# Science and technology The history of scientific knowledge, machines, computation, medicine, and invention. *This story part of: How technology remade the world* *This story parallel: Forensic science: from fingerprints to junk science* *This story parallel: The history of science* *This story parallel: DARPA, Silicon Valley, and the security state* *How technology remade the world part of this story* *NASA and the space age part of this story* *The pillars of modern power part of this story* *Babylonian astronomy and the birth of the zodiac part of this story* *Forensic science: from fingerprints to junk science part of this story* *The history of mathematics part of this story* *The history of science part of this story* ## c. 10000 BCE — Agriculture and the Neolithic Revolution People began farming crops like wheat and barley and herding animals instead of only foraging. Farming led to permanent settlements, food surpluses, population growth and the rise of cities. ## c. 4500 BCE — The ard plough Farmers used a simple scratch plough pulled by animals to break soil for planting. The plough raised crop yields and let fewer people feed more. ## c. 3500 BCE — The wheel The wheel and axle appeared first for pottery and then for wheeled carts. It transformed transport, trade and machinery. ## c. 3300 BCE — Bronze metallurgy Smiths learned to alloy copper with tin to make bronze, a harder metal than either alone. Bronze tools and weapons defined an age and drove long distance trade in metals. ## c. 3200 BCE — Writing and cuneiform Sumerians pressed wedge shaped marks into clay tablets to record trade, laws and stories. Writing let knowledge outlast memory and is the foundation of recorded history. ## c. 3100 BCE — The sail Boats fitted with sails used wind power to travel rivers and seas. Sailing opened long distance trade and exploration by water. ## c. 1800 BCE — The alphabet Proto Sinaitic script reduced writing to a small set of signs for sounds rather than hundreds of symbols. This simple alphabet made literacy far easier to learn. ## c. 1601 BCE — Egyptian medicine and the Edwin Smith papyrus The surviving papyrus, copied from a much older text, treats injuries by observation and prognosis rather than by magic alone. It shows early empirical medicine sitting side by side with spells and ritual. Historians caution against reading it as fully rational science; healing in Egypt mixed careful observation with religion. ## c. 1200 BCE — Iron metallurgy Smiths mastered smelting and working iron, a common and strong metal. Iron tools and weapons spread widely because iron ore was far more plentiful than tin and copper. ## c. 1050 BCE — The Phoenician alphabet Phoenician traders spread a 22 letter consonant alphabet across the Mediterranean. It became the parent of the Greek, Latin, Hebrew and Arabic scripts. ## c. 701 BCE — Babylonian astronomers record the sky as numbers Scribes in Mesopotamia kept centuries of records of the moon, planets, and eclipses on clay tablets, and reduced their motions to arithmetic rules. This was proto-science, not modern science: the goal was omens and calendars, not physical laws. Yet the data and mathematical methods later fed directly into Greek astronomy. ## c. 600 BCE — First coinage The kingdom of Lydia struck the first standardized coins from electrum, a natural gold and silver alloy. Coined money made trade, taxes and wages easier to measure. ## c. 586 BCE — Thales and the first natural philosophers Thales and the Milesian thinkers began to explain the world through natural causes rather than the acts of gods, asking what everything was made of. The famous story that Thales predicted a solar eclipse is likely later legend. The lasting shift was the idea that nature follows understandable principles. ## c. 401 BCE — Hippocratic medicine separates disease from the divine The texts gathered under the name of Hippocrates argued that illness had natural causes and could be studied through observation of the patient. The works were written by many hands over generations, not one man. Their theory of four humors was wrong, but the method of careful bedside observation endured. ## c. 351 BCE — Aristotle's physics, four elements, and Earth at the center Aristotle built a vast system in which everything on Earth was made of earth, water, air, and fire, and the heavens turned around a motionless Earth. His work was a huge advance in systematic reasoning and biology, based on real observation of animals. It also fixed several