Things I Learned in 2025

With 2025 behind us, the numbers look bleak. My five-year average for “Things I Learned” is 61 factoids, but last year fewer than 20 items made it onto the list. Not to worry, though: 2026 is on track to return to the greatness of yore.

1. The white stuff in your cheese isn’t mold (and it isn’t “salt crystals”) 🧀 Different cheeses form different crystals. Aged cheddar and Gouda often develop calcium lactate crystals on the surface as calcium salts migrate and recrystallize. Washed-rind cheeses may show salt crystals from surface treatments. Long-aged hard cheeses such as Parmigiano-Reggiano and Grana Padano (and also aged Gouda) can develop tyrosine crystals within the paste. Tyrosine is an amino acid released during proteolysis as casein breaks down during aging, and its low solubility makes it prone to crystallize.

   Could still be mold, though 😄

2. Baby teeth show when a baby was breastfed 🦷🤱 This can serve as a record of prenatal and early-childhood exposure to toxic metals. By using barium to mark the moment of birth and align growth layers, researchers can reconstruct when (and roughly how much) lead entered the body.

3. Ancient fish are the origin of toothache when eating something cold 🦷🐟 Dentin, the nerve-linked inner layer of our teeth, first evolved as a sensory tissue in the mineralized exoskeleton of ancient armored jawless fish. It likely served for sensing temperature, pressure, and other stimuli. (Via University of Chicago)

4. “Scuba” as in scuba diving is an acronym for “Self-Contained Underwater Breathing Apparatus” 🤿

   It was coined by Christian J. Lambertsen in a patent submitted in 1952. (Via Reconcilable Differences)

5. All of the Agent Orange sprayed in Vietnam contained just 80 liters of dioxin, the toxic component ☢️ However, more recent estimates put the total much higher, at ~366 kg of dioxin. That’s roughly ~200 to 220 liters (about the size of a large bathtub).

6. The name Aspirin was constructed by Bayer in 1899 to combine the drug’s chemical and botanical origins 💊

   • A-: from acetyl, referring to the acetyl group added to salicylic acid to form acetylsalicylic acid (the active ingredient)

   • -spir-: from Spiraea (now Filipendula ulmaria), the genus name of meadowsweet, a plant rich in salicylates and a key source material in salicylic acid chemistry

   • -in: a common pharmaceutical suffix at the time, used to form pronounceable drug names

   Thus, Aspirin = acetyl + Spiraea + -in.

7. Insulin is named after the islets of Langerhans 🧂

   The pancreatic islets or islets of Langerhans are the regions of the pancreas that contain its endocrine cells (hormone-producing cells), discovered in 1869 by German pathological anatomist Paul Langerhans.

   The name “insulin” was coined by Edward Albert Sharpey-Schafer in 1916 for a hypothetical molecule produced by pancreatic islets of Langerhans (Latin insula for islet or island) that controls glucose metabolism. Unbeknown to Sharpey-Schafer, Jean de Meyer had introduced the very similar word “insuline” in 1909 for the same molecule.

   (Via Patrick Kelly)

8. Spider webs were used for the crosshair in telescopes 🕷🔭 Spider silk was historically used as reticles (crosshairs) in optical instruments like telescopes and theodolites, used for triangulation in geodesy, surveying, and mapping. Spider silk worked well because it has a tiny, uniform diameter, high tensile strength with minimal sag, and low sensitivity to humidity and temperature.

9. The British were able to defeat Napoleon because they had access to a bond market and could obtain the funds they needed on short notice [Citation needed] Britain’s access to deep and credible public credit markets was an important enabling factor in the Napoleonic Wars, but it wasn’t the only factor, and it’s not a complete explanation for Napoleon’s defeat.

   But I heard about it on a podcast and can’t find a credible source. So now I’m passing this half-truth on to you, dear reader!

10. The Arctic is named after Ursa Major 🐻🌟 The brown bear is Ursus arctos, while the polar bear is Ursus maritimus. Arktos is Greek for bear. Arctic comes from Greek arktikós (“of the bear” / “northern”), referring to the northern sky and the constellation Ursa Major (the Great Bear). In that sense, “Arctic” roughly means “land of the bear.”

11. When Neil Armstrong flew to space on Gemini 8, plate tectonics was not widely accepted, but when he landed on the Moon three years later it was the mainstream consensus 🌎🚀 This blew my mind 🤯

    Bonus: Plate tectonics is not the same as continental drift (TIL) (Via the ever so great XKCD)

12. Why the Week Has Seven Gods

13. Can You Power Your Computer By Typing? No. Betteridge’s law strikes again… But seriously: typing a character is about 1.5 mJ. That’s enough energy to lift a squirrel by 300 µm (about four sheets of paper) or heat a tiny drop of water (0.05 ml) by about 0.01 °C. Did I mention that XKCD is great, again? Same goes for the YouTube channel.

    This got me thinking, though. Using this approximation, it would take ~3,000 keystrokes (as I’m typing this, we’re at 7,950) to lift a squirrel by 1 meter. And it would heat a drop of water by about 30°C. Once again: water’s heat capacity is ridiculous.

    P.S.: The actual numbers for the water are \Delta T &= \frac{Q}{m \cdot c}. With Q the heat energy added (1.5 mJ), m is the mass of the water (0.05 g), c is the specific heat capacity of water (≈4.184 J/g⋅K) ΔT=\frac{0.0015 J​}{0.05 g⋅4.184 J/g*K} \approx 0.00717 °C So actually typing 3,000 characters would heat the drop of water by less than 22°C. Crazy!

14. Argentina is named after the element of Silver (argentum)

15. The elements of Yttrium (Y), Ytterbium (Yb), Terbium (Tb), and Erbium (Er) are all named after the Swedish village of Ytterby Guess they’re still looking for Bium (Bm) 🤪.

    Other elements chemically identified using minerals from the Ytterby quarry:

    • Holmium (Ho): from Holmia, the Latin name for Stockholm
    • Scandium (Sc): from Scandia, Latin for Scandinavia
    • Thulium (Tm): from Thule, a classical name for a northern land (often associated with Scandinavia)
    • Gadolinium (Gd), named after Finnish chemist Johan Gadolin
    • Tantalum (Ta)

    Bonus: Tantalum is named after Tantalus, a figure in Greek mythology. He was made to stand in a pool of water beneath a fruit tree with low branches, with the fruit always just out of reach and the water receding when he tried to drink. His name and punishment are also the source of the English word tantalize, meaning to torment with the sight of something desired but out of reach; tease by arousing expectations that are repeatedly disappointed.

    (Via Rob Watts)

16. Ever heard of a wenis 🍆? (Via Kottke)

17. New evidence pushes back the date of human fire mastery by 350,000 years 🔥 A couple years here, a couple years there, and suddenly we’re talking about real time…

18. Lizards love four cheese pizza 🦎🧀🍕

    Rainbow lizards […] were observed while feeding […] pizza and showing a clear preference for […]‘four cheeses.’

    Would have loved to see that proposal for funding 😄

    (Via Methodisch Inkorrekt)