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For a topic outline of science, see Outline of science.

French Academy of Sciences

Members of the Academy in 1667 with Louis XIV

Science (from Latin scientia 'knowledge') is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the world.

The earliest roots of science can be traced to Ancient Egypt and Mesopotamia in around 3000 to 1200 BCE. Their contributions to mathematics, astronomy, and medicine entered and shaped Greek natural philosophy of classical antiquity, whereby formal attempts were made to provide explanations of events in the physical world based on natural causes. After the fall of the Western Roman Empire, knowledge of Greek conceptions of the world deteriorated in Western Europe during the early centuries (400 to 1000 CE) of the Middle Ages, but was preserved in the Muslim world during the Islamic Golden Age. The recovery and assimilation of Greek works and Islamic inquiries into Western Europe from the 10th to 13th century revived "natural philosophy", which was later transformed by the Scientific Revolution that began in the 16th century as new ideas and discoveries departed from previous Greek conceptions and traditions. The scientific method soon played a greater role in knowledge creation and it was not until the 19th century that many of the institutional and professional features of science began to take shape; along with the changing of "natural philosophy" to "natural science."

Modern science is typically divided into three major branches that consist of the natural sciences (e.g., biology, chemistry, and physics), which study nature in the broadest sense; the social sciences (e.g., economics, psychology, and sociology), which study individuals and societies; and the formal sciences (e.g., logic, mathematics, and theoretical computer science), which deal with symbols governed by rules. There is disagreement, however, on whether the formal sciences actually constitute a science as they do not rely on empirical evidence. Disciplines that use existing scientific knowledge for practical purposes, such as engineering and medicine, are described as applied sciences.

New knowledge in science is advanced by research from scientists who are motivated by curiosity about the world and a desire to solve problems. Contemporary scientific research is highly collaborative and is usually done by teams in academic and research institutions, government agencies, and companies. The practical impact of their work has led to the emergence of science policies that seek to influence the scientific enterprise by prioritizing the development of commercial products, armaments, health care, public infrastructure, and environmental protection. (Full article...)

Featured article

  Featured articles are displayed here, which represent some of the best content on English Wikipedia.

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  Radiocarbon dating (also referred to as carbon dating or carbon-14 dating) is a method for determining the age of an object containing organic material by using the properties of radiocarbon, a radioactive isotope of carbon.
  
  The method was developed in the late 1940s at the University of Chicago by Willard Libby. It is based on the fact that radiocarbon (¹⁴
  C) is constantly being created in the Earth's atmosphere by the interaction of cosmic rays with atmospheric nitrogen. The resulting ¹⁴
  C combines with atmospheric oxygen to form radioactive carbon dioxide, which is incorporated into plants by photosynthesis; animals then acquire ¹⁴
  C by eating the plants. When the animal or plant dies, it stops exchanging carbon with its environment, and thereafter the amount of ¹⁴
  C it contains begins to decrease as the ¹⁴
  C undergoes radioactive decay. Measuring the amount of ¹⁴
  C in a sample from a dead plant or animal, such as a piece of wood or a fragment of bone, provides information that can be used to calculate when the animal or plant died. The older a sample is, the less ¹⁴
  C there is to be detected, and because the half-life of ¹⁴
  C (the period of time after which half of a given sample will have decayed) is about 5,730 years, the oldest dates that can be reliably measured by this process date to approximately 50,000 years ago, although special preparation methods occasionally make accurate analysis of older samples possible. Libby received the Nobel Prize in Chemistry for his work in 1960. (Full article...)
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  Fire ants

  
  Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants appear in the fossil record across the globe in considerable diversity during the latest Early Cretaceous and early Late Cretaceous, suggesting an earlier origin. Ants evolved from vespoid wasp ancestors in the Cretaceous period, and diversified after the rise of flowering plants. More than 13,800 of an estimated total of 22,000 species have been classified. They are easily identified by their geniculate (elbowed) antennae and the distinctive node-like structure that forms their slender waists.
  
