Library
Moments
One moment a day, a real scene from history explained and placed in context. Each belongs to a daily connection alongside one word and one idea.
Feathers beside a dinosaur's tail
A fossil discovered in the Bavarian limestone preserved a combination that complicated familiar categories. Archaeopteryx had feathers alongside skeletal...
Socrates refuses the comfortable defense
In Plato's account of the trial, Socrates defends the questioning that has made him unpopular. He presents himself as someone who exposes the distance between...
The landing is over before the news arrives
Curiosity's entry, descent, and landing took roughly seven minutes. Information from Mars took longer than that to reach Earth. The rover's landing system...
Two goods, four labor requirements
In his chapter on foreign trade, Ricardo described England and Portugal producing cloth and wine. His hypothetical Portugal needed less labor for either good....
A theory of unity during religious division
Bodin published his major political work in a kingdom fractured by religious conflict. Its account of sovereignty tried to identify what made a commonwealth a...
A calculation points a telescope
Irregularities in Uranus's observed motion led the mathematician Urbain Le Verrier to calculate where an unseen planet might be exerting a gravitational pull....
A disputed ancestry returns to print
The biologist later known as Lynn Margulis published a paper reviving the proposal that major cell structures descended from once-independent organisms....
Five hundred seats without five hundred campaigns
The Athenian Constitution describes a Council of five hundred, with fifty members chosen by lot from each of the ten tribes. The procedure combined randomness...
A lunar lander becomes a lifeboat
An oxygen tank failure in Apollo 13's service module forced the crew to abandon the planned Moon landing. The astronauts moved into the lunar module and used...
A guarantee arrives at the bank counter
After the banking crises of the Great Depression, federal deposit insurance began covering deposits at participating American banks. The initial limit was...
Closing the routes around the writ
The English Parliament enacted a law aimed at making an established remedy harder to evade. Its title addressed both the liberty of the subject and...
Stars beside a darkened Sun
During a total solar eclipse, British expeditions photographed stars near the Sun from Sobral in Brazil and the island of Príncipe. The darkened Sun made...
Pasteur sorts the mirror images
The young chemist Louis Pasteur examined a puzzling salt whose solution did not rotate polarized light as a related substance did. Looking closely, he found...
Themistocles on a broken pot
The Athenian statesman Themistocles helped make naval power central to his city's defense. Yet his military importance did not protect him from political...
Venus opens the road to Mercury
NASA's Mariner 10 passed Venus on February 5, 1974, gathering images and measurements while using the encounter to redirect its trajectory toward Mercury....
Apollo's shrinking horizon
After the first Moon landing, a presidential task group considered an expansive future: stations, a lunar base, and eventual human exploration of Mars. The...
Geometry beneath a prayer book
A scribe reused parchment containing a tenth-century copy of works by the Greek mathematician Archimedes. The leaves were cleaned, rearranged, and written...
Descartes' evil demon
In his 1641 Meditations, René Descartes set out to doubt everything he could, to find whatever survived as certain. He imagined an all-powerful “evil demon”...
Switching on the cortex
In 1949, Giuseppe Moruzzi and Horace Magoun published experiments in which they electrically stimulated the reticular formation in the brainstems of...
A scale for signals from the stars
In 1964 the Soviet radio astronomer Nikolai Kardashev published a paper on the transmission of information by extraterrestrial civilizations. To think clearly...
The essay at the NASA symposium
In 1993, the mathematician, computer scientist, and Hugo-winning novelist Vernor Vinge presented an essay, “The Coming Technological Singularity: How to...
The Green Bank meeting
In November 1961, the astronomer Frank Drake convened a small, invitation-only meeting at the National Radio Astronomy Observatory in Green Bank, West...
The monkeys that lost their fear
In the late 1930s, Heinrich Klüver and Paul Bucy removed large portions of the temporal lobes, including the amygdala, from rhesus monkeys at the University...
A fundraising sketch outlives its author
In the mid-1990s, Joseph P. Overton, a senior executive at Michigan's Mackinac Center for Public Policy, sketched a simple model to explain the think tank's...
The example that escaped the paper
In his 2003 paper on the ethics of advanced artificial intelligence, Nick Bostrom offered a brief illustration: a superintelligence whose only goal is to...
When relief became a tax
After monastic charity had been disrupted and poverty became a growing political concern, the Poor Relief Act of 1601 made every English parish responsible...
Heurēka in the bath
King Hiero of Syracuse suspected his goldsmith had cut the gold of a votive crown with silver, and asked Archimedes to find out without destroying it. In...