wrong ideas, like geocentrism and objects needing a constant push to move, that would take almost two thousand years to overturn. ## c. 312 BCE — The Roman aqueduct Rome built long gravity fed channels to carry fresh water into cities, starting with the Aqua Appia. Aqueducts supplied baths, fountains and homes and supported large urban populations. ## c. 250 BCE — Archimedes screw A rotating screw inside a cylinder lifted water uphill with a simple turn of a handle. It was used to drain mines and irrigate fields and is still used today. ## c. 241 BCE — Eratosthenes measures the size of the Earth Using the different noon shadows cast at Alexandria and Syene, Eratosthenes estimated the Earth's circumference by simple geometry and got close to the true value. The exact figure depends on the length of his units, which we cannot pin down. The point stands: Greek science already knew the Earth was a globe and roughly how big. ## c. 200 BCE — Roman concrete Romans mixed volcanic ash, lime and water to make a durable concrete that could set underwater. It made possible domes, harbors and structures like the Pantheon that still stand. ## c. 200 BCE — The vertical waterwheel Waterwheels captured the energy of flowing water to grind grain and drive machinery. They were among the first machines to replace human and animal muscle with natural power. ## c. 50 BCE — Glassblowing Craftsmen learned to inflate molten glass with a blowpipe to shape vessels quickly. Glassblowing made glass affordable and common for the first time. ## c. 105 — Paper The official Cai Lun is credited with refining papermaking from pulped fibers into cheap writing sheets. Paper spread slowly westward and became the main surface for writing and printing. ## c. 150 — Ptolemy's Almagest codifies the geocentric universe Ptolemy gathered Greek astronomy into a mathematical model that predicted planetary positions using circles upon circles. It was geocentric and, in hindsight, wrong about the structure of the cosmos. But it worked well enough to guide navigation and calendars for over a thousand years, which is why it was so hard to displace. ## c. 600 — The stirrup Paired foot supports let a rider stay firmly seated and use weapons from horseback. The stirrup reshaped cavalry warfare across Asia and Europe. ## c. 700 — The windmill Vertical sail mills used wind to grind grain and pump water. Windmills gave regions without fast rivers a reliable source of mechanical power. ## c. 830 — The House of Wisdom gathers the world's learning in Baghdad Under Abbasid patronage, scholars in Baghdad translated Greek, Persian, and Indian works into Arabic and pushed them forward. The picture of a single grand library called the House of Wisdom is partly a modern simplification of a broader translation movement. Either way, this era preserved and advanced knowledge that Europe had largely lost. ## c. 850 — Gunpowder Chinese alchemists mixed saltpeter, charcoal and sulfur into an explosive powder. Gunpowder led to firearms and cannon and changed warfare worldwide. ## c. 1000 — The horse collar in Europe The padded collar, developed earlier in China, let horses pull heavy loads without choking. It made horses efficient for ploughing and hauling and boosted farm output. ## c. 1021 — Ibn al-Haytham and the experimental study of light In his Book of Optics, Ibn al-Haytham (Alhazen) showed that we see because light reflects from objects into the eye, overturning older Greek theories. He insisted on testing ideas against controlled observation, and many historians credit him as an early champion of the experimental method. The claim that he invented the scientific method single-handed is an overstatement, but his stress on evidence over authority was real and influential. ## c. 1025 — Ibn Sina's Canon of Medicine Ibn Sina (Avicenna) organized Greek and Islamic medicine into a single encyclopedic work that became a standard text in Europe and the Islamic world for centuries. It combined real clinical insight with the inherited humoral theory that was later abandoned. Its long reign shows both the strength and the danger of a single authoritative textbook. ## c. 1040 — Movable type printing Bi Sheng created reusable characters of fired clay to print pages. It was the first movable type, centuries before the same idea reshaped Europe. ## c. 1088 — The magnetic compass for navigation Sailors used a magnetized needle to find direction even without sight of the stars or shore. The compass made open sea navigation far