Cepheids as cosmic markers
Henrietta Leavitt discovers that brighter Cepheid variable stars blink slower than dimmer ones, a relationship that gave astronomers a way to measure cosmic distances.
Henrietta Leavitt discovers that brighter Cepheid variable stars blink slower than dimmer ones, a relationship that gave astronomers a way to measure cosmic distances.
An amateur archaeologist reports finding fossils of a human ancestor near Piltdown, England. Piltdown Man is touted as evidence that a big brain evolved early in human evolution, but the fossils are later exposed as a hoax.
Meteorologist Alfred Wegener suggests that Earth’s continents aren’t fixed in place, but drift around the globe.
Geologist Arthur Holmes publishes The Age of the Earth, presenting the first complete geologic timescale and arguing for using radioactive materials as geologic clocks.
Harlow Shapley and Heber Curtis publicly debate whether “island universes” – what we now call galaxies – exist outside the Milky Way.
Miners in what’s now Zambia unearth a roughly 300,000-year-old humanlike skull. Known as the Kabwe or Broken Hill skull, it’s the first ancient hominin fossil discovered in Africa.
Psychoanalyst Sigmund Freud, shown, describes mental life as a series of conflicts between a person’s primitive instincts, or id, and moral conscience, or superego, mediated by the ego’s considerations of what’s socially acceptable.
Two scientists at Washington University of St. Louis, Edgar Allen and Edward Doisy, first isolated estrogen in experimental mice and found that it was produced in the ovaries.
Russian physiologist Ivan Pawlow (Pavlov) reports that mice learn to associate an electric bell with dinner after 300 lessons of the bell accompanying food.
The discovery in South Africa of a 2.8-million-year-old skull with a blend of apelike and humanlike traits hints that the earliest phases of human evolution happened in Africa. Raymond Dart, shown with the fossil, called the Taung Child, places it into a new genus: Australopithecus.
Edwin Hubble measures the distance to the Andromeda nebula, showing it is in fact another galaxy. The Milky Way is not the entire universe.
Cecilia Payne (shown) discovers what stars are made of: mostly hydrogen and helium.
William D. Harkins achieves transmutation of elements, converting nitrogen to fluorine and then to hydrogen and oxygen by bombarding the starting element with a helium nucleus. A German physicist later hits gold with hydrogen to make mercury.
Based on a tooth found at China’s Zhoukoudian site, Davidson Black identifies a new hominin species named Sinanthropus pekinensis (now called Homo erectus) that lived several hundred thousand years ago.
The discovery of a flint point alongside the remains of prehistoric buffalo in Folsom, N.M., helps convince anthropologists that humans have lived in the Americas since the Ice Age.
Anthropologist Margaret Mead’s book Coming of Age in Samoa controversially argues that casual sexuality and other cultural practices on a South Pacific island make adolescence smoother for girls there than girls in Western cultures.
Geologist Arthur Holmes proposes that heat from the radioactive decay of elements in the Earth keeps the planet’s interior partially molten.
German psychiatrist Hans Berger reports the first human electroencephalogram, or EEG.
Edwin Hubble (shown) reports that distant galaxies appear to be flying away from us faster than nearby galaxies, crucial evidence that the universe is expanding.
Clyde Tombaugh (shown) spots a new object orbiting the sun past Neptune. Pluto, predicted 25 years earlier by Percival Lowell, would be considered the ninth planet until 2006.
The electron microscope is invented by Max Knoll and Ernst Ruska (shown), allowing for the investigation of a wide range of materials, including biological samples.
In his book The Moral Judgment of the Child, developmental psychologist Jean Piaget argues that children develop moral ideas in three broad stages largely via interactions with peers.
Pioneering memory researcher Frederic Bartlett publishes experiments showing that what people remember about past events consists of a mix of fact and culturally influenced fill-ins.
Physicist James Chadwick discovers an electrically neutral particle, the neutron, contained within atomic nuclei.
