In political science, a revolution is a fundamental and sudden change in political power and political organization which occurs when the population revolts against the government due to perceived oppression or political incompetence. In book V of the Politics, the Ancient Greek philosopher Aristotle described two types of political revolution: Complete change from one constitution to another Modification of an existing constitution. Revolutions have occurred through human history and vary in terms of methods and motivating ideology, their results include major changes in culture and socio-political institutions in response to perceived overwhelming autocracy or plutocracy. Scholarly debates about what does not constitute a revolution center on several issues. Early studies of revolutions analyzed events in European history from a psychological perspective, but more modern examinations include global events and incorporate perspectives from several social sciences, including sociology and political science.
Several generations of scholarly thought on revolutions have generated many competing theories and contributed much to the current understanding of this complex phenomenon. Notable revolutions during centuries include the creation of the United States through the American Revolutionary War, the French Revolution, the 1848 European Revolutions, the Russian Revolution in 1917, the Chinese Revolution of the 1940s, the Cuban Revolution in 1959; the word "revolucion" is known in French from the 13th century, "revolution" in English by the late fourteenth century, with regard to the revolving motion of celestial bodies. "Revolution" in the sense of representing abrupt change in a social order is attested by at least 1450. Political usage of the term had been well established by 1688 in the description of the replacement of James II with William III; this incident was termed the "Glorious Revolution". There are many different typologies of revolutions in social literature. Alexis de Tocqueville differentiated between.
One of several different Marxist typologies divides revolutions into. Mark Katz identified six forms of revolution. Revolution by osmosis, e.g. the gradual Islamization of several countries. These categories are not mutually exclusive. Katz cross-classified revolutions as follows. Aspiring revolutions, which follow the Central revolution subordinate or puppet revolutions rival revolutions, e.g. communist Yugoslavia, China after 1969A further dimension to Katz's typology is that revolutions are either against or for. In the latter cases, a transition period is necessary to decide on the direction taken. Other types of revolution, created for other typologies, include the social revolutions; the term revolution has been used to denote great changes outside the political sphere. Such revolutions are recognized as having transformed in society, culture and technology much more than political systems; some can be global. One of the classic examples of the usage of the word revolution in such context is the Industrial Revolution, or the Commercial Revolution.
Note that such revolutions fit the "slow revolution" definition of Tocqueville. A similar example is the Digital Revolution. Most the word "revolution" is employed to denote a change in social and political institutions. Jeff Goodwin gives two definitions of a revolution. First, a broad one, including any and all instances in which a state or a political regime is overthrown and thereby transformed by a popular movement in an irregular, extraconstitutional and/or violent fashion. Second, a narrow one, in which revolutions entail not only mass mobilization and regime change, but more or less rapid and fundamental social, economic and/or cultural change, during or soon after the struggle for state power. Jack Goldstone defines a revolution as an effort to transform the political institutions and the justifications for political authority in society, accompanied by formal or informal mass
OCLC Online Computer Library Center, Incorporated d/b/a OCLC is an American nonprofit cooperative organization "dedicated to the public purposes of furthering access to the world's information and reducing information costs". It was founded in 1967 as the Ohio College Library Center. OCLC and its member libraries cooperatively produce and maintain WorldCat, the largest online public access catalog in the world. OCLC is funded by the fees that libraries have to pay for its services. OCLC maintains the Dewey Decimal Classification system. OCLC began in 1967, as the Ohio College Library Center, through a collaboration of university presidents, vice presidents, library directors who wanted to create a cooperative computerized network for libraries in the state of Ohio; the group first met on July 5, 1967 on the campus of the Ohio State University to sign the articles of incorporation for the nonprofit organization, hired Frederick G. Kilgour, a former Yale University medical school librarian, to design the shared cataloging system.
Kilgour wished to merge the latest information storage and retrieval system of the time, the computer, with the oldest, the library. The plan was to merge the catalogs of Ohio libraries electronically through a computer network and database to streamline operations, control costs, increase efficiency in library management, bringing libraries together to cooperatively keep track of the world's information in order to best serve researchers and scholars; the first library to do online cataloging through OCLC was the Alden Library at Ohio University on August 26, 1971. This was the first online cataloging by any library worldwide. Membership in OCLC is based on use of services and contribution of data. Between 1967 and 1977, OCLC membership was limited to institutions in Ohio, but in 1978, a new governance structure was established that allowed institutions from other states to join. In 2002, the governance structure was again modified to accommodate participation from outside the United States.
As OCLC expanded services in the United States outside Ohio, it relied on establishing strategic partnerships with "networks", organizations that provided training and marketing services. By 2008, there were 15 independent United States regional service providers. OCLC networks played a key role in OCLC governance, with networks electing delegates to serve on the OCLC Members Council. During 2008, OCLC commissioned two studies to look at distribution channels. In early 2009, OCLC negotiated new contracts with the former networks and opened a centralized support center. OCLC provides bibliographic and full-text information to anyone. OCLC and its member libraries cooperatively produce and maintain WorldCat—the OCLC Online Union Catalog, the largest online public access catalog in the world. WorldCat has holding records from private libraries worldwide; the Open WorldCat program, launched in late 2003, exposed a subset of WorldCat records to Web users via popular Internet search and bookselling sites.