more reliable and enabled long voyages. ## c. 1286 — Eyeglasses Unknown craftsmen near Pisa mounted two convex lenses in a frame to correct failing eyesight. Eyeglasses extended the working lives of scholars and artisans. ## c. 1300 — The mechanical clock European tower clocks using a verge escapement measured time with gears and a swinging bar instead of water. Mechanical clocks brought regular hours to towns and reshaped how people organized work and life. ## c. 1440 — Gutenberg's printing press Johannes Gutenberg develops printing with movable metal type around 1440. Cheap, fast reproduction of texts spreads literacy and new ideas, fueling the Reformation and the Scientific Revolution. ## 1543 — Copernicus places the sun at the center In On the Revolutions of the Heavenly Spheres, published the year he died, Copernicus put the sun at the center and set the Earth in motion. His system still used circular orbits and was not obviously more accurate than Ptolemy's at first. Its real power was conceptual: it made the sun-centered cosmos a serious scientific proposal. ## 1543 — Vesalius corrects the anatomy of the human body Vesalius published On the Fabric of the Human Body based on his own dissections, correcting many of Galen's long-accepted errors. His insistence on looking at the body directly, rather than trusting ancient texts, marked a turn toward evidence in medicine. The lavish illustrations spread the new anatomy across Europe. ## c. 1576 — Tycho Brahe builds the best pre-telescope observatory Tycho Brahe gathered decades of extremely precise naked-eye measurements of the planets and stars from his observatory at Uraniborg. He kept the Earth at the center in his own hybrid model, so he was not a Copernican. But his data, more accurate than anything before, became the raw material for a revolution he did not intend. ## c. 1600 — The compound microscope Dutch lens makers built early microscopes that magnified tiny objects. The microscope revealed cells and microbes and opened a hidden world to science. ## 1608 — The telescope Hans Lippershey filed for a patent on a device that made distant objects look nearer. Turned to the sky by Galileo, the telescope transformed astronomy and our view of the cosmos. > "This new system began with the first Puritan church at Salem, organized in 1629 by the so-called “Salem Procedure.”" > — Dumbing Us Down, p. 106-113 ## 1609 — Kepler's laws break the spell of the perfect circle Working from Tycho's data, Kepler found that planets move in ellipses, not circles, and sweep out equal areas in equal times. His third law, linking orbital period to distance, followed in 1619. He reached these results through years of grinding calculation, and mixed them with mystical ideas about cosmic harmony that historians are careful not to airbrush out. ## 1610 — Galileo turns the telescope on the heavens In Sidereus Nuncius, Galileo reported moons circling Jupiter, mountains on the moon, and countless unseen stars, all through a telescope he did not invent but greatly improved. These sights were hard to square with a perfect, Earth-centered heaven. He became the loudest public voice for the Copernican system. ## 1620 — Francis Bacon argues for knowledge from experiment In Novum Organum, Bacon called for building knowledge from careful observation and experiment rather than from ancient authority. He was a promoter and organizer of method more than a working scientist, and did little experimenting himself. His vision of collective, evidence-based inquiry helped inspire later scientific societies. ## 1633 — The trial of Galileo The Roman Inquisition tried Galileo for defending the sun-centered system and forced him to recant, sentencing him to house arrest. The clash was tangled up in Church politics, personality, and how he argued, not simply science against religion. It became a lasting symbol of the cost of challenging authority, and later a caution against reading all of history as that one story. ## 1637 — Descartes and reason as the path to knowledge In the Discourse on Method, Descartes argued for doubting everything and rebuilding knowledge on clear reasoning and mathematics. His mechanical picture of nature as matter in motion shaped how the next generation thought. Some of his specific physics was wrong, but his push for systematic method left a deep mark. ## 1656 — The pendulum clock Christiaan Huygens used a swinging pendulum to regulate a clock, making timekeeping far more accurate. Precise clocks aided