  Ants form colonies that range in size from a few dozen predatory individuals living in small natural cavities to highly organised colonies that may occupy large territories and consist of millions of individuals. Larger colonies consist of various castes of sterile, wingless females, most of which are workers (ergates), as well as soldiers (dinergates) and other specialised groups. Nearly all ant colonies also have some fertile males called "drones" and one or more fertile females called "queens" (gynes). The colonies are described as superorganisms because the ants appear to operate as a unified entity, collectively working together to support the colony. (Full article...)
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  The Wells and Wellington affair was a dispute about the publication of three papers in the Australian Journal of Herpetology in 1983 and 1985. The periodical was established in 1981 as a peer-reviewed scientific journal focusing on the study of amphibians and reptiles (herpetology). Its first two issues were published under the editorship of Richard W. Wells, a first-year biology student at Australia's University of New England. Wells then ceased communicating with the journal's editorial board for two years before suddenly publishing three papers without peer review in the journal in 1983 and 1985. Coauthored by himself and high school teacher Cliff Ross Wellington, the papers reorganized the taxonomy of all of Australia's and New Zealand's amphibians and reptiles and proposed over 700 changes to the binomial nomenclature of the region's herpetofauna.
  
  Members of the herpetological community reacted strongly to the pair's actions and eventually brought a case to the International Commission on Zoological Nomenclature to suppress the scientific names they had proposed. After four years of arguments, the commission opted not to vote on the case because it hinged largely on taxonomic arguments rather than nomenclatural ones, leaving some of Wells and Wellington's names available. The case's outcome highlighted the vulnerability to the established rules of biological nomenclature that desktop publishing presented. As of 2020, 24 of the specific names assigned by Wells and Wellington remained valid senior synonyms. (Full article...)
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  Phoenix is a minor constellation in the southern sky. Named after the mythical phoenix, it was first depicted on a celestial atlas by Johann Bayer in his 1603 Uranometria. The French explorer and astronomer Nicolas Louis de Lacaille charted the brighter stars and gave their Bayer designations in 1756. The constellation stretches from roughly −39° to −57° declination, and from 23.5h to 2.5h of right ascension. The constellations Phoenix, Grus, Pavo and Tucana, are known as the Southern Birds.
  
  The brightest star, Alpha Phoenicis, is named Ankaa, an Arabic word meaning 'the Phoenix'. It is an orange giant of apparent magnitude 2.4. Next is Beta Phoenicis, actually a binary system composed of two yellow giants with a combined apparent magnitude of 3.3. Nu Phoenicis has a dust disk, while the constellation has ten star systems with known planets and the recently discovered galaxy clusters El Gordo and the Phoenix Cluster—located 7.2 and 5.7 billion light years away respectively, two of the largest objects in the visible universe. Phoenix is the radiant of two annual meteor showers: the Phoenicids in December, and the July Phoenicids. (Full article...)
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  Telopea truncata, commonly known as the Tasmanian waratah, is a plant in the family Proteaceae. It is endemic to Tasmania where it is found on moist acidic soils at altitudes of 600 to 1200 m (2000–4000 ft). Telopea truncata is a component of alpine eucalypt forest, rainforest and scrub communities. It grows as a multistemmed shrub to a height of 3 metres (10 ft), or occasionally as a small tree to 10 m (35 ft) high, with red flower heads, known as inflorescences, appearing over the Tasmanian summer (November to February) and bearing 10 to 35 individual flowers. Yellow-flowered forms are occasionally seen, but do not form a population distinct from the rest of the species.
  
  Collected by French botanist Jacques Labillardière in 1792–93, Telopea truncata was first scientifically described in 1805. Genetic analysis revealed that the Tasmanian waratah is the most distinctive of the five waratah species. It can be cultivated in temperate climates, requiring soils with good drainage and ample moisture in part-shaded or sunny positions. Several commercially available cultivars that are hybrids of T. truncata with the New South Wales waratah (T. speciosissima) and Gippsland waratah (T. oreades) have been developed. (Full article...)
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  Extrusion billets of aluminium

  
  Aluminium (or aluminum) metal is very rare in native form, and the process to refine it from ores is complex, so for most of human history it was unknown. However, the compound alum has been known since the 5th century BCE and was used extensively by the ancients for dyeing. During the Middle Ages, its use for dyeing made it a commodity of international commerce. Renaissance scientists believed that alum was a salt of a new earth; during the Age of Enlightenment, it was established that this earth, alumina, was an oxide of a new metal. Discovery of this metal was announced in 1825 by Danish physicist Hans Christian Ørsted, whose work was extended by German chemist Friedrich Wöhler.
  