A Friday club builds a library
Books were scarce and costly in colonial Philadelphia. The Junto first pooled members' personal books, but the arrangement failed. Franklin then proposed a...
The growth of Athens, the fear of Sparta
In 431 BC the Greek world's two leading powers went to war for twenty-seven years. Thucydides, an Athenian general who lived through it, looked past the...
The Domesday survey
Twenty years after conquering England, William the Conqueror ordered a survey of his kingdom: who held every estate, from whom they held it, and what it was...
The eclipse that tested Einstein
Einstein's general relativity predicted that the Sun's gravity would bend the path of light from distant stars by a specific amount, about twice what Newton's...
The gadfly of Athens
For decades Socrates practiced dialectic in the open markets of Athens, cross-examining anyone reputed to be wise (politicians, poets, craftsmen) and showing,...
Dawn at the patron's door
Every morning in imperial Rome, clients in formal togas queued at their patron's door for the salutatio, the ritual greeting. In return for attendance, escort...
When defense looked dangerous
In 1972 the United States and Soviet Union agreed not to build nationwide defenses against strategic missiles. The logic was unsettling: if each side remained...
The bow that ended an embassy
Britain sent Lord Amherst to China seeking better trade relations and an audience with the Jiaqing emperor. Qing protocol required the kowtow, kneeling and...
Nine hours across open water
NBA player Kyle Korver had never used a stand-up paddleboard when Marcus Elliott proposed a twenty-five-mile crossing of the Santa Barbara Channel. Korver,...
Noon at Grand Central
In what he explicitly described as an unscientific sample, Schelling found an absolute majority converging on Grand Central Station's information booth and...
When the book became portable
In April 1501, just beyond the incunable cutoff, Aldus Manutius issued Virgil in a compact octavo volume. Many scholarly books were made for desks. Aldus's...
The black hole that was not black
Black holes were supposed to absorb everything and emit nothing. In 1974, Stephen Hawking calculated that quantum fields around an event horizon should...
When a chancellor knelt in Warsaw
West German Chancellor Willy Brandt traveled to Warsaw to sign a treaty accepting Poland's western border and normalizing relations after Nazi Germany's...
The paper that measured surprise
In 1948, Bell Labs researcher Claude Shannon published “A Mathematical Theory of Communication.” He treated a message not by what it meant, but by which...
The coup that destroyed the center
On August 19, eight senior officials declared that Gorbachev was ill, isolated him at his Crimean residence, and imposed emergency rule. Tanks entered Moscow....
Medea rises beyond Jason's reach
After Medea kills her children to punish Jason, he comes to confront her. She appears above him in a chariot sent by Helios, the sun god, with the bodies...
Why Webb circles an invisible point
Webb does not orbit Earth like Hubble. It orbits the Sun near L2, a moving balance point that travels with Earth. From there, the Sun, Earth, and Moon stay on...
Elektro promises a brighter future
At the 1939 New York World's Fair, Westinghouse presented Elektro as a friendly preview of tomorrow. The seven-foot humanoid walked, moved its arms, counted...
Quantitative easing begins
On November 25, 2008, as credit markets seized after Lehman's failure, the Federal Reserve announced purchases of up to $100 billion in agency debt and $500...
When free speech met the tanks
In 1968, Czechoslovak Communist leader Alexander Dubček led the Prague Spring, ending censorship and opening the press to public debate while promising reform...
Fourteen banks in one room
Long-Term Capital Management had lost most of its capital after Russia's default broke trades built on small price differences and vast leverage. The Federal...
Notes from the Danube frontier
Marcus Aurelius spent his last decade fighting the Marcomannic Wars on the Danube frontier, the empire's northern border, which followed the river through...
Trouble on the launchpad
On December 6, 1957, two months after Sputnik stunned the world, the United States attempted its first satellite launch, broadcast live. Vanguard Test Vehicle...
Say “shibboleth”
The Gileadites won the battle, then took the fords: the shallow stretches where the Jordan River could be waded across. It was the only way home for the...
The curve in the tax rolls
In the mid-1890s Vilfredo Pareto, an Italian engineer turned economist holding the chair at Lausanne, compiled income and tax records from England, Italy,...
Winners, victims, and a control group
In a 1978 study, psychologists Philip Brickman, Dan Coates, and Ronnie Janoff-Bulman interviewed three groups in Illinois: people who had recently won large...
The post that got deleted
In July 2010, the user Roko posted the basilisk argument to LessWrong, a forum devoted to rationality and AI. The site's founder, Eliezer Yudkowsky, reacted...