science, navigation and daily coordination. ## 1687 — Newton's Principia unifies the heavens and the Earth In the Principia, Newton set out three laws of motion and a law of universal gravitation that governed both falling apples and orbiting planets. It fused Kepler's and Galileo's findings into one mathematical system and became the model of what a scientific theory could be. The tidy apple story is mostly legend; the work rested on years of hard mathematics and drew on many predecessors. ## 1701 — The seed drill Jethro Tull built a machine that planted seeds in neat rows at set depth. It cut waste and raised yields and was an early step toward mechanized farming. ## 1712 — Newcomen's atmospheric steam engine Thomas Newcomen built the first practical steam engine, used to pump water out of mines. It was the first machine to do useful work from steam and heat. ## c. 1764 — The spinning jenny James Hargreaves invented a machine that let one worker spin many threads at once. It was a key trigger of the mechanized textile industry. ## 1769 — Watt's improved steam engine James Watt added a separate condenser that made the steam engine far more efficient and fuel saving. His engines powered factories, mines and later transport and drove the Industrial Revolution. ## 1771 — Arkwright's factory system Richard Arkwright gathered water powered spinning machines and workers under one roof at Cromford Mill. This factory model of centralized, powered, wage labor production spread across industry. ## 1793 — The cotton gin Eli Whitney's machine quickly separated cotton fibers from their seeds. It made short staple cotton hugely profitable and deepened reliance on enslaved labor in the American South. ## 1796 — Vaccination Edward Jenner showed that inoculation with cowpox protected people against deadly smallpox. Vaccination founded immunology and has since saved hundreds of millions of lives. ## 1800 — The electric battery Alessandro Volta stacked discs of different metals to make the voltaic pile, the first steady source of electric current. The battery made controlled electricity possible and launched the study of electrochemistry. ## 1825 — The public railway The Stockton and Darlington Railway opened as the first public line to use steam locomotives, followed in 1830 by the Liverpool and Manchester Railway. Railways moved people and goods faster and cheaper than ever and reshaped cities and economies. ## 1839 — Photography Louis Daguerre announced the daguerreotype, a practical way to fix images from light onto a plate, building on earlier work by Niepce. Photography gave people a new way to record reality and later fed film, science and journalism. ## 24 May 1844 — The electric telegraph Samuel Morse sent the message What hath God wrought over a line from Washington to Baltimore. The telegraph let information travel almost instantly over long distances for the first time. ## 16 October 1846 — Surgical anaesthesia William Morton publicly demonstrated ether that let a patient sleep painlessly through surgery. Anaesthesia removed the agony of operations and made complex surgery possible. ## 1856 — The Bessemer process for steel Henry Bessemer devised a way to mass produce cheap steel by blowing air through molten iron. Abundant steel built railways, bridges, ships and skyscrapers. ## 1861 — Germ theory of disease Louis Pasteur showed that microbes cause disease and spoilage rather than arising on their own. Germ theory led to sterilization, safe food and modern public health. ## 1867 — Dynamite Alfred Nobel stabilized nitroglycerin into dynamite, a safer and controllable explosive. It transformed mining, tunneling and construction and also warfare. ## 1876 — The telephone Alexander Graham Bell patented a device that carried the human voice over an electric wire. The telephone let people talk across distances and grew into a worldwide network. > "It took thirty years to beat down a fierce oppo- sition, but by the 1880s it had come to pass — “they” had the children." > — Dumbing Us Down, p. 106-113 ## 1879 — The practical incandescent light bulb Thomas Edison developed a long lasting incandescent bulb suitable for everyday use. Electric light replaced flame and extended work and social life past sundown. ## 1882 — Central electric power station Edison's Pearl Street Station began supplying electricity to customers over a distribution grid. Central power stations made electricity a public utility and powered homes, industry and cities. ## 1885 — The automobile and internal