52 Things I Learned in 2025

Here are some of the most interesting things I learned this year.

1. Until very recently, networks didn’t save live television footage because storage costs were too high. The only reason we have access to footage that aired between 1979 and 2012 is because a woman from Philadelphia recorded it and saved it on over 40,000 VHS tapes. (The Nineties)

2. Coal-burning plants release 100 times as much radiation as nuclear plants per megawatt of power produced. (The Infinite Resource)

3. Amazon averages one software deployment every second. (Brave New Work)

4. A 12th century law requires that a bale of hay be hung to warn mariners on the Thames when there are restricted bridge heights, and failure to hang it results in fines up to £5,000. Right now, scaffolding on the Hungerford Bridge into Charing Cross Station has triggered the bale-of-hay warning. At night, the hay is illuminated. (IanVisits)

   

5. Birders in the United States spend $107 billion per year, including $93 billion on binoculars, feeders, cameras, and other equipment; and $14 billion on travel. That’s more than the GDP of New Hampshire. (“Birding in the United States”)

6. In 2024, the word “delve” appeared in journal abstracts 28X more frequently than in 2022 because ChatGPT likes the word delve. (“Delving into LLM-assisted writing in biomedical publications through excess vocabulary”) This is partly because OpenAI uses human feedback to refine its models, and many of these humans are from Nigeria, where “delve” appears more frequently in English spoken in formal settings. (“TechScape: How cheap, outsourced labour in Africa is shaping AI English”)

7. There are almost 1,000 hotels in China that include “Vienna” in the hotel name, compared to only 15 in the actual city of Vienna. Worldwide, hotels with “Vienna” in the name are an average of 8,416 km from the city of Vienna. (Towards Data Science)

   

8. The average West Virginian eats more than one hot dog per day. (Food Republic)

9. According to a 1983 United States Supreme Court decision, tomatoes are a vegetable. (Nix v. Hedden)

10. You are 7% more likely to die on your birthday than on the other 364 days of the year, partly because of the increased likelihood of accidental death caused by celebratory behavior. (The Pudding)

11. People who feel forgiven by God are 2.5 percentage points less likely to apologize to others. (“Implications of Divine Forgiveness for Conciliatory Behavior”)

12. Comedy clubs in the UK are banning audience members with Botox, which limits their ability to display a full range of facial expressions like smiling, depriving comedians of real-time audience feedback. People are asked to perform “expression tests” at the door, and those who fail are denied entry. (The Independent)

13. Noise-canceling headphones are causing hearing problems in young people, not because they’re listening with the volume too high, but because blocking ambient noise prevents the brain from learning to filter and process everyday background sound in the real world. (BBC)

14. Average sentence length in novels has shrunk from 20-45 words in the 1820s to 10-25 words in the 1920s. (Works in Progress)

    

15. Women are more likely to believe ghosts are real; men are more likely to believe aliens are real. (Gallup)

16. Before the October 19, 2025 heist in which the French crown jewels were stolen, the Louvre’s video security password was LOUVRE. (Vice)

17. Before 2010, menstrual cycles (n=176) showed a statistically significant peak alignment with the full and new moons (though the correlation was weak: r ≈ 0.15 to 0.20, p < 0.001), but this synchronization has since almost disappeared (p > 0.05) because of the widespread use of LEDs and smartphones. (“Synchronization of women’s menstruation with the Moon has decreased but remains detectable when gravitational pull is strong”)

18. About 88–95% of plastic found in the ocean comes from just 10 rivers. (“Export of Plastic Debris by Rivers into the Sea”)

19. The longest a drinking straw can be is 33.8 feet. Beyond that length, the weight of the water is greater than the atmospheric pressure required to push it into your mouth. On Jupiter, maximum straw length is 13.4 feet. On the sun, it’s just 2.3 inches. (@fermatslibrary)

    

20. Dating your manager typically comes with a 6% raise! But there are downsides: retention of your co-workers drops 6%, and if you break up, your earnings go down 18%. Morale plummets, too. (“The Impacts of Romantic Relationships with the Boss”)

21. ChatGPT’s efficiency per prompt has improved 33X the past year, falling to 0.0003 kWh, roughly the energy required to stream Netflix for 8–10 seconds or conduct a Google search in 2008. Total AI data center water usage is also now equivalent to 3% of the water used by all U.S. golf courses. (Andy Masley)

