I'm reminded of the famous story of (I think) the central beam in a building at Oxford. The story goes something like:

The central beam was beginning to fail and the Oxford administration knew they needed to replace it. When they went around for quotes, no one could replace the beam because it was 100 ft in length and sourced from an old growth tree. Such logs were simply unavailable to buy. To solve the issue, the staff begin to look at major renovations to the building's architecture.

Until the Oxford groundskeeper heard about the problem. "We have a replacement beam," he said.

The groundskeeper took the curious admins to the edge of the grounds. There stood two old growth trees, over 150 feet tall.

"But these must be over 200 years old! When were they planted?" the admins asked.

"The day they replaced the previous beam."

Here's another good example of a series of slow experiments: the cosmic distance ladder.

https://www.youtube.com/watch?v=YdOXS_9_P4U https://en.wikipedia.org/wiki/Cosmic_distance_ladder

You can compute the distance to the moon if you know the radius of the earth by looking at how long lunar eclipses take, data gathered over years of observations.

Eratosthenes computed the radius of the earth by clever trigonometry in ancient times, and Aristarchus computed that a 3.5-hour lunar eclipse indicates that the moon is ~61 earth radii away.

Once you have the distance to the moon, you can compute the size of the moon by measuring how long it takes the moon to rise. It takes about two minutes, and so the radius of the moon is about 0.0002 of the distance to the moon.

By cosmic coincidence, the sun and the moon appear to be approximately the same size in the sky, so the ratio of radius/distance is approximately the same for the sun and the moon. If you measure phases of the moon, you'll find that half moon is not exactly half the time between the full moon and new moon. Half moon occurs not when the moon and the sun make a right angle with the earth, but when the earth and the sun make a right angle with the moon.

You can use trigonometry to measure the difference between the half-time point between new/full moon, and the actual half moon, giving you an angle θ. The distance to the sun is equal to the distance to the moon divided by sin(θ).

To get θ exactly right, you need a very precise clock, which the Greeks didn't have. It turns out to be about half an hour. Aristarchus guessed 6 hours, which was off by an order of magnitude, but showed an important point: that the sun was much larger than the earth, which was the first indication that the earth revolved around the sun. (Aristarchus' peers mostly didn't believe him, not simply out of prejudice, but because the constellations don't seem to distort over the course of a year; they were, as we now know, greatly underestimating the distance to nearby stars.)

Next, you can compute the shape of the orbits of the planets, by observing which constellations the planets fall inside on which dates over the course of centuries. Kepler used this data first to show that the planetary orbits were elliptical, and to show the relative size of each orbit, but with only approximate measures of the distance to the sun (like the θ measurement above) there's not enough precision to compute exact distances between planets.

So, scientists observed the duration of the transit of Venus across the sun from near the north pole and the south pole, relied on their knowledge of the diameter of the earth, and used parallax to compute the distance to Venus, and thereby got an extremely precise measurement of the earth's distance to the sun, the "astronomical unit." It took decades to find the right dates to perform this measurement.

The cosmic distance ladder goes on, measuring the speed of light (without radar) based on our distance to the sun and the orbit of Jupiter's moon Io, using radar to measure astronomical distances based on the speed of light, measuring brightness and color of nearby stars to get their distance, measuring the expected brightness of variable stars in nearby galaxies to get their distance, which provided the data to discover redshift (Hubble's law), measuring the distance to far away galaxies (and thereby showing that the universe is expanding).

In my free time, I have taken to trying to prove the Collatz conjecture.

People much smarter and more educated than me have failed at this quest, so I will nearly certainly fail at it, but that's not really the point in my mind. Even if I'm not the one to actually prove it, I can at least try and contribute to the body of work towards proving it. Mathematics is, more than nearly anything else, the result of generations building upon previous generations work. It's never "done", always growing and refining and figuring out new things to look at.

I have a few ideas on how to prove Collatz that I have not seen done anywhere [1], and usually (at least for me) that means it's a bad idea, but it's worth a try.