combustion engine Karl Benz built the Patent Motorwagen, the first practical car driven by an internal combustion engine. The car reshaped transport, cities and daily life in the century that followed. ## 1895 — Radio Guglielmo Marconi built the first practical system for sending messages by radio waves without wires, followed by a transatlantic signal in 1901. Radio enabled wireless communication and later broadcasting to millions. ## 8 November 1895 — X-rays Wilhelm Roentgen discovered rays that could pass through the body and image bones on a plate. X-rays gave medicine its first way to see inside a living patient. ## 17 December 1903 — Powered flight The Wright brothers made the first sustained, controlled flight of a powered heavier than air machine. Aviation shrank the world and grew into global air travel and freight. ## 1905 — Einstein's special relativity In his miracle year, Einstein argued that the speed of light is constant for all observers, so space and time stretch and shrink with motion. The same year he explained the photoelectric effect and Brownian motion. He built on work by Lorentz and Poincare, who had some of the pieces but not the full reinterpretation. ## 1908 — The Ford Model T Henry Ford launched the Model T, a sturdy car simple enough to be affordable for ordinary families. It put millions on the road and made the automobile a mass product. ## 1913 — The moving assembly line Ford introduced a moving assembly line that brought the work to the worker and slashed the time to build a car. Mass production lowered prices and became the model for modern manufacturing. ## 1915 — Einstein's general relativity reshapes gravity Einstein recast gravity not as a force but as the bending of space and time by mass and energy. The theory predicted that starlight would bend around the sun, confirmed by an eclipse expedition in 1919 that made him famous overnight. It remains our best description of gravity and the large-scale universe. ## c. 1925 — Quantum mechanics remakes the rules of matter In the mid-1920s Heisenberg, Schrodinger, Born, Dirac, and others built quantum mechanics, in which particles behave as probabilities rather than certainties. It was the work of many hands over a few intense years, not a single breakthrough. Its predictions are astonishingly accurate, yet physicists still argue about what it really means. ## 1927 — Television Philo Farnsworth demonstrated a fully electronic television system that transmitted a moving image. Television became the dominant mass medium of the twentieth century. ## 1928 — Penicillin and antibiotics Alexander Fleming noticed that a mold killed bacteria, leading to penicillin, the first true antibiotic. Antibiotics made once fatal infections curable and transformed medicine. > "The most impressive statistic in French's study was a correlation coefficient of .82, which expressed the relationship between the composite rating of teaching ability and the measures of group attention during recitation periods." > — Life in Classrooms ## 1929 — Lemaitre and Hubble find an expanding universe Edwin Hubble's measurements showed that distant galaxies are rushing away from us, so the universe is expanding. The Belgian priest Georges Lemaitre had derived the expansion and proposed a primeval atom two years earlier, an idea that grew into the Big Bang. The name Big Bang was actually coined later by a skeptic, Fred Hoyle, as a jab. ## 1934 — Popper argues that science must be falsifiable Karl Popper argued that a theory is scientific only if it makes predictions that could in principle be proven wrong. This drew a line between science and claims that explain everything and risk nothing. Later philosophers, including Kuhn, argued that real science rarely works as cleanly as Popper's rule suggests. ## 1937 — The jet engine Frank Whittle ran the first bench test of a working turbojet engine. Jet propulsion led to fast, high flying aircraft and made mass air travel practical. ## 1938 — Nuclear fission Otto Hahn and Fritz Strassmann split the uranium atom, releasing energy, and Lise Meitner explained the result. Fission led to nuclear power and to nuclear weapons. ## 1945 — The ENIAC electronic computer ENIAC was among the first general purpose electronic digital computers, using thousands of vacuum tubes. It showed that machines could compute at electronic speed and pointed the way to the computer age. ## December 1947 — The transistor Researchers at Bell Labs built the first working transistor, a tiny