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I keep a stack of books on my desk I plan to read next and the stack has not changed in six weeks. |
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Humans do keep making new brain cells into old age |
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In 2013 Jonas Frisén's lab at Karolinska Institutet used carbon-14 dating of neurons to argue that cells in the adult human hippocampus continue to turn over throughout life. The field accepted it. Then in 2018 Shawn Sorrells and colleagues published in Nature using antibody staining on postmortem tissue and found almost no new neurons after childhood. Textbooks hedged. The field split and stayed split for years. In July 2025 Frisén's group was back in Science, this time with Marta Paterlini as first author. They used single-nucleus RNA sequencing on brain tissue from donors aged 0 to 78 and found actively dividing neural progenitor cells in the dentate gyrus of adults. Not many. Some donors had plenty, others had almost none, and variation on this scale was difficult to see with the staining methods used in the 2018 study. What irritates me is how this gets described outside the journals. The claim is that the biological machinery for making new neurons is present in some adult brains. That is a different claim from "exercise grows your hippocampus" or "learning a language rewires your brain." Nobody has shown a lifestyle variable moves this process in a living human. The debate is only about whether the raw capacity exists at all. |
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Telegraph operators are why your keyboard is in this order |
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Christopher Latham Sholes patented his first typewriter in Milwaukee in 1868. The familiar story is that letters were scattered to stop the mechanical typebars from jamming on common pairs. That story is incomplete. Common pairs like "er" are right next to each other, and Sholes himself kept filing alternative layouts for years, not confident he had the right one. Koichi and Motoko Yasuoka at Kyoto University went looking at the surviving paper trail and argued the arrangement was finalised for telegraph operators transcribing Morse. The signal for Z in American Morse was often confused with the digram S-E, so S, E and Z ended up close together, so an operator could type them in whichever order the message resolved. Every laptop in the café I'm sitting in is a frozen artefact of a nineteenth-century workaround for a code almost nobody still writes. |
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The world's highest permanent town is a Peruvian gold camp |
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La Rinconada sits in the Peruvian Andes at 5,100 metres, about 16,700 feet, and somewhere between thirty and fifty thousand people live there depending on how the gold price is moving. There is no plumbing. Mercury from informal gold processing contaminates the drinking water and the glacier above the town. Most miners work under an arrangement called cachorreo. They dig for free for most of the month, and on a day or two the operator lets them keep whatever ore they can carry out. If the rock they chose that day is barren, they worked for nothing. Women are barred from the mines on a local superstition that their presence angers the mountain. Many instead work the tailings outside as pallaqueras, sifting discarded rock for anything the men missed. The town grows and shrinks with the price of gold, and in a bad year a lot of people walk out and never come back. |
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Americans bought more heat pumps than gas furnaces last year |
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The Air-Conditioning, Heating and Refrigeration Institute, a trade body that counts shipments from US manufacturers, reported that air-source heat pumps outsold gas furnaces in 2024 by thirty-two percent. The year before, the lead was twenty-one. The year before that it was smaller again. A heat pump is just an air conditioner that can run in reverse. It takes heat out of outdoor air, even when outdoor air feels cold, and moves it inside. The electrical versions have been around since the 1850s in rudimentary form and in houses since the late 1940s, which is why I keep forgetting this counts as new technology. A quiet caveat the AHRI numbers do not solve: a single gas furnace sometimes gets replaced by two or three heat pump units, so unit-count leads can run ahead of the actual share of homes that have switched. The direction of travel is still unambiguous. |
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One percent of users write most of what everyone else reads |
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In October 2006 the usability researcher Jakob Nielsen posted a short piece on his company's website arguing that participation on the internet is heavily skewed, which was obvious to anyone who had read a comments section. His specific numbers are what stuck. Ninety percent lurk, nine percent contribute occasionally, one percent produce almost all the content. He called it the 90-9-1 rule. Nineteen years later the ratios still roughly hold. Nielsen pointed out that Wikipedia is far more lopsided, with something like 99.8 percent reading, 0.2 percent occasional editors, and about a thousand hyperactive volunteers doing two-thirds of the actual edits. Blog ratios ran around 95-5-0.1. I find this calming. When someone talks about "what people are saying on Twitter" or "what everyone on TikTok thinks," they are describing the output of a very small, very loud group. Everyone else is quietly reading, and probably agreeing with less of it than the volume suggests. |
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The 90-9-1 rule is the one I'd retell at dinner tonight. |