One of the greatest things about humans is our willingness to have multi-generational projects. I think maybe the coolest thing humans have ever done was eliminate smallpox, and that took hundreds of years.

[1] Which I'm going to keep to myself for now because they're not very fleshed out.

    The 2nd Ave Subway in Manhattan, with
    preparatory construction beginning in
    1942. First phase opened in 2017.

Although the outcome should be celebrated, the slowness and the added costs that brings certainly should not be.

    While every project is unique, it is not
    immediately clear why digging a subway
    on the Upper East Side is twenty times
    more expensive than in Seoul or ten
    times more expensive than in Paris.

https://marroninstitute.nyu.edu/blog/costly-lessons-from-the...

here's a even more damning look: https://www.vitalcitynyc.org/articles/why-it-costs-4-billion...

edit: I've been on a tirade about this subject this week. https://www.brethorsting.com/blog/2025/07/state-capacity-and...

A friend of mine once wrote a dictionary[1]. It has all the (normal) one syllable words in English, defined using only other one syllable words. He decided to work on it by focusing on one letter per year, so A was in 1991, B was 1992, and the book was finished in 2017, 26 years later.

It's not even a very long book - only a few hundred pages - but I'm sure if I tried to do the same thing all at once, I'd probably have lost interest around B or C, so I suppose it was a worthwhile strategy.

[1] It's not online anywhere as far as I know, sorry.

The SAS is a joke, putting its name on the same list as actually impressive feats like the proof of Fermat's Last Theorem insults everything else on the list. It's the most expensive subway line worldwide per mile, ever, despite the existence of technology that made tunnelling easier. Inflation adjusted, it costs more per mile than hand-digging one of the PATH tubes with 1900s technology [1]. Its cost and duration are almost entirely due to politics and not technical and logistical challenges, including the MTA political fiefdom fighting the Park Board political fiefdom, make-work-program labour spending, staff paid to have their thumbs up their asses in the tunnels [2], deep-bore tunneling instead of cut-and-cover to avoid political fighting, and MTA departments wanting their miniature fiefdom dug into the ground at each station [3]. The SAS is a project that should bring great shame to everyone in charge and everyone who stood around in the tunnels getting paid to do nothing.

[1] https://en.wikipedia.org/wiki/Uptown_Hudson_Tubes (tunnel happens to be about a mile and it cost 21 million 1905 dollars)

[2] https://www.nytimes.com/2017/12/28/nyregion/new-york-subway-...

[3] https://pedestrianobservations.com/2023/12/09/the-mta-sticks...

I dunno. I think we should separate out the stuff that fundamentally has to take a long time, like the pitch experiment, from stuff like Notre Dame, which just took a long time because they lacked the resources to do it all at once. Like OK, it takes a long time to build a big church because you need to find all the right rocks or whatever. But the pitch, that’s the universe taking a long time to tell us something.

(I’m being flip for comedy/emphasis sake, of course Notre Dame is pretty impressive too).

This reminded me of an old comic or meme about people’s expectations about science that went like:

Protester: What do we want??

Crowd: High quality, double blinded, N of 100000, 20 year longitudinal, preregistered studies!!

Protester: When do we want it??

Crowd: Now!!!

Related by content (OP says "This page is a riff on Patrick Collison's list of /fast projects"):

Fast - https://news.ycombinator.com/item?id=36605912 - July 2023 (298 comments)

Fast (2019) - https://news.ycombinator.com/item?id=30872279 - March 2022 (97 comments)

Fast - https://news.ycombinator.com/item?id=21848860 - Dec 2019 (291 comments)

Fast · Patrick Collison - https://news.ycombinator.com/item?id=21355237 - Oct 2019 (5 comments)

--

Also related, if only by title, this from yesterday:

Fast - https://news.ycombinator.com/item?id=44736967 - July 2025 (418 comments)

Kind of amusing to have this at the top of the front page considering “Fast” was there yesterday

Kudos to the OP for writing this.