solid state switch and amplifier. Transistors replaced bulky vacuum tubes and are the basic building block of all modern electronics. > "This technique, to which Bloom gave the term stimulated recall, consisted of making sound recordings of a class session and playing them back to the students within a period of two days from the actual event." > — Life in Classrooms ## 1953 — The double helix and the contested credit of Rosalind Franklin Watson and Crick worked out that DNA is a double helix, revealing how genetic information is copied and passed on. Their model depended heavily on Rosalind Franklin's X-ray images, shown to them without her clear consent, and she received little credit at the time. She had died before the 1962 Nobel Prize, which does not go to the dead, and the fairness of the credit is still debated. ## 1953 — The structure of DNA James Watson and Francis Crick, using data from Rosalind Franklin, described the double helix structure of DNA. It revealed how genes store and copy information and founded molecular biology. ## 1958 — The integrated circuit Jack Kilby built the first integrated circuit, placing multiple components on a single chip. The microchip made electronics small, cheap and powerful and enabled the digital world. ## 1960 — The contraceptive pill Regulators approved the first oral contraceptive pill for birth control. Reliable contraception gave women greater control over childbearing and reshaped families and society. ## 1960 — The laser Theodore Maiman built the first working laser, producing a narrow, intense beam of coherent light. Lasers now drive fiber optics, surgery, manufacturing, scanners and data storage. > "The point of view expounded here had its beginning in 1962 while I was a Fellow at the Center for Advanced Study in the Behavioral Sciences." > — Life in Classrooms ## 1962 — Kuhn and the idea of scientific revolutions Thomas Kuhn argued that science does not just accumulate facts but lurches between paradigms, with old frameworks replaced in crises. His book made paradigm shift a household phrase and challenged the tidy story of steady progress. Critics warned his view could be pushed too far, into treating all theories as equally valid, which he did not intend. ## 1962 — The communications satellite Telstar relayed the first live television and telephone signals across the Atlantic by satellite. Satellites now carry global communications, broadcasting and navigation. ## c. 1965 — Plate tectonics vindicates a drifting Earth Alfred Wegener had proposed drifting continents back in 1912, but was dismissed for lacking a mechanism. In the 1960s, seafloor spreading and magnetic stripes on the ocean floor supplied the missing engine, and plate tectonics became the framework of modern geology. It is a clear case of a rejected idea proven right once the evidence caught up. ## 29 October 1969 — ARPANET The first message was sent between computers on ARPANET, a packet switched network funded by the US military. ARPANET was the direct ancestor of the internet. ## c. 1970 — Peer review and science as a self-correcting process Formal peer review, where experts vet a paper before publication, became standard in most journals only in the middle of the twentieth century, later than many assume. It is a filter, not a guarantee of truth, and it misses errors and fraud. The deeper strength of science is that findings must survive repeated testing by others, so it corrects itself over time rather than resting on fixed truths. ## 1971 — The microprocessor Intel released the 4004, the first commercial microprocessor, putting a computer's processing on a single chip. Cheap microprocessors made personal computers, phones and countless devices possible. > "doing school work for the rewards it will bring in the form of good grades and teacher approval" > — Life in Classrooms > "Therefore, as perceived by their administrative superiors, these teachers comprise the top 5 or 10 percent of the instructional staff. The sample was drawn chiefly from suburban communities surrounding Chicago." > — Life in Classrooms > "In a sense he is working for the school and against it at the same time." > — Life in Classrooms > "The result, it is claimed, will be the transformation of teaching from an art to a science." > — Life in Classrooms ## 1973 — Recombinant DNA and genetic engineering Stanley Cohen and Herbert Boyer combined DNA from different organisms to make the first genetically engineered life. This launched biotechnology, from