some things that dark cults ...
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108 votes
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Reasons why healthy people would intentionally want to get infected?

Natural Vaccination. Read about how Cowpox was used to vaccinate against Smallpox, this is our IRL first instance of vaccination against a disease. The word “vaccination,” coined by Jenner in 1796,...
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97 votes

Dragons and aviation bureaucracy

Dragons would run the FAA One day, you're flapping along, torching pigeons, and those runty little ground creatures that taste good with ketchup start making an awful racket. "Must be that Henry ...
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  • 45.6k
91 votes
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What US states are most likely to rebel?

It's Texas. The big problem with an entire state rebelling is the rest of the US starving them of resources. Like, for instance, electricity. Most people aren't aware that a majority of the United ...
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  • 48k
90 votes

Are there any mathematics that could only be learned by very few people?

Main Answer I have a PhD in Mathematics and came across this question. To be honest, I dislike almost every single answer, except maybe L.Dutch's answer concerning Wile's proof of Fermat's last ...
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88 votes
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Great Old Ones Limited, or Why does Cthulhu need a Company?

Have YOU ever tried setting up classic rituals? Everything's going well with everyone in their matching robes and masks, and just as the Grand Priest is finishing the ritual to summon a Great Old One ...
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85 votes

How might modern humans leave a message for 50,000 years?

I think we can all agree that whoever finds this message in 50,000 years isn't going to speak English. Or Mandarin. Or Hindi, French, Spanish, Swahili, or, in fact, any language spoken today. So we'll ...
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83 votes

Where on Earth is it easiest to survive in the wilderness?

As a native I'm definitely biased here, but Ireland is actually a pretty good bet. Especially towards the West, Ireland has actually seen a decline in rural population. You can genuinely walk for ...
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  • 1,557
80 votes

Reasons why healthy people would intentionally want to get infected?

Because some self-proclaimed health guru claims that it's good for you to have that disease. The miracle-virus causes your body to absorb free cosmic energies. Your constantly raising body ...
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79 votes
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Would gorillas with human-level intelligence make effective soldiers?

They would make great infantry, and would pose a serious threat on the battlefield. Stronger Gorillas are stronger than a human being, and capable of carrying far more equipment/armor. Each of ...
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73 votes

Fallout from aliens destabilizing economy by counterfeiting all global currencies?

what policies would the world's various administrations put in place? Switch to digital currencies and eliminate paper money. Explain to the nice aliens that we were just settling on paper money. ...
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  • 25k
72 votes
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How would modern naval warfare have to have developed differently for battleships to still be relevant in the 21st century?

TLDR: All you need is better Anti-Aircraft Guns There's a lot of good information here, but I think @Karl actually has the best and simplest answer to the question. Imagine a scenario where instead ...
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71 votes
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Why would people let a super tree grow?

The tree was never supposed to be a tree, it was supposed to be a natural boost to the air quality and be a feature of the building. The architect had a great idea for a natural air circulation and ...
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  • 114k
66 votes
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How fast can I flood the Netherlands entirely and permanently?

Can't realistically be done. As you pointed out, there is not enough water on the Earth. You could get away with a Grote Mandrenke, but no more (and you want "permanent"). Adding that much water ...
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66 votes

How can medieval knights protect themselves against modern guns?

This is basic asymmetric warfare. It can work. Ask the Viet Cong how they held off the most powerful superpower in the world... What you don't do is take on the modern army on their terms, or even ...
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65 votes

Could a natural disaster completely isolate a large city in the modern world without destroying it?

Totally possible. 2 million Australian's came very close in "20 bloody 20" About 80% of your requirements were met in 2020. 12 days of total isolation is a little shy of your requirements. A ...
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62 votes
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How can my town be public knowledge while still keeping outsiders out?

The answer to this is very simple: make the entire town into a gated community. Encircle the whole place with a fence and have guards on the gates who are or can pass for human. The guards would ask ...
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  • 45.6k
61 votes

What would an Earth with no timezones be like?

For their day to day lives, people in different parts of the world would associate different times with different activities. While to someone in Greenwich 11:30 am might mean "lunch time", to people ...
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  • 13.6k
58 votes

How much smarter would bred humans become?

Intelligence is not a singular trait There are many facets to intelligence. Let's start with some animal examples: Dogs. Everybody loves dogs and dogs love everybody. They have incredible social ...
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58 votes
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What do fairies wear and how can they evade detection by our cameras?

They paint their wings like giant butterflies Rainforests house many colorful butteflies, some with wingspans of 4-5 inches. With painted wings and carefully chosen clothes and a bit of bodypaint, ...
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54 votes
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A person from medieval times comes into our time. What would he notice first?

The smell. We don't notice it because it is everywhere but even low-level pollution would be noticed immediately -- the ability to smell low-level pollution would pass quickly though. The noise. ...
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  • 20.9k
54 votes

My characters have been killing the same demons over and over again. How come the demons never adapt to them?

They do not know what the tactics were Combat is a horribly confusing environment to be in. No one has the full picture of exactly what happened afterwards - recollections of individuals are ...
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  • 19.1k
52 votes

How to prevent criminal gangs from making/buying guns?

Real life solution - make guns scarce in your society In a country like US, where there are plenty of guns among the citizens, it's a no-brainer for criminals to use guns too. If they choose melee ...
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  • 41.2k
52 votes

Famous conjecture or unsolved problem that could be plausibly proven/solved by freshman mathematician?

Since you're interested in something currently unsolved, you don't really care about how protagonist will solve it, only that he does so, let's go for something extremely simple, simple enough that ...
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51 votes
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How to prevent criminal gangs from making/buying guns?

My home country (China) has very strict gun control laws. Basically, normal citizen will not be allowed to buy, sell guns, or make it themselves. If guns are involved in a crime case (say, robbery), ...
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