That PC post always irked me. Not because it showed positive examples of going fast but because it felt slightly demeaning to teams/projects that move slowly on purpose, with intent.

I think of The Art of Computer Programming...

https://en.wikipedia.org/wiki/The_Art_of_Computer_Programmin...

The Art of Computer Programming has been a work in progress since 1962.

That’s longer than some of the list items.

Most democracies have elections every 4 or 5 years. That is good, in that we can get rid of underperforming politicians and parties. But it is bad, in that there isn't a lot of incentive for politicians and parties to plan over a longer timescale than 4 or 5 years.

China has the opposite problem. It can plan and finance long term projects. But there is little prospect of peacefully changing the leadership.

>A fun question: of these projects, which required a long time, and which could have been greatly accelerated?

Pretty much everything on the list is a research study of a long-term process that is inherently impossible to accelerate.

From the list, only the Second Avenue Subway and the Sagrada Familia unambiguously qualify as projects that could be greatly accelerated. The SAS was not under active construction for the vast majority of the time between 1942 and 2017 — actual construction only happened for a couple years in the early 70s, then another couple years in the late 80s, and finally from 2011-2017. The fits and starts were due to a combination of bureaucratic red tape, economic woes, and gross incompetence. The Sagrada Familia has also seen only intermittent construction over the last century, primarily because of lack of funding.

I personally find these examples underwhelming. Most of them are processes that require time, like the pitch drop experiment.

I suspect that the things in our lives that truly have value and take a long time aren’t easy to identify as projects. No one person starts it with a clear idea of where it will end. Investment in future capabilities. Knowledge gathering without clear application or business model. Strengthening institutions and traditions of human rights to ensure that no one group can arrest history.

Two more to add to the list:

– The Voyager probes were launched in 1977 and reached interstellar space in the 2010s. https://en.wikipedia.org/wiki/Voyager_program

– The oldest bonsai have been in training for centuries. https://en.wikipedia.org/wiki/Bonsai

This goes hand in hand with the Lindy effect[0]. Some of the examples given in the article are a testament to it.

[0]: https://en.wikipedia.org/wiki/Lindy_effect

I'm reminded of the quote: “Never give up on a dream just because of the time it will take to accomplish it. The time will pass anyway.”

The article conflates a few different "slow" projects, rather than the premise which is efforts that required decades to come to fruition.

He mentions projects started long ago but are still ongoing, like the Sagrada Familia. Then there's innovations from long ago which are still being used, like Linux. Also, he includes ideas which took decades to finally be implemented, like LIGO.

In my opinion, none of these examples are particularly good at demonstrating, "What problems can human beings only solve over a very long period of time?", except for Fermat's Last Theorem.

All technology builds on that which came before, step by step. You can trace Unicode directly back to Morse Code, via various steps like ASCII, Telex, Baudot Code, etc. But the original goal of Morse wasn't to display emojis.

I'd say General Relativity might be a good example, starting with Newton's efforts to quantify the forces of the real world, ending with Einstein's explanation of spacetime. But again, it's not as clear of a problem as Fermat's Last Theorem which was a single problem that required centuries to solve.

AI may be a good example as well, starting with the advent of the digital computer. The very first scientists who worked with them like von Neumann immediately looked forward to the day of an electronic brain. It's taken nearly a century so far and is still underway.

Neural network was introduced in 1950s. However, the neural architecture, the compute and data required for them to be efficient has been only in last decade.

From perceptron to transformers (few hidden layers to 480B parameters), from multicore CPUs to distributed GPUs and WWW/social media has all contributed to the growth of Artificial Intelligence.

This has took almost 50+ years and so many iterations along the way.

I like this list (and Collison's)!

One thing I would say -- the Sagrada Familia definitely didn't have to take the incredible time it has. Maybe not a good example of something that could only be done over the long term. Gaudi didn't prioritize it, and a civil war ruined it.

It is, however, an example of something beautiful that did take a long period of time.