engineered insulin to modern gene medicine. ## c. 6 February 1973 — Construction begins on the CN Tower in Toronto Work started on the CN Tower, a concrete communications and observation tower for the Canadian National Railway. Crews used a slip-form technique to pour the shaft continuously as it rose. On completion in 1976 it stood 553 meters tall and became the world's tallest free-standing structure. ## c. February 1973 — France's Micral N ships as an early microcomputer The French firm R2E released the Micral N, a computer built around the Intel 8008 microprocessor and sold as a finished machine rather than a kit. It was first used to control processes such as highway toll systems. Many historians count it among the first commercial microcomputers. ## 7 March 1973 — Comet Kohoutek is discovered and billed as the comet of the century Czech astronomer Lubos Kohoutek discovers a bright new comet at the Hamburg Observatory. Found far from the Sun, it was predicted to become spectacularly bright and was hyped as the comet of the century. It underwhelmed skywatchers at the end of 1973, though the Skylab 4 crew and other scientists studied it closely. ## c. March 1973 — The Xerox Alto brings the graphical desktop to life Xerox PARC put its first Alto computer into operation, a machine built around a bitmapped screen, a mouse, and windows. It was among the earliest computers designed for one person to use with a graphical interface. The Alto's ideas later shaped the Apple Macintosh and modern personal computing. ## 3 April 1973 — Martin Cooper places the first handheld mobile phone call Motorola engineer Martin Cooper stood on a Manhattan street and made the first public call from a handheld cellular phone, a prototype that weighed about a kilogram. He phoned Joel Engel, his rival at Bell Labs. The demonstration proved that personal, portable phones were possible. ## 3 April 1973 — The handheld mobile phone Martin Cooper of Motorola made the first public call from a handheld cellular phone, the DynaTAC prototype. The first consumer model reached the market in 1983 and mobile phones went on to reach most of humanity. ## 4 April 1973 — The World Trade Center towers open in New York The Twin Towers of the World Trade Center were dedicated in Lower Manhattan after years of construction. At 110 stories, the North Tower briefly ranked as the tallest building in the world. The complex, designed by Minoru Yamasaki, reshaped the city's skyline until its destruction in 2001. ## 6 April 1973 — Pioneer 11 launches toward Jupiter and Saturn NASA launches the Pioneer 11 probe on a mission to the outer planets. It would fly past Jupiter in 1974 and become the first spacecraft to reach Saturn, in 1979. Like its twin Pioneer 10, it carried a plaque meant to describe humanity to any future finder. ## 3 May 1973 — The Sears Tower tops out as the world's tallest building Ironworkers bolted the final beam into place on the Sears Tower in Chicago, bringing it to 442 meters and 110 stories. It passed the World Trade Center to become the tallest building in the world. The tower, now called Willis Tower, held that record for nearly 25 years. ## 14 May 1973 — Skylab, America's first space station, reaches orbit damaged NASA launches Skylab, the first American space station, on the last flight of a Saturn V rocket. During ascent the micrometeoroid and thermal shield tore away, ripping off one main solar wing and jamming the other, which left the station overheating and short of power. The orbital workshop reached orbit but could not be occupied until it was repaired. ## 22 May 1973 — Robert Metcalfe describes Ethernet at Xerox PARC Robert Metcalfe circulated a memo at Xerox's Palo Alto Research Center laying out a scheme to link computers over a shared cable, which he named Ethernet. Working with David Boggs, he built the system to connect the lab's Alto workstations to a laser printer. Ethernet became the dominant standard for wired local area networks. ## 25 May 1973 — Skylab's first crew saves the crippled station Astronauts Charles Conrad, Paul Weitz and Joseph Kerwin fly to Skylab and rescue it in orbit. They deployed a parasol sunshade to cool the overheated workshop and freed the jammed solar wing during a spacewalk, restoring power. The crew spent 28 days aboard, then a record for human spaceflight, proving that astronauts could repair large structures in space. ## c. June 1973 — Cosmic gamma-ray bursts are revealed to science Scientists at Los Alamos publish the discovery