3,147 short facts, ideas and puzzles from books, papers and primary sources. No filler, and every card credits where it came from. Free, right in your browser, with a daily word game and playable puzzles.
Start swiping — it's freeIn 1928, Paul Dirac's equation unifying quantum mechanics and relativity produced a strange extra solution: a particle identical to the electron but positively charged. Most physicists assumed it was a flaw in the math. In 1932, Carl Anderson photographed exactly such a particle in cosmic-ray tracks, confirming antimatter was real.
— Carl D. Anderson, The Positive Electron — Physical Review, 1933
Emily's father has three daughters. The first is named April, the second is named May. What is the third daughter's name?
Emily. The question tells you her name in its very first sentence — but the pattern 'April, May, ...' primes an automatic, wrong answer ('June') that most people blurt out before rereading the sentence. It's one of four items on the CRT-2, a less math-heavy alternate version of the Cognitive Reflection Test built by psychologists Keela Thomson and Daniel Oppenheimer to catch the same snap-judgment-versus-reflection failure as the original bat-and-ball question, without requiring any arithmetic.
In this 12th-century philosophical tale, a child grows up alone on a deserted island, raised by a gazelle, and reconstructs the truths of nature, ethics and eventually theology purely through solitary observation and reasoning, without any teacher, language or revealed scripture. The story influenced later empiricist thinkers and prefigures Robinson Crusoe.
Operation Paperclip brought German scientists and engineers — some former Nazi party members, including rocket designer Wernher von Braun — to the United States after World War II, often sanitizing their records to get them past immigration law. Many went on to shape the US space and missile programs for decades.
— Wikipedia contributors, Operation Paperclip — Historical record
Bouvet Island, a Norwegian dependency in the South Atlantic, sits about 1,700 km from the nearest land, Antarctica's Queen Maud Land, and roughly 2,260 km from the nearest inhabited place, Tristan da Cunha. Nearly all of its 49 square km lie buried under glacial ice, visited only by automated research equipment and occasional scientific expeditions.
— Standard geographic accounts, Bouvet Island — Norwegian dependency, South Atlantic Ocean