  Aluminium was difficult to refine and thus uncommon in actual usage. Soon after its discovery, the price of aluminium exceeded that of gold. It was only reduced after the initiation of the first industrial production by French chemist Henri Étienne Sainte-Claire Deville in 1856. In 1878, James Fern Webster was producing 100lbs of pure Aluminium every week at his Solihull Lodge factory in Warwickshire. He used a chemical process. In 1884, he established a trading title, Webster's Patent Aluminium Crown Metal Company Ltd. Aluminium became much more available to the public with the Hall–Héroult process developed independently by French engineer Paul Héroult and American engineer Charles Martin Hall in 1886, and the Bayer process developed by Austrian chemist Carl Joseph Bayer in 1889. These processes have been used for aluminium production up to the present. (Full article...)
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  The common starling or European starling (Sturnus vulgaris), also known simply as the starling in Great Britain and Ireland, is a medium-sized passerine bird in the starling family, Sturnidae. It is about 20 cm (8 in) long and has glossy black plumage with a metallic sheen, which is speckled with white at some times of year. The legs are pink and the bill is black in winter and yellow in summer; young birds have browner plumage than the adults. It is a noisy bird, especially in communal roosts and other gregarious situations, with an unmusical but varied song. Its gift for mimicry has been noted in literature including the Mabinogion and the works of Pliny the Elder and William Shakespeare.
  
  The common starling has about 12 subspecies breeding in open habitats across its native range in temperate Europe and across the Palearctic to western Mongolia, and it has been introduced to Australia, New Zealand, Canada, the United States, Mexico, Argentina, South Africa and Fiji. This bird is resident in western and southern Europe and southwestern Asia, while northeastern populations migrate south and west in the winter within the breeding range and also further south to Iberia and North Africa. The common starling builds an untidy nest in a natural or artificial cavity in which four or five glossy, pale blue eggs are laid. These take two weeks to hatch and the young remain in the nest for another three weeks. There are normally one or two breeding attempts each year. This species is omnivorous, taking a wide range of invertebrates, as well as seeds and fruit. It is hunted by various mammals and birds of prey, and is host to a range of external and internal parasites. (Full article...)
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  Lilias Eveline Armstrong (29 September 1882 – 9 December 1937) was an English phonetician. She worked at University College London, where she attained the rank of reader. Armstrong is most known for her work on English intonation as well as the phonetics and tone of Somali and Kikuyu. Her book on English intonation, written with Ida C. Ward, was in print for 50 years. Armstrong also provided some of the first detailed descriptions of tone in Somali and Kikuyu.
  
  Armstrong grew up in Northern England. She graduated from the University of Leeds, where she studied French and Latin. She taught French in an elementary school in the London suburbs for a while, but then joined the University College Phonetics Department, headed by Daniel Jones. Her most notable works were the 1926 book A Handbook of English Intonation, co-written with Ward, the 1934 paper "The Phonetic Structure of Somali", and the book The Phonetic and Tonal Structure of Kikuyu, published posthumously in 1940 after she died of a stroke in 1937 at age 55. (Full article...)
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  Yellowstone National Park is an American national park located in the western United States, largely in the northwest corner of Wyoming and extending into Montana and Idaho. It was established by the U.S. Congress and signed into law by President Ulysses S. Grant on March 1, 1872. Yellowstone was the first national park in the U.S. and is also widely held to be the first national park in the world. The park is known for its wildlife and its many geothermal features, especially Old Faithful geyser, one of its most popular. While it represents many types of biomes, the subalpine forest is the most abundant. It is part of the South Central Rockies forests ecoregion.
  
  While Native Americans have lived in the Yellowstone region for at least 11,000 years, aside from visits by mountain men during the early-to-mid-19th century, organized exploration did not begin until the late 1860s. Management and control of the park originally fell under the jurisdiction of the United States Department of the Interior, the first Secretary of the Interior to supervise the park being Columbus Delano. However, the U.S. Army was eventually commissioned to oversee management of Yellowstone for a 30-year period between 1886 and 1916. In 1917, administration of the park was transferred to the National Park Service, which had been created the previous year. Hundreds of structures have been built and are protected for their architectural and historical significance, and researchers have examined more than a thousand archaeological sites. (Full article...)
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  First edition cover

  
  The Story of Miss Moppet is a tale about teasing, featuring a kitten and a mouse, that was written and illustrated by Beatrix Potter, and published by Frederick Warne & Co for the 1906 Christmas season. Potter was born in London in 1866, and between 1902 and 1905 published a series of small-format children's books with Warne. In 1906, she experimented with an atypical panorama design for Miss Moppet, which booksellers disliked; the story was reprinted in 1916 in small book format.
  