22. In the 1980s, the price of orange juice futures was better at predicting the weather in central Florida than the official forecasts by the National Weather Service. (“Orange Juice and Weather”)

23. In Norway, if you want to change your last name to one held by fewer than 200 people in the country you need to get permission from all of them first, as stipulated by the Names Act of 2002. There are fewer restrictions on first and middle names, which is why there are, right now, six Norwegians with the middle name “Batman.” (“Banned Names in Norway”)

24. New York City has seen a spike in the number of apartment buildings with exactly 99 units after the state legislature passed a bill requiring wage increases for developers of buildings with 100 units or more. Twenty-eight permits for 99-unit buildings were filed last year, compared to 14 permits the previous sixteen years combined. (“NYC developers build 99-unit buildings to avoid wage requirements”)

25. Before agriculture, a square mile of land could feed about a quarter of a person, but today, the same square mile feeds almost 1,300 people. (The Infinite Resource)

26. GDPR rollout reduced U.S. venture capital investment in EU startups: investors participated in 21% fewer deals and invested 13% less overall. This is roughly $1.6 billion less per year since GDPR was implemented in 2018. (“Privacy Regulation and Transatlantic Venture Investment”)

    

27. In team sports, women are 13.69 times more likely to be attacked by a fellow teammate than men. (“Sex differences in exclusion and aggression on single-sex sports teams”)

28. In Mexico, extending the school day by 3.5 hours led to a 12.6% increase in divorce rates. The extra time made it more likely for women to participate in the labor market, thus increasing their economic independence. (“Parents’ effective time endowment and divorce”)

29. Beijing planted one-third of a million acres of trees between 2012 and 2020 to reduce air pollution, and though the project reduced particulate matter by 4.2% and saved billions in health costs, it increased pollen exposure by 7.4% and led to an extra 1,200–1,500 allergy-related ER visits each year. (“Urban Forests: Environmental Health Values and Risks”)

30. 327 people were responsible for one-third of all shoplifting arrests in New York City in 2024. (New York Times)

31. Toast actually does usually land butter-side down. Toast starts rotating as soon as it falls off a table. The torque applied by gravity as the toast tips off the table initiates rotation, but the rotational dynamics, constrained by average toast width of 3.9 inches and the fall time from an average table height of 30 inches, restrict the motion to just over half a rotation, which isn’t enough to bring the butter-side up before impact. For toast to land butter-side up, average table height would need to be about 9.8 feet. (“Tumbling Toast, Murphy’s Law and the Fundamental Constants”)

    

    
    

32. In 1985, the average man in his 30s could squeeze your hand with about thirty more pounds of force than the average woman, but today, men and women have roughly the same grip strength. (Of Boys and Men)

33. When a plasma donation center opens, the demand for payday loans drops 13-18%, foot traffic at nearby businesses goes up 4.3%, and the crime rate within the same census tract drops 2.1%, largely driven by a decline in property crimes and drug-related offenses. (“Blood Money: Selling Plasma to Avoid High-Interest Loans”)

34. The average American consumes around 100GB of information per day, up from 75 GB/day in 2015, 63 GB/day in 2012, 34 GB/day in 2008, and 7.5 GB/day in the 1970s. (Optimaze)

35. If you have a son, the chances of your next child being a boy are not 50%, they are actually 57%. (“Trends in Population Sex Ratios May be Explained by Changes in the Frequencies of Polymorphic Alleles of a Sex Ratio Gene”)

36. The Super Bowl is responsible for an additional 17 to 18 million pounds of avocado consumption. (Reuters)

37. 63.8% of cats (n=301) sleep on the left. (“Lateralized sleeping positions in domestic cats”)

    

38. All things being equal, the liquid inside a glass bottle contains more microplastics than the liquid inside a plastic bottle—up to 50X more! This is because plastic-coated metal caps found on glass bottles shed more particles than plastic caps found on plastic bottles. (“Glass Bottles Produce More Microplastics Than Plastic Bottles”)

39. In 2011, because of declining birthrates and demographic shifts, adult diaper sales surpassed baby diaper sales in Japan. (Economic Times)

40. Paternity leave reduces fertility, according to a 2007 study of Spanish parents. Compared to men who were ineligible for paternity leave, men who receive time off experience a drop in the number of desired children, from 2.33 to 2.26, roughly aligning with women’s preference for 2.25 children. (“Does paternity leave reduce fertility?”)

