this post was submitted on 26 Jun 2025
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There have been a number of Scientific discoveries that seemed to be purely scientific curiosities that later turned out to be incredibly useful. Hertz famously commented about the discovery of radio waves: “I do not think that the wireless waves I have discovered will have any practical application.”

Are there examples like this in math as well? What is the most interesting "pure math" discovery that proved to be useful in solving a real-world problem?

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[–] [email protected] 23 points 1 day ago (1 children)

The invention of the number 0, the discovery of irrational numbers, or l the realization that base 60 math makes sense for anything round, including timekeeping.

[–] [email protected] 13 points 21 hours ago (2 children)

60 was chosen by the Ancient Sumerians specifically because of its divisibility by 2, 3, 4, and 5. Today, 60 is considered a superior highly composite number but that bit of theory wouldn’t have been as important to the Sumerians and Babylonians as the simple ability to divide 60 by many commonly used factors (2, 3, 4, 5, 6, 10, 12, 15) without any remainders or fractions to worry about.

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[–] [email protected] 19 points 1 day ago (1 children)

Having watched all the veritasium math videos I feel like all the major breakthroughs in math were due to mathemicians playing around with numbers or brain teasers out of curiosity without a concrete use case in mind.

[–] [email protected] 6 points 21 hours ago (1 children)

It’s crazy how engaging and well done Veritasium videos are and they’re just free to watch on YouTube.

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[–] [email protected] 22 points 1 day ago (1 children)

If I recall correctly, one mathematician in the 1800s solved a very difficult line integral, and the first application of it was in early computer speech synthesis.

[–] [email protected] 16 points 1 day ago

the man you're thinking of is, I believe, George Boole, the inventor of Boolean algebra.

[–] [email protected] 41 points 1 day ago (1 children)

A brain teaser about visiting all islands connected by bridges without crossing the same bridge twice is now the basis of all internet routing. (Graph theory)

[–] [email protected] 6 points 1 day ago

freaking freaky little Russian outpost that one is. Bridges galore

[–] [email protected] 10 points 1 day ago

Not math but the discovery of Thermus aquaticus was seemingly useless but later had profound applications in medicine. There's a good Veritasium video on it

[–] [email protected] 72 points 1 day ago (3 children)

The math fun fact I remember best from college is that Charles Boole invented Boolean algebra for his doctoral thesis and his goal was to create a branch of mathematics that was useless. For those not familiar with boolean algebra it works by using logic gates with 1s and 0s to determine a final 1 or 0 state and is subsequently the basis for all modern digital computing

[–] [email protected] 23 points 1 day ago (1 children)

Shoutout to Satyendra Nath Bose who helped pioneer relativity as a theoretical physicist because he didn't want to study something useful that would benefit the British.

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[–] [email protected] 25 points 1 day ago

George Boole introduced Boolean algebra, not Charles. Charles, according to this site on the Boole family, he had a career in management of a mining company.

[–] [email protected] 9 points 1 day ago (1 children)

Was he trying to dunk on his professors?

[–] [email protected] 5 points 1 day ago (1 children)
[–] [email protected] 15 points 1 day ago (1 children)

Non-linear equations have entered the chat.

Chaos and non-linear dynamics were treated as a toy or curiosity for a pretty long time, probably in no small part due to the complexity involved. It's almost certainly no accident that the first serious explorations of it after Poincare happen after the advent of computers.

So, one place where non-linear dynamics ended up having applications was in medicine. As I recall it from James Gleick's book Chaos, inspired by recent discussion of Chaotic behavior in non-linear systems, medical doctors came up with the idea of electrical defibrillation- a way to reset the heart to a ground state and silence chaotic activity in lethal dysrhythmias that prevented the heart from functioning correctly.

Fractals also inspired some file compression algorithms, as I recall, and they also provide a useful means of estimating the perimeters of irregular shapes.

Also, there's always work being done on turbulence, especially in the field of nuclear fusion as plasma turbulence seems to have a non-trivial impact on how efficiently a reactor can fuse plasma.

[–] [email protected] 9 points 1 day ago (1 children)

A good friend of mine from high school got his physics PhD at University of Texas and went on to work in the high energy plasma physics lab there with the Texas Petawatt laser, and a lot of the experiments it was used for involved plasma turbulence and determining what path energetic particles would take in a hypothetical fusion reactor.

[–] [email protected] 6 points 1 day ago (2 children)

Be honest, how many unofficial experiments were there?

You ever just start lasering shit for kicks?

[–] [email protected] 7 points 1 day ago

Probably not as many as we'd like to think. I recently got to run a few days of tests at Lawrence Livermore National Labs with an absurdly massive laser. At one point we needed to bring in a small speaker for an audio test. It took the lab techs and managers about two hours and a couple phone calls to some higher ups to make sure it was ok and wouldn't damage anything. There's so much red tape and procedure in the way that I don't think there's an opportunity to just fuck around. The laser has irreplaceable parts that people aren't willing to jeopardize. Newer or smaller lasers are going to be more relaxed. This one is old enough to be my father, and it's LLNL's second biggest single laser iirc. And they are the lab using lasers for fusion, so they have big lasers.

[–] [email protected] 2 points 1 day ago* (last edited 1 day ago)
[–] [email protected] 14 points 1 day ago (1 children)

I've read that all modern cryptography is based on an area (number theory?) that was once only considered "useful" for party tricks.

[–] [email protected] 9 points 1 day ago* (last edited 1 day ago) (1 children)

prime number factorization is the basis of assymetric cryptography. basically, if I start with two large prime numbers (DES was 56bit prime numbers iirc), and multiply them, then the only known solution to find the original prime numbers is guess-and-check. modern keys use 4096-bit keys, and there are more prime numbers in that space than there are particles in the universe. using known computation methods, there is no way to find these keys before the heat death of the universe.

[–] [email protected] 12 points 1 day ago (2 children)

DES is symmetric key cryptography. It doesn't rely on the difficulty of factorizing large semi-primes. It did use a 56-bit key, though.

Public key cryptography (DSA, RSA, Elliptic Curve) does rely on these things and yes it's a 4096-bit key these days (up from 1024 in the older days).

[–] [email protected] 2 points 1 day ago
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[–] [email protected] 42 points 1 day ago (3 children)
[–] [email protected] 3 points 1 day ago

The exact example I also thought of from the question! Well done

[–] [email protected] 6 points 1 day ago (1 children)
[–] [email protected] 5 points 1 day ago (2 children)

Quake, not Doom. Doom didn't use true 3D rendering and had almost no dynamic lighting.

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[–] [email protected] 23 points 1 day ago* (last edited 1 day ago) (7 children)

Complex numbers. Also known as imaginary numbers. The imaginary number i is the solution to √-1. And it is really used in quantum mechanics and I think general relativity as well.

[–] [email protected] 13 points 1 day ago

It's used extensively in electronic circuit design (where it's called "j", as "i' already meant electronic current).

Also signal processing has i or j all over it.

[–] [email protected] 11 points 1 day ago (1 children)

I’m the akshually guy here, but complex numbers are the combination of a real number and an imaginary number. Agree with you, just being pedantic.

[–] [email protected] 4 points 1 day ago (1 children)

Sure, but 1 is a real number. 😜

[–] [email protected] 6 points 1 day ago (1 children)

Yes, and 1 is also a complex number.

[–] [email protected] 4 points 1 day ago (1 children)

Of course, but 1 is the loneliest number.

[–] [email protected] 4 points 1 day ago

2 is as bad as 1: it's the loneliest number since the number 1.

[–] [email protected] 5 points 1 day ago

Electromagnetics as well.

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