The Librarian's Notebook
A page of Leonardo da Vinci's notebook: lines of his right-to-left mirror writing in brown ink, with two small pen sketches of a bird in flight in the right margin and a diagram of a wing's rigging below them
Folio 17 verso of Leonardo da Vinci's Codex on the Flight of Birds (c. 1505, Biblioteca Reale, Turin): mirror-written notes, two birds, a rigged wing — one page of the most famous notebook ever kept, in which anatomy, hydraulics, optics, a shopping list and a flying machine share the same paper. Public domain, via Wikimedia Commons.

A commonplace book — science and technology, the world, arts and culture, and whatever else didn't fit

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TECHNOLOGY · SEPTEMBER 12, 2026 Antarctica Gained 695 Billion Tons of Ice, and the Reason Was Seven Thousand Kilometres Away Between July 2021 and April 2023 the Antarctic ice sheet got heavier by about 695 billion tons — the largest gain in the twenty-four-year satellite-gravity record. A paper in Nature traces it to a warm patch of tropical ocean that bent the atmosphere over East Antarctica and turned it into a snow funnel. The headline is a gift to anyone who wants to misread it. The paper is not: two decades of losses at 140 billion tons a year are still there, and the gain is a weather event, not a trend. TECHNOLOGY · SEPTEMBER 12, 2026 Eight Years to Mercury, and One Chance to Stop On 3 September the BepiColombo spacecraft, two hundred million kilometres from Earth, let go of the engine that carried it for eight years and 9.9 billion kilometres. On 21 November it has to stop at Mercury, the hardest planet in the solar system to arrive at, using a sequence it will run on its own because the radio round-trip is too long to help. A 2024 power fault already cost it eleven months. This is what it is for, why the arrival is so hard, and what the last flyby found on the way in. CULTURE · SEPTEMBER 12, 2026 Escape, and the Four Times I Paid for It The second entry in my Journey series is the record that got me — Escape, July 1981, the first with Jonathan Cain, the one with "Don't Stop Believin'" on it. It came to me off the radio, and then I bought it on LP, and then on cassette, and then on CD, and then took it for free on Napster like everybody did, and now I stream it like everybody does. I have paid Journey many times over for the same music. I do love them, so it's okay. TECHNOLOGY · SEPTEMBER 12, 2026 Galileo's Experiment, Done With One Atom in Two Places A team including Roger Penrose has dropped a rubidium atom that was, in the quantum sense, in two places at once — one half falling freely, the other held still — and read off how gravity changed it. Einstein's equivalence principle survived. What makes it worth an entry is not the result but the ladder it starts: the same instrument, with heavier and heavier objects, could eventually test Penrose's own idea that gravity is what stops big things from being in two places at once. He helped build the tool that could prove him wrong. CULTURE · SEPTEMBER 12, 2026 Raised on Radio, the One I Have to Defend My favorite Journey album is not Escape and not Frontiers. It's Raised on Radio, from 1986 — the one Steve Perry produced himself, the one made after two founding members were let go, the one the band never quite recovered from. This is the entry where I say why: it was mostly Perry, it mixed his voice with the new synthesizer sound of the mid-eighties in a way that felt beyond normal music to a fourteen-year-old, and "The Eyes of a Woman" still moves me and "Girl Can't Help It" is still what I drive to. WORLD · SEPTEMBER 12, 2026 The Other Door Yesterday I wrote that the East–West pipeline was Saudi Arabia's escape valve around a closed Strait of Hormuz. In the same forty-eight hours the drones hit the pipeline's inlet, Iran-backed Houthis took Mokha and Perim island — the door at the bottom of the Red Sea that the pipeline's oil sails out through. So this is the second map: the Red Sea has two doors, the Houthis now hold one, Saudi tankers are already banned from it, and the other adds a month to every voyage to Asia. NOTES · SEPTEMBER 12, 2026 The Second Plane Twenty-five years ago I was woken up in California to watch the second plane go into the tower. This week 2,977 drones rose over New York Harbor, one for each person, and built the towers again for a few minutes at full size. It got to me more than I expected, and I've been trying to work out why — and why it landed in the same week that drones set fire to a Saudi pipeline and a widow stood at Ground Zero to say the country had spent twenty-five years protecting the Saudis instead of her. TECHNOLOGY · SEPTEMBER 12, 2026 The Week the AI Labs Asked to Be Regulated In one week in September 2026: OpenAI shipped a model its president called the start of the AGI era, then asked Congress for mandatory safety rules it had spent two years opposing; it put its most prominent internal critic on the board, and he said the industry was not on track; Anthropic published a report saying its own model had been used to write missile-guidance software in Yemen and to run the largest data-theft campaign it had ever measured. I use one of these tools every day. This is an attempt to say what changed, and what the three explanations are. TECHNOLOGY · SEPTEMBER 12, 2026 Two Nanometres of Nothing: What Apple's New Chip Actually Changed The A20 Pro in the iPhone 18 Pro is the first phone chip made on a "2-nanometre" process. Nothing on it is two nanometres wide; the number stopped measuring anything about a decade ago. What did change is real and fourteen years overdue: the transistor's gate now wraps all the way around the channel instead of three sides of a fin. This is what that means, why the fin had to go, and why the label survives anyway. CULTURE · SEPTEMBER 12, 2026 Why Journey My favorite band, of all time, is Journey. This is the first entry of a series about them — not a history of the band, which exists already and was written by people who were in the room, but one record at a time, each paired with where I was when it reached me. It starts with why, with the singer who is the reason, and with a confession about a song I somehow missed for five years. TECHNOLOGY · SEPTEMBER 11, 2026 My Collaborator Has No Memory Except the Notes I Keep for It For three months I have worked every day with an AI coding assistant that wakes up each session knowing nothing about the last one. What it knows, it reads from a file. That file grew to 685 kilobytes, went stale in ways that reached the real-money side of the project, and turned into the best lesson in institutional memory I have had. This is what it is like to run a one-person shop with an amnesiac partner, and why the answer turned out to be less writing, not more. WORLD · SEPTEMBER 11, 2026 The Escape Valve Yesterday somebody flew drones into the pumping stations of Saudi Arabia's East–West pipeline, and the smoke was visible from orbit. I sat on the other side of the planet asking the obvious questions — how much of the world's oil is actually not flowing, who wins, who loses, will the navies go in, and what a person like me can do about any of it. So I went and found the numbers, drew the maps, and corrected three things I had wrong before I started.

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