41. There is a massive, continent-sized blob (the technical term is “large low shear velocity province”) about 1800 miles below the Earth’s crust under the Pacific Ocean. It is called “Jason.” (Wikipedia)

    

42. Residents of Black neighborhoods wait 29% longer on average to vote than residents of White neighborhoods, and they are 74% more likely to spend more than 30 minutes at their polling place compared to residents from all White neighborhoods. Wait times are not affected by voter ID laws, “arrival bunching,” party affiliation, or whether black voters live in red or blue states or counties. (“Racial Disparities in Voting Wait Times: Evidence from Smartphone Data”)

43. Iceland has such low a homicide rate and so many crime writers that part of the job of its only forensic pathologist, Pétur Guðmannsson, includes hosting writing seminars. (CBC)

44. A round-trip direct flight to Washington, D.C. from a member of Congress’s hometown is associated with a 1.5 percentage point increase in the probability that that member of Congress runs for reelection. (“Transaction Costs and Congressional Careers”)

45. Before 2000, it was common for 10% of Americans to have the same favorite athlete. The 10% threshold was last crossed in 2003, and since 2014, no more than 5% of Americans have had the same favorite athlete. This trend reflects a broader shift away from monocultural sports consumption, where everyone watches the same sports on a few channels, and a shift toward the fragmentation of sports media, where audiences are split across digital platforms and niche interests, preventing any single athlete from dominating the national consciousness. (Reddit)

    

46. The Burj Khalifa, the tallest building in the world, exerts less pressure on the ground than a person standing in stiletto heels. The building weight 500,000 tons, but exerts a ground pressure of only 90 psi, compared to the 850 psi exerted by a single stiletto heel. The Burj Khalifa would need to be about 18 miles tall to exert the same amount of pressure on the ground as a person standing in heels. (@teddyg0tsauce)

47. After a woman born with three fingers had to have her hand amputated, the phantom limb she developed had all five fingers. This is because the brain’s 5-finger blueprint overrides the experience of living with a physical limb with three fingers. (“This Woman Was Born With Three Fingers, But Her Brain Knew All Along What Having Five Would Feel Like”)

48. The probability that all adults in Home Alone oversleep and almost miss their flight is about 0.13%, or roughly one in 750 weekend nights. (“How Likely Was the McCallister Oversleep? A Gaussian Model of Home Alone”)

49. The screens of all laptops in Apple stores are set at an angle of exactly 76 degrees, which is just awkward enough to invite people to tilt them back a bit more, thereby taking the first step toward interacting with the product. (Business Insider)

50. Most people are capable of five levels of mentalizing (I [1st level] believe that you [2nd level] want him [3rd level] to think that she [4th level] understands him [5th level]), which is why the funniest jokes hit this sweet spot—fewer than five, and they’re not complex; more than five, and the audience can’t follow. For example: you [1st level] hear the line, “They [2nd level] don’t know that we [3rd level] know they [4th level] know we [5th level] know!” (“The Complexity of Jokes Is Limited by Cognitive Constraints on Mentalizing”) This is also why people have, on average, five intimate friends, and why conversation groups that exceed five people always split into two conversations. (Friends)

    

    
    

51. No NFL game has ever ended with a score of 36–23. Across the approximately 17,000 games that have been played in NFL history, this score should have happened 2.68 times by now. The probability of this score never occurring is 4.9%: across roughly 20 parallel universes, we happen to live in the one without this score. (“Scorigami: Simulating the Distribution and Assessing the Rarity of National Football League Scores”)

52. Between 2012 and 2022, the number of children in England needing surgery to remove a foreign body from the nose fell 31%. This is caused by the rise of cashless payment apps, which have reduced the need for adults to carry around loose change. (The Guardian)

The best books I read in 2025 were, in the order I read them: The Nineties, Status and Culture, Gray Matters, Spellbound, Breakneck, Abundance, When Everyone Knows that Everyone Knows…, and Warriors and Worriers.

This list was inspired by Tom Whitwell’s list, recommended.

Previous 52 things I learned: 2024, 2023, 2022, 2021, 2020, 2019, 2018