  Miss Moppet, the story's eponymous main character, is a kitten teased by a mouse. While pursuing him she bumps her head on a cupboard. She then wraps a duster about her head, and sits before the fire "looking very ill". The curious mouse creeps closer, is captured, "and because the Mouse has teased Miss Moppet—Miss Moppet thinks she will tease the Mouse; which is not at all nice of Miss Moppet". She ties him up in the duster and tosses him about. However, the mouse makes his escape, and once safely out of reach, dances a jig atop the cupboard. (Full article...)
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  Title page from the second volume of Lives of the Most Eminent Literary and Scientific Men of France (1838)

  
  
  The Lives of the Most Eminent Literary and Scientific Men comprised ten volumes of Dionysius Lardner's 133-volume Cabinet Cyclopaedia (1829–1846). Aimed at the self-educating middle class, this encyclopedia was written during the 19th-century literary revolution in Britain that encouraged more people to read.
  
  The Lives formed part of the Cabinet of Biography in the Cabinet Cyclopaedia. Within the set of ten, the three-volume Lives of the Most Eminent Literary and Scientific Men of Italy, Spain and Portugal (1835–37) and the two-volume Lives of the Most Eminent Literary and Scientific Men of France (1838–39) consist of biographies of important writers and thinkers of the 14th to 18th centuries. Most of them were written by the Romantic writer Mary Shelley. Shelley's biographies reveal her as a professional woman of letters, contracted to produce several volumes of works and paid well to do so. Her extensive knowledge of history and languages, her ability to tell a gripping biographical narrative, and her interest in the burgeoning field of feminist historiography are reflected in these works. (Full article...)
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  The Oort cloud (/ɔːrt, ʊərt/), sometimes called the Öpik–Oort cloud, first described in 1950 by the Dutch astronomer Jan Oort, is a theoretical concept of a cloud of predominantly icy planetesimals proposed to surround the Sun at distances ranging from 2,000 to 200,000 au (0.03 to 3.2 light-years). It is divided into two regions: a disc-shaped inner Oort cloud (or Hills cloud) and a spherical outer Oort cloud. Both regions lie beyond the heliosphere and in interstellar space. The Kuiper belt and the scattered disc, the other two reservoirs of trans-Neptunian objects, are less than one thousandth as far from the Sun as the Oort cloud.
  
  The outer limit of the Oort cloud defines the cosmographic boundary of the Solar System and the extent of the Sun's Hill sphere. The outer Oort cloud is only loosely bound to the Solar System, and thus is easily affected by the gravitational pull both of passing stars and of the Milky Way itself. These forces occasionally dislodge comets from their orbits within the cloud and send them toward the inner Solar System. Based on their orbits, most of the short-period comets may come from the scattered disc, but some short-period comets may have originated from the Oort cloud. (Full article...)
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  Black currawong, Tasmania

  
  The black currawong (Strepera fuliginosa), also known locally as the black jay, is a large passerine bird endemic to Tasmania and the nearby islands within the Bass Strait. One of three currawong species in the genus Strepera, it is closely related to the butcherbirds and Australian magpie within the family Artamidae. It is a large crow-like bird, around 50 cm (20 in) long on average, with yellow irises, a heavy bill, and black plumage with white wing patches. The male and female are similar in appearance. Three subspecies are recognised, one of which, Strepera fuliginosa colei of King Island, is vulnerable to extinction.
  
  Within its range, the black currawong is generally sedentary, although populations at higher altitudes relocate to lower areas during the cooler months. The habitat includes densely forested areas as well as alpine heathland. It is rare below altitudes of 200 m (660 ft). Omnivorous, its diet includes a variety of berries, invertebrates, and small vertebrates. Less arboreal than the pied currawong, the black currawong spends more time foraging on the ground. It roosts and breeds in trees. (Full article...)
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  Mounted cast of a fossil E. annectens skeleton, Rocky Mountain Dinosaur Resource Center

  
  Edmontosaurus (/ɛdˌmɒntəˈsɔːrəs/ ed-MON-tə-SAWR-əs) (meaning "lizard from Edmonton") is a genus of hadrosaurid (duck-billed) dinosaur. It contains two known species: Edmontosaurus regalis and Edmontosaurus annectens. Fossils of E. regalis have been found in rocks of western North America that date from the late Campanian stage of the Cretaceous Period 73 million years ago, while those of E. annectens were found in the same geographic region but in rocks dated to the end of the Maastrichtian stage of the Cretaceous, 66 million years ago. Edmontosaurus was one of the last non-avian dinosaurs, and lived alongside dinosaurs like Triceratops, Tyrannosaurus, and Pachycephalosaurus shortly before the Cretaceous–Paleogene extinction event.
  