of gamma-ray bursts, brief and powerful flashes of gamma rays from deep space. The bursts had been recorded years earlier by the Vela satellites, which were built to watch for secret nuclear weapon tests. The finding opened a new field of high-energy astrophysics whose origin stayed a mystery for decades. ## c. July 1973 — CERN's Gargamelle experiment finds weak neutral currents Physicists working with the Gargamelle bubble chamber at CERN report the first evidence of weak neutral currents, a form of the weak nuclear force that leaves particles unchanged in charge. The result confirmed a central prediction of the emerging electroweak theory of Glashow, Weinberg and Salam. It was a milestone in building the Standard Model of particle physics. ## 30 October 1973 — The Bosphorus Bridge opens linking Europe and Asia The Bosphorus Bridge opened in Istanbul, the first bridge to span the strait between the European and Asian sides of the city. The suspension bridge stretched over a kilometer across the water. Its opening on the 50th anniversary of the Turkish Republic joined the two continents by road for the first time. ## 3 November 1973 — Mariner 10 launches on the first mission to Mercury NASA launches Mariner 10, bound for Venus and Mercury. It was the first spacecraft to use a gravity assist, swinging past Venus to reach Mercury, and the first to visit two planets on one mission. It returned the first close-up images of Mercury during three flybys in 1974 and 1975. ## 16 November 1973 — Skylab 4 crew sets an 84-day endurance record Gerald Carr, Edward Gibson and William Pogue launch on the third and final crewed Skylab mission. They stayed in orbit for 84 days, a human spaceflight duration record that stood for years, and studied the Sun and the newly found Comet Kohoutek. The mission also saw the crew push back against an overloaded schedule set by ground control. ## c. November 1973 — Cohen and Boyer create the first recombinant DNA organism Stanley Cohen of Stanford and Herbert Boyer of the University of California, San Francisco report splicing genes from one organism into a bacterial plasmid that then replicated in E. coli. Published in the Proceedings of the National Academy of Sciences, the work showed genes could be cut, joined and cloned at will. It launched genetic engineering and the biotechnology industry. ## 3 December 1973 — Pioneer 10 makes the first flyby of Jupiter Pioneer 10 becomes the first spacecraft to fly past Jupiter, passing about 130,000 kilometres above the cloud tops. It sent back the first close-up images of the giant planet and measured its intense radiation belts, proving a probe could survive them. The mission was run from NASA's Ames Research Center in California. ## 10 December 1973 — The founders of ethology win the Nobel Prize in Medicine Karl von Frisch, Konrad Lorenz and Nikolaas Tinbergen share the Nobel Prize in Physiology or Medicine for their study of animal behaviour. Their work covered the honeybee's dance language, imprinting in young animals and the instinctive triggers of behaviour. It was the first Nobel awarded for the science of ethology. ## c. 1973 — Cerf and Kahn design TCP for internetworking Vint Cerf and Robert Kahn worked out the Transmission Control Program, a way to join separate packet networks into one network of networks. The design let different networks pass data through common gateways without knowing each other's internals. This work became the foundation of the modern Internet's TCP/IP protocols. ## c. 1973 — Community Memory opens the first public computer bulletin board A group in Berkeley set up Community Memory, placing a computer terminal in a record store so ordinary people could post and read messages. It let strangers share notices, find rides, and trade goods through a shared database. It was one of the first attempts to use computers as a public communication network. ## 1975 — The personal computer The Altair 8800 kit sparked the personal computer movement, followed by ready to use machines like the Apple II in 1977. Personal computers put computing power on ordinary desks and in homes. ## c. 1975 — The Standard Model and the Higgs boson Through the 1960s and 1970s physicists assembled the Standard Model, describing the known particles and three of the four fundamental forces. Its final missing piece, the Higgs boson, was predicted in 1964 and detected at CERN in 2012. The model is our most tested theory, yet it leaves out gravity and dark matter, so the work is unfinished.