Images from physicist Carl Anderson’s cloud chamber reveal a positively charged particle with a mass equivalent to the electron: a positron.
Karl Jansky’s discovery of a shortwave radio hiss coming from the Milky Way’s heart is widely publicized, marking the beginning of radio astronomy. Jansky is shown here with his rotating radio antenna.
Fritz Zwicky examines galaxies in the Coma cluster and determines that there is unseen mass, what scientists now call “dark matter.”
Harvard researchers Gregory Pincus and E.V. Enzmann grow rabbit eggs cells to maturity in the laboratory for the first time.
Henry Dale reports the discovery of acetylcholine, a chemical released by nerves to command a muscle to move.
The first artificially produced radioactive isotopes are discovered by Frédéric and Irène Joliot-Curie.
Neurosurgeon Wilder Penfield reports on an epilepsy treatment, now known as the “Montreal Procedure,” that destroys areas of the brain where seizures begin.
Scientists use electroencephalography to show that two types of electrical waves, labeled alpha and beta, occur in the brain.
The Richter scale is proposed by seismologist Charles Richter (shown) to compare the magnitude of different earthquakes. The more accurate moment magnitude scale is now used for most earthquakes.
Seismologist Inge Lehmann discovers that Earth has a solid inner core, distinct from its molten outer core.
In South Africa, Robert Broom identifies a robust form of hominin, named Paranthropus robustus, that had giant molar teeth and a skull built for heavy chewing. The species, now known to have lived 1.8 million to 1.2 million years ago, is evidence that more than one type of hominin once called the region home.
Nuclear physicist Hans Bethe describes how hydrogen atoms inside stars combine to form helium, releasing vast amounts of energy in the process.
Psychologist B.F. Skinner, shown, presents evidence indicating that behaviors are strengthened or weakened by their consequences in his first book, The Behavior of Organisms.
In a discovery that portends the possibility of atomic bombs, Otto Hahn (right) and Fritz Strassmann report evidence that uranium atoms produce barium when bombarded with neutrons. As explained by their collaborator Lise Meitner (left) and her nephew Otto Frisch, this is fission, the splitting of atoms.
Physicists Maria Goeppert Mayer and J. Hans D. Jensen develop a theory of the nucleus as composed of shells of protons and neutrons. It explains why nuclei with certain “magic numbers” of protons and neutrons are more stable.
After creating large amounts of carbon-14 using a cyclotron, or “atom-smasher,” researchers hail the isotope’s potential as a medical tracer. In 1949, Willard Libby and colleagues demonstrate that radioactive carbon can be used to measure the age of organic objects like fossils. The technique works on samples up to about 50,000 years old.
Physicists in the United States produce the first controlled, self-sustaining nuclear chain reaction, in a major step toward an atomic bomb.
With the formation of the Manhattan Engineer District, the United States kick-starts a massive project to build an atomic bomb, which employed more than 120,000 people at its peak.
Details of an epidural nerve block that allows pain-free childbirth without putting women to sleep are reported.
Leo Kanner reports on his studies of a mental illness in 11 children that causes them to largely ignore the people around them, a disease that would come to be called autism.
In July, the United States tests the atomic bomb in the New Mexico desert. In August, the U.S. drops two bombs on Japan, killing more than 100,000 people and hastening the end of World War II.
Physicist Walter M. Elsasser and geophysicist Edward Bullard separately propose between 1946 and 1949 that Earth’s magnetic field is a self-sustaining dynamo generated by the movement of fluid in the liquid outer core, which produces an electric current.
J. Lawrence Pool is the first to implant electrodes into a woman with Parkinson’s disease.
Canadian psychologist Donald Hebb publishes his account of how neurons reinforce each other’s activity, a description that’s now shorthanded, “fire together, wire together.”
William W. Morgan and colleagues present a model of the Milky Way’s shape made of cotton balls to the American Astronomical Society meeting, depicting the galaxy as a spiral. The team received a raucous ovation with stomping feet.