  Edmontosaurus included some of the largest hadrosaurid species, measuring up to 12 metres (39 ft) long and weighing around 4.0 metric tons (4.4 short tons). Evidence does exist in the form of two fossilized specimens housed at the Museum of the Rockies for an even greater maximum size of 15 m (49 ft) and weighing 9.07 metric tons (10.00 short tons) for Edmontosaurus annectens. Several well-preserved specimens are known that include not only bones, but in some cases extensive skin impressions and possible gut contents. It is classified as a genus of saurolophine (or hadrosaurine) hadrosaurid, a member of the group of hadrosaurids which lacked large, hollow crests, instead having smaller solid crests or fleshy combs. (Full article...)
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  Adult of subspecies P. m. saturatus in Japan

  
  The Eurasian tree sparrow (Passer montanus) is a passerine bird in the sparrow family with a rich chestnut crown and nape, and a black patch on each pure white cheek. The sexes are similarly plumaged, and young birds are a duller version of the adult. This sparrow breeds over most of temperate Eurasia and Southeast Asia, where it is known as the tree sparrow, and it has been introduced elsewhere including the United States, where it is known as the Eurasian tree sparrow or German sparrow to differentiate it from the native unrelated American tree sparrow. Although several subspecies are recognised, the appearance of this bird varies little across its extensive range.
  
  The Eurasian tree sparrow's untidy nest is built in a natural cavity, a hole in a building or the disused nest of a European magpie or white stork. The typical clutch is five or six eggs which hatch in under two weeks. This sparrow feeds mainly on seeds, but invertebrates are also consumed, particularly during the breeding season. As with other small birds, infection by parasites and diseases, and predation by birds of prey take their toll, and the typical life span is about two years. (Full article...)

Selected image

Earth

Credit: Earth Sciences and Image Analysis Laboratory, NASA

View of the Earth as seen by the Apollo 17 crew traveling toward the moon. This translunar coast photograph extends from the Mediterranean Sea area to the Antarctica south polar ice cap. This is toward the northeast. Earth, also known as Terra, and (mostly in the 19th century) Tellus, is the third-closest planet to the Sun. It is the largest of the solar system's terrestrial planets and the only planetary body that modern science confirms as harboring life. Scientific evidence indicates that the planet formed around 4.57 billion years ago, and shortly thereafter (4.533 billion years ago) acquired its single natural satellite, the Moon.

Selected biography

Barry Voight (/vɔɪt/; born 1937) is an American geologist, volcanologist, author, and engineer. After earning his Ph.D. at Columbia University, Voight worked as a professor of geology at several universities, including Pennsylvania State University, where he taught from 1964 until his retirement in 2005. He remains an emeritus professor there and still conducts research, focusing on rock mechanics, plate tectonics, disaster prevention, and geotechnical engineering.

In April 1980, Voight's publications on landslides, avalanches, and other mass movements attracted the attention of Rocky Crandell of the United States Geological Survey (USGS), who asked him to look at a growing bulge on the Mount St. Helens volcano in the state of Washington. Voight foresaw the collapse of the mountain's north flank as well as a powerful eruption. His predictions came true when St. Helens erupted in May 1980; Voight was then hired by the USGS to investigate the debris avalanche that initiated the eruption. After his work at Mount St. Helens brought him international recognition, Voight continued researching and guiding monitoring efforts at several active volcanoes throughout his career, including Nevado del Ruiz in Colombia, Mount Merapi in Indonesia, and Soufrière Hills, a volcano on the Caribbean island of Montserrat. For his research, publications, and disaster prevention work as a volcanologist and engineer, Voight has been honored with numerous awards, appointments, and medals.

Did you know...

• ...that space artist Jon Lomberg (artwork pictured) was Carl Sagan's principal artistic collaborator on many projects such as Cosmos and the Voyager Golden Record?
• ...that NASA astronaut Stephen Robinson has logged 497 hours in space?
• ...that Othniel Charles Marsh named two species of the dinosaur Coelurus from the same quarry, not knowing that the bones belonged to the same skeleton?
• ...that the type specimen of Dromicosuchus had damage to its jaw and neck that may have been inflicted by the teeth of the large carnivore it was found underneath?
• ...that the scientific name of the common Australian garden fungus Aseroë rubra means 'red disgusting juice'?

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