Ikigai Daily
Menu
WonderScience fact

NASA's Pioneer 10 and 11 space probes, launched in 1972 and 1973, each carry a small gold-anodised aluminium plaque showing a man, a woman and a map of where the probe came from. They were the first messages deliberately sent on spacecraft bound to leave the Solar System.

Pioneer plaque

ScienceArtSpaceHistory

The story behind the card

Carl Sagan and Frank Drake designed the plaque, about 23 by 15 centimetres, and Linda Salzman Sagan drew the figures. Its key is hydrogen, the most common element in the universe: a hydrogen atom can flip between two energy states and give off radiation of a fixed wavelength, about 21 centimetres, which offers any finder a universal unit of length and time. Using that unit, a map shows the Sun's position relative to 14 pulsars, collapsed stars that spin and send out radio pulses at precise, recognisable rates. The nude figures drew complaints, and some newspapers censored them. The plaques are mounted where the probes shield them from interstellar dust. Voyager 1 and 2 followed in 1977, carrying the more elaborate Golden Record.

Türkçe oku
NASA'nın 1972 ve 1973'te fırlattığı Pioneer 10 ve 11 sondaları, Güneş Sistemi'nin dışına bilerek mesaj götüren ilk uzay araçlarıdır. Her birinde altın rengi alüminyumdan küçük bir plaka var: Üzerinde bir kadın, bir erkek ve sondanın nereden geldiğini gösteren bir harita çizili.

Plakayı Carl Sagan ile Frank Drake tasarladı; yaklaşık 23'e 15 santimetrelik plakadaki insan figürlerini Linda Salzman Sagan çizdi. Plakanın anahtarı, evrendeki en yaygın element olan hidrojendir. Bir hidrojen atomu iki enerji durumu arasında geçiş yapabilir ve bu sırada dalga boyu hep aynı, yaklaşık 21 santimetre olan bir ışıma yayar. Bu da plakayı bulacak herkese evrensel bir uzunluk ve zaman birimi sunar. Bu birimle çizilen bir harita, Güneş'in konumunu 14 pulsara göre gösterir. Pulsarlar, kendi etrafında dönen ve belirli, tanınabilir aralıklarla radyo sinyali yayan çökmüş yıldızlardır. Çıplak insan figürleri tepki çekti, bazı gazeteler resmi sansürledi. Plakalar, sondanın onları yıldızlararası tozdan koruyacağı bir yere takıldı. 1977'de fırlatılan Voyager 1 ve 2 ise çok daha kapsamlı Altın Plak'ı taşıdı.

Sources and further reading

Background reading: Pioneer plaque
Get the mobile appAbout our cards

Related cards

These cards share a subject or reading mode with the card above.

WonderBiography

American astronomer Annie Jump Cannon sorted about 350,000 stars at Harvard by the pattern of dark lines in their light. Her classes, O, B, A, F, G, K and M, running from the hottest stars to the coolest, are still the standard way to group stars.

Cannon was one of the “Harvard computers”, a team of women hired to study photographs of the night sky on glass plates, often for about 25 cents an hour. When starlight is spread into a spectrum, a band of colours, dark lines appear that are left by the elements in the star. Earlier schemes used many letters; Cannon reordered and simplified them into one clear sequence, and in 1925 Cecilia Payne used her data in work showing that the sequence follows temperature. Nearly deaf after an illness, Cannon worked at legendary speed, classifying up to three stars a minute, and her results filled the Henry Draper Catalogue, published between 1918 and 1924. In 1925 she became the first woman to receive an honorary doctorate of science from Oxford University.

Annie Jump CannonRead card
WonderScience

A cloud chamber makes invisible charged particles visible: as one passes through air loaded with vapour, it leaves a trail of tiny droplets, like the vapour trail of a jet. Scottish physicist Charles Wilson invented it, and its photographs helped reveal new particles.

Wilson's idea began on the summit of Ben Nevis in 1894, where rings of coloured light around shadows cast on cloud made him want to recreate clouds in the laboratory. In his chamber, a sudden expansion cools moist air until the vapour is on the point of turning into droplets. A passing charged particle knocks electrons off air molecules, leaving a line of charged atoms, or ions, on which droplets form. He photographed the first tracks in 1911. With a magnet around the chamber the tracks curve, and the direction and tightness of each curve reveal a particle's charge and momentum. In 1932 Carl Anderson used such tracks to discover the positron, the first known particle of antimatter. Wilson shared the 1927 Nobel Prize in Physics for the chamber.

Cloud chamberRead card
WonderArt

In the late 1800s, photographers learned to split movement into a rapid series of still pictures, a technique called chronophotography, and scientists could at last measure how people and animals walk, run and fly. Eadweard Muybridge and Étienne-Jules Marey were its pioneers.

In June 1878, at Leland Stanford's farm in Palo Alto, California, Eadweard Muybridge set up a row of cameras that fired one after another as a horse galloped past. His pictures of the mare Sallie Gardner settled a long debate: a galloping horse does lift all four hooves off the ground at once, but with its legs tucked beneath it, not stretched out fore and aft as painters had shown. In 1882 the French physiologist Étienne-Jules Marey built a rifle-shaped camera that took twelve pictures a second, and he developed ways of recording successive phases of a movement on a single plate, so a walking man or a flying bird became one layered image. From 1880 Muybridge projected his sequences as moving pictures with his zoopraxiscope, and both men's work fed into the birth of cinema.

ChronophotographyRead card
DriveHistory

In 1960–61, thirteen American women pilots, later known as the Mercury 13, passed the same first-phase medical tests that physician William Randolph Lovelace had helped design for NASA's first male astronauts. The private project was never an official NASA selection and was stopped before they could go further.

Lovelace began in 1960 with the record-setting pilot Jerrie Cobb, who passed all three phases of testing and ranked in the top 2% of candidates of either sex; she then helped him find the other women, and the aviator Jacqueline Cochran paid for much of the work. NASA, however, required its first astronauts to be military jet test pilots with a degree in engineering or the equivalent, and women could not train as military test pilots. In July 1962 Cobb and fellow pilot Jane Hart asked a congressional subcommittee to let the testing continue; astronaut John Glenn argued against it, and nothing changed. The name “Mercury 13” was coined in 1995. Sally Ride became the first American woman in space in 1983, and in 2021 Wally Funk, one of the thirteen, finally flew to space at 82.

Mercury 13Read card
WonderLiterature

Mark Twain was born on 30 November 1835, two weeks after Halley's Comet swung round the Sun. In 1909 he said he expected to go out with it. He died on 21 April 1910, one day after the comet's next closest pass.

According to his biographer Albert Bigelow Paine, Twain said in 1909: 'I came in with Halley's comet in 1835. It is coming again next year, and I expect to go out with it.' He described himself and the comet as 'two unaccountable freaks' that had come in together and must go out together. The dates are the comet's perihelions, its closest passes to the Sun, and they frame his life almost exactly: he was born a fortnight after one and died a day after the next. Halley's Comet returns roughly every 76 years; it is next due in 2061.

Mark Twain and Halley's CometRead card
Next card in the archiveIce drilled from Antarctica holds an unbroken record of Earth's climate going back at least 1.2 million years. The European Beyond EPICA team reached bedrock at Little Dome C, about 2.8 kilometres down, in January 2025; the top 2,480 metres can be read in order, while the deepest ice is deformed.Read next →