Rita Levi-Montalcini identifies chemicals from mouse tumors that stimulate growth in chick embryos — the discovery of nerve growth factor.
The United States tests the first hydrogen bomb, a thermonuclear weapon 1,000 times more powerful than the bomb dropped on Hiroshima.
A patient known as H.M. undergoes surgery to remove his hippocampus, later revealing the role that the brain structure plays in memory. Studies of his postmortem brain (shown) complicated the picture.
Physiologists Nathaniel Kleitman and Eugene Aserinsky report the discovery of rapid eye movement during sleep and link it to dreams.
Scientists report that chlorpromazine, developed to treat nausea and vomiting, also helps sedate mental patients.
Psychologist George Miller reports that people can typically hold no more than about seven types or pieces of information in short-term memory, a capacity Miller dubbed “the magical number seven, plus or minus two.” He publishes the work the next year.
Donald Glaser reports on the first photographs taken with his new bubble chamber, a tool for recording collisions of subatomic particles.
Geochemist Clair Patterson sets the age of the Earth at 4.550 billion years, relying on ages of meteorites (including the Canyon Diablo meteorite, shown) that formed around the same time.
Scientists detect the neutrino, an electrically neutral subatomic particle released in radioactive decay and other reactions. It had once been thought to be undetectable.
A decision-making model developed by economist Herbert Simon contends that people use experience-based rules of thumb to work around limited knowledge and time when dealing with complex challenges, such as playing chess.
Columbia University researchers Bruce Heezen, Marie Tharp (shown) and Maurice Ewing create the first comprehensive map of an ocean basin, revealing a deep rift right at the center of a long underwater mountain chain cutting through the North Atlantic.
Particles that are mirror images — those with opposite “handedness” or orientation of their spin — don’t necessarily behave identically. Chien-Shiung Wu and colleagues report the discovery of this phenomenon, called parity violation, in decays of cobalt-60 atoms.
President Eisenhower signs legislation establishing the National Aeronautics and Space Administration, better known as NASA.
At Olduvai Gorge in Tanzania, Mary Leakey finds the skull of a robust hominin. She and her husband, Louis Leakey, name it Zinjanthropus boisei (now called Paranthropus boisei). The discovery shifts the focus of hominin fieldwork to East Africa.
In a widely cited book review, linguist Noam Chomsky criticizes B.F. Skinner’s view of language as learned behavior and suggests that human speech springs from an innate grammar capacity.
David Hubel and Torsten Wiesel illuminate the visual system in the cat, opening up an area of inquiry for how brain systems handle information from the senses.
Frank Drake aims a radio telescope (the Tatel Telescope in Green Bank, W.Va., shown) at two stars to listen for signs of alien civilizations, the first SETI experiment.
The U.S. Food and Drug Administration approves the first oral contraceptive, soon known simply as “the pill.”
Geologists use a radiometric dating technique to estimate a true date, rather than a relative age, for an ancient hominin fossil.
Soviet cosmonaut Yuri Gagarin becomes the first human to orbit the Earth.
Experimental studies of people’s willingness to follow orders to administer what they think are electric shocks to an unseen stranger gain fame and notoriety for social psychologist Stanley Milgram (Milgram’s “shock box” is shown).
The first cochlear implants, which translate sounds into electrical stimulation, are implanted in deaf patients, in Los Angeles.
Geologist Harry Hess and geophysicist Robert S. Dietz independently argue in 1961 and 1962 that the seafloor is pulling apart at mid-ocean ridges.
Geophysicist J. Tuzo Wilson suggests that volcanic island chains form as plates move over upwellings of magma in the mantle.
Observations by Jane Goodall (shown) of wild chimpanzees using twigs to fish for termites and leaves to soak up water shock anthropologists who thought toolmaking was a defining trait of humans.
Louis Leakey and colleagues report that a collection of fossils found at Tanzania’s Olduvai Gorge are the earliest known remains from the genus Homo. The researchers fold the fossils into a new species, Homo habilis, thought to have lived about 2.4 million to 1.4 million years ago. The classification remains controversial.