You can watch the Pitch drop experiment [1] live here http://thetenthwatch.com/feed/

[1] https://en.wikipedia.org/wiki/Pitch_drop_experiment

Language itself is an interesting problem. We have texts that are ancient and some are unreadable and others are readable. I personally can't understand old variants of English while (American) English is the only language I speak.

There is so much assumed in our use of language that it can be largely unintelligible without detailed historical context. The first time I heard the term "in the car park" I chuckled at the thought of an amusement park for cars... "parking lot" only came a few thoughts later. We drive on parkways. We play in the park. We park in the lot. Lots are reading this sentence twice. Give this paragraph to a school-kid in just 100 years and it will seem like gibberish. Word.

As an academic, I fairly resonate with this message. Also notice that most examples he noticed are from academia/science endeavors. I see academia as probably the only place where slow projects are expected and even encouraged; think of PhD students working on basic science problems, often supported for 5-7 years at end (of course close to minimum wage).

This is not to hide that all slow undertakings are good or anything. Often because of inefficient executions or bureaucratic hurdles, academic suffers. But, I am trying to highlight the observation that how a slow and steady progress is the typical modus operandi for an academic lab/group. A famous saying comes to mind: Rome isn't built in a day.

Looking forward to Tao’s book on the subject. This is worthy of its own post, thanks for sharing.

Beat me to it. Indeed, from that video I learned that astronomy work requires large and/or longitudinal datasets.

I loved the tidbit that Galileo had a spat with Tycho Brahe because Brahe wouldn't share his data, so Galileo stole it (?)

solid! thank you!

Thank you.

A related thing occurs in academia for very niche topics on which only very few people are working. Perhaps nobody for most of the time. A paper might "reply" to another paper from years or decades ago, and receive itself a reply only years later, but from a different author.

The cool thing is that you can easily become the current world leading expert on such a niche topic, because there aren't that many papers. So it's easy to know every single one of them, and the few experts are spread out in time rather than space.

It's like a web forum thread on a very obscure question, where only every few years someone contributes a new comment, likely never to be read by most of the previous authors, but read by all that come later.

And it’s not only never done, it’s always on the verge of dying off. Like Bill Thurston said, mathematical understanding basically lives in communities of mathematicians, every one of them a cell in the superorganism that is the field. You’re part of the distributed filesystem providing persistence as well as the possibility of new understanding.

https://mathoverflow.net/questions/43690/whats-a-mathematici...

Interesting new contender for simplest to state unsolved problem: The Antihydra

Does this program halt?

  a = 8
  b = 0
  while b != -1:
      if a % 2 == 0:
          b += 2
      else:
          b -= 1
      a += a//2

(// being integer division, equivalently a binary shift one to the right: >> 1)

https://www.sligocki.com/2024/07/06/bb-6-2-is-hard.html

https://bbchallenge.org/antihydra

Reminds me of Stewart Brand and the Clock of the Long Now (and other longer time horizon projects they are working on).

Reminds me of a statement he made during a Tim Ferris interview that I think is quite profound for our mental health. ".... being proud is the most reliable source of happiness that I know."

Super enjoyed this read today. And a much shorter punchline. https://www.volts.wtf/p/us-transit-costs-and-how-to-tame https://bsky.app/profile/volts.wtf/post/3lvbpy6p2zk2c

It's just so sad having a nation where disbelief & being against things is so the spirit.

The “it is not immediately clear” part should be taken to heart a lot more than it is. Right now I’d bet you could elect Ezra Klein president and he would be as unable to improve things as most, and he probably has a somewhat clearer picture of the factors than your average internet commentator.

Railing against optimizing for caution in a vague sense really isn’t articulating specific dynamics however well it leans into the shallow strawmanification of “regulation” that doesn’t merely dominate lay discourse but has essentially ascended into conceptual godhood without having paid real dues in sacrifice or insight.

There is no respectable theory of why that has even begun to grasp the problem.