Marian Diamond provides early evidence for the brain’s ability to change, or plasticity, later summarizing her findings with the phrase, “Use it or lose it.”
Arno Penzias (left) and Robert Wilson (right) discover the cosmic microwave background radiation, the relic radiation left over from the Big Bang.
Astronomers describe 12 strange celestial objects that appear a bit like stars and a bit like galaxies as quasars, for quasi-stellar radio sources.
The NASA Mariner 4 spacecraft takes the first photos of another planet from space.
Beatrice Mintz creates a mouse with two mothers and two fathers to demonstrate which parent’s genetic contribution ended up in which region of the body.
The Soviet Luna 9 spacecraft makes the first soft landing on the moon.
Norwegian physiologist Terje Lømo observes that connections between nerve cells strengthen with use, a core principle of neuroscience called long-term potentiation.
Harry Whittington (shown) leads an expedition to Canada’s Burgess Shale, identifying a riot of new and unusual forms of animal life and boosting studies into the Cambrian explosion.
By studying blood proteins, Vincent Sarich and Allan Wilson develop a “molecular clock” for primate evolution. The pair estimates that humans and African apes diverged about 5 million years ago. The latest estimates suggest that humans and chimpanzees, now known to be our closest living relative, diverged sometime between 9 million and 6 million years ago.
The great unifying theory of the earth sciences is born with the publication of two separate studies, one by geophysicist W. Jason Morgan in 1967 and the other by geophysicists Dan McKenzie and Robert Parker in 1968.
The first pulsar — stellar objects emitting beams of radiation that look from Earth like pulses — is discovered by Jocelyn Bell Burnell.
The idea that modern birds evolved from dinosaurs takes hold, with new evidence of warm-bloodedness and fossil discoveries such as the small, carnivorous Deinonychus antirrhopus.
Apollo 11 astronauts Neil Armstrong and Buzz Aldrin (shown) become the first people to walk on the moon.
Scientists report for the first time test-tube fertilization of human eggs.
Eric Kandel shows how synapses change in response to learning, early work that led to a greater understanding of short- and long-term memory.
Mariner 9 orbits Mars, sending home pictures of a global dust storm.
Studying baker’s yeast, geneticist Leland H. Hartwell identifies genes that regulate how cells divide as well as proteins that halt division if a cell’s DNA is damaged.
The first detailed image of a living brain is taken by a computerized tomography, or CT, scanner in England. Co-inventor of the technology, Godfrey Hounsfield, is shown.
Studies of radio emissions from Cygnus X-1 support claims that it is a black hole, the first detected black hole candidate.
The first Landsat satellite launched (shown), opening the door to continuous monitoring of Earth and its features from above.
Michael E. Phelps and colleagues invent a technique for seeing radioactive tracers in the living brain called positron emission tomography, or PET.
Two teams of physicists find a new subatomic particle, the J/psi, which, it soon became clear, could be explained only by a new type of quark, the charm quark. This discovery and others during the period, known as the November revolution, quelled lingering doubts that quarks were real constituents of larger particles such as protons, neutrons and the J/psi.
Astronomers William Hartmann and Donald Davis propose in 1975 the Giant Impact Hypothesis, suggesting the moon formed out of material ejected from Earth after a large collision. Space scientist Alastair Cameron and astronomer William Ward developed the same idea independently, proposing it in 1976.
The first spacecraft to survive on Mars for an extended time looked for signs of life, but its results were inconclusive.
Scientists find that Earth’s ice ages over the last 500,000 years correlate to three different orbital variations — cycles lasting about 23,000 years, 42,000 years (now said to be 41,000) and 100,000 years, confirming a hypothesis proposed decades earlier by astronomer Milutin Milankovitch.
Two spacecraft head to the outer reaches of the solar system, eventually passing all the giant planets and leaving the solar system altogether.
Dives to the seafloor along the Galápagos Rift reveal the first known active hydrothermal vent — and abundant life (including this purple octopus at one vent site).
Fossilized footprints at the Tanzanian site of Laetoli (shown) reveal that by 3.6 million years ago hominins were already competent upright walkers.
Psychologist Francine Patterson reports that Koko, a “talking” gorilla, has a sign language vocabulary of 375 words (Patterson and Koko are shown). Two chimps exhibit “the first instance of symbolic communication between nonhuman primates.”
Louise Brown is the first baby born using in vitro fertilization.
Work reported by Edward Lewis in 1978 and Christiane Nüsslein-Volhard and Eric Wieschaus in 1980 reveals which genes control early embryonic development in fruit flies. The discoveries help explain congenital defects and lead to research on similar genes that determine the human body plan.
Vera Rubin (shown), Kent Ford and Norbert Thonnard measure the rotation rates of stars in outer parts of galaxies, strongly implying the existence of dark matter.
Astronomers detect the first gravitational lens, seeing a single quasar appear as a double image.
Luis Alvarez and Walter Alvarez publish a report saying that a large space rock hitting Earth was responsible for the mass extinction event 66 million years ago that killed off all nonbird dinosaurs. The father-son team proposed the idea at American Geophysical Union’s annual meeting the year before.
In a big switch, the American Psychiatric Association issues a diagnostic manual that mostly drops psychoanalytic terms and uses sets of symptoms to define mental disorders.
Neurologist Stanley Prusiner identified a misfolded protein, calling it a “prion,” as the infectious agent in the degenerative brain disorder Creutzfeldt-Jakob disease.
In Kenya, Kamoya Kimeu (shown in 1977) discovers a 40 percent complete skeleton of a Homo erectus youngster nicknamed Turkana Boy. Studies of the fossil suggest that humanlike stature may have evolved by 1.6 million years ago.
George Glenner and Caine Wong discovered a “novel cerebrovascular amyloid protein.” That was amyloid-beta, the key component of plaques in the brains of people with Alzheimer’s disease.
Walter Jakob Gehring identifies the homeobox, a cluster of genes expressed in early embryonic development that determine how an organism’s body develops.
Svante Pääbo reports isolating a snippet of DNA from a roughly 2,400-year-old Egyptian mummy. Although the sample may have been contaminated with modern DNA, the investigation kicks off the study of ancient DNA in paleoanthropology.
The space shuttle Challenger explodes, killing all seven crew members, including a high school teacher.
The first baby is born from frozen eggs in Australia.
Scientists trace the wiring diagram of the nervous system of a C. elegans worm.
Margaret Geller, John Huchra and Valérie de Lapparent map a section of the observable universe, revealing a structure that encompasses large walls and giant voids.
An accident at the Chernobyl nuclear power plant in Ukraine killed or sickened dozens of workers and released radioactive material into the environment, requiring the evacuation and resettlement of hundreds of thousands of residents.
A controversial study of modern-day people’s mitochondrial DNA, a type of DNA passed down from mother to child, suggests that all humans can trace their maternal ancestry back to a population that lived in Africa roughly 200,000 years ago.
Geochemist Wallace Broecker describes a global system of ocean currents that transports heat and salt between surface and deep waters and around the globe, influencing regional climates.
The drug fluoxetine, or Prozac, received approval from the U.S. Food and Drug Administration as a treatment for major depression.
Intelligence researcher James Flynn reports large jumps in IQ scores from one generation to the next in many Western nations, indicating that environment shapes performance on intelligence tests.
Alan Handyside of London’s Hammersmith Hospital is able to check an embryo for genetic defects before implanting it into a mother’s uterus. This testing, known as preimplantation genetic diagnosis or PGD, enables parents carrying a genetic or chromosomal defect to avoid passing it to their children.
Seiji Ogawa and colleagues at Bell Labs invent functional magnetic resonance imaging, or fMRI, a method that reveals blood flow changes in the brain, a proxy for activity.
NASA launches the Hubble Space Telescope (shown), one of the sharpest eyes to ever peer into the cosmos.
Based on just nine minutes of data, the Cosmic Background Explorer, or COBE, reveals that the cosmic microwave background radiation aligns with what is expected from blackbody radiation, good evidence that it is an afterglow of the Big Bang.
A powerful eruption from the Philippines’ Mount Pinatubo (shown) ejects millions of tons of sulfur dioxide into the stratosphere, temporarily cooling the planet.
Aleksander Wolszczan and Dale Frail report finding two planets orbiting the pulsar PSR 1257+12 (artist’s conception shown), the first planets discovered outside our solar system.
David Jewitt and Jane Luu spot a population of small objects orbiting the sun beyond Neptune, which came to be known as the Kuiper Belt.
Neuroscientists discover that a protein can prompt mature nerve cells in adult mice to divide, dispelling the belief that adult mammals’ brain cells cannot reproduce. Whether this happens in human brains is still unclear.
Giacomo Rizzolatti and colleagues discovered a set of neurons in the brains of macaque monkeys that fire both when monkeys do something and see another monkey doing it. These neurons would later be called mirror neurons.
Cosmologists detect temperature fluctuations in the cosmic microwave background, variations that correspond to ripples in the density of matter shortly after the Big Bang, as expected from inflation.
Scientists for the first time clone human embryos, raising a host of ethical questions.
Astronomers report evidence of Massive Compact Halo Objects at the outskirts of the Milky Way. These MACHOs account for some but not all of galactic dark matter.
Michel Mayor and Didier Queloz find a giant planet orbiting the star 51 Pegasi, the first exoplanet discovered around a star like the sun.
An academic battle breaks out among evolutionary psychologists and others over the nature of human decision making and what it means to be rational.
Astronomers report the most compelling evidence for the existence of a black hole, at the center of galaxy M87, about 50 million light-years from Earth.
The Intergovernmental Panel on Climate Change establishes that there is evidence of a “discernible” human influence on climate.
Dolly the Sheep (shown) is the first mammal cloned from the DNA of an adult mammal. Ian Wilmut and Keith Campbell of the Roslin Institute transferred the nucleus of an adult mammary gland cell into an egg cell, showing that adult DNA can be reprogrammed to grow a new organism.
Biologists isolate human embryonic stem cells, which have the potential to become nerves, blood or any other tissue.
Astronomers uncover data indicating that the expansion of the universe is picking up speed.
Physicists discover that neutrinos, long thought to be massless, have a tiny amount of mass. The find raises a slew of still-unanswered questions, whether neutrinos are their own antiparticles, for example, or whether the particles can help explain the scarcity of antimatter in the universe.
Australian researcher Alan Trounson reports successful vitrification, a method that freezes eggs so rapidly that no crystals can form. The technique boosts the success rate for using frozen eggs in assisted reproduction.
Two independent research groups report deciphering the genetic blueprint of humans.
A nearly complete skull found in Chad and dating to between 7 million and 6 million years ago may be from the earliest known hominin, Michel Brunet and colleagues announce. The team names the find Sahelanthropus tchadensis.
Astronomers put the age range of the universe at between 13 billion and 14 billion years.
Neurologist Helen Mayberg begins work testing deep brain stimulation on people with severe depression, targeting an area called the subcallosal cingulate.
A surprising find is reported from the Indonesian island of Flores: A small-brained, short-statured hominin lived there about 100,000 to 50,000 years ago. Named Homo floresiensis, but often called the hobbit, the species may be a case of island dwarfism.
A magnitude 9.1 earthquake off the coast of Indonesia spawned a devastating tsunami that killed over 250,000 people in 14 countries.
An implanted grid of electrodes called BrainGate allows a paralyzed man to check his e-mail and play games with his brain activity alone.
A technique to control genetically engineered nerve cells (shown) in animal brains precisely using laser light, now known as optogenetics, is reported.
Physicists at Brookhaven National Laboratory smash nuclei of gold atoms together to recreate the phase of matter thought to have existed in the early moments of the universe. The quark-gluon plasma is a hot, dense soup of quarks intermingling freely with gluons, which under normal conditions bind quarks into larger particles like protons and neutrons.
With all the new bodies discovered in the Kuiper Belt, the International Astronomical Union controversially declares Pluto a dwarf planet, not a planet.
By studying an intergalactic collision (which formed the Bullet Cluster, shown), researchers report compelling evidence of dark matter’s presence in space.
Biologists turn human skin cells into stem cells, without embryos.
A Mars lander definitively confirms the presence of water on Mars, after the rover “touched and tasted ice.”
The Kepler space telescope (illustrated) found thousands of planets outside our solar system before it stopped operating in 2018.
Researchers get a surprise when mitochondrial DNA extracted from a stray finger bone from Russia’s Denisova Cave matches neither Neandertal nor modern human DNA, suggesting a previously unknown hominin lived there.
The Neandertal is the first ancient hominin to have its genetic blueprint, or genome, pieced together. Studies of the ancient DNA reveal humans mated with Neandertals.
Cross-cultural researchers led by anthropologist Joseph Henrich review evidence that members of Western, educated, industrialized, rich and democratic (WEIRD) societies are among the least useful populations to study in order to generalize about how resources get shared and other features of human nature.
A magnitude 9.0 earthquake in Japan and the tsunami it spawned kill more than 15,000 people and damaged reactors at the Fukushima power plant, triggering the worst nuclear disaster since Chernobyl in 1986.
North Carolina sediment cores reveal that sea levels began rising precipitously in the late 19th century, a trend attributed to climate change.
After an earthquake and tsunami, reactors at the Fukushima Daiichi Nuclear Power Station lost power and cooling, resulting in partial meltdowns, explosions and releases of radioactive material. Over 100,000 people were evacuated as a result.
Research groups led by Susumu Tonegawa and Mark Mayford independently create false memories in the brains of mice.
Long-standing inabilities to confirm influential psychology findings in repeat studies spark an ongoing debate over research methods and practices.
A paralyzed woman controls a robotic arm with her mind, enabling her to drink coffee from a bottle.
Physicists at CERN near Geneva report discovery of the final particle predicted by the standard model, the Higgs boson. Its existence confirms scientists’ beliefs about how fundamental particles obtain mass.
Archaeologist Sonia Harmand (shown) and colleagues report that flakes, cores and pounding platforms discovered in Kenya are the oldest known stone tools yet found. They are 3.3 million years old, predating the genus Homo by at least half a million years.
Precise analyses of ancient Siberian lava provide the smoking gun, convicting ancient volcanic eruptions in the greatest known mass extinction on Earth 252 million years ago.
The first baby with three biological parents is born with DNA from his mother, father and the mitochondria of an egg donor. The birth raises hopes for preventing inheritance of mitochondrial disorders —and triggers fears of “designer babies.”
Scientists for the first time report the detection of cosmic ripples in spacetime, gravitational waves from colliding black holes, thus verifying one of general relativity’s predictions.
Jean-Jacques Hublin and colleagues announce that excavations in Morocco have uncovered Homo sapiens fossils dating to about 300,000 years ago. The discoverers say the remains are the oldest known members of our species.
Chinese scientist Jiankui He uses CRISPR/Cas9 to create the first gene-edited babies — twin girls — to reduce their risk of contracting HIV. His actions lead to the formation of an international commission on the clinical use of gene editing.
Researchers with the Event Horizon Telescope report the first image of a black hole, capturing the shadow of M87’s monster on its accretion disk.
SpaceX launches three astronauts to the International Space Station, marking the first time a private company sent humans into orbit.
A National Academies of Sciences, Engineering and Medicine report documents rising numbers of premature deaths in the United States since the 1990s from drug overdoses, alcohol abuse, suicides and obesity. COVID-19 exacerbated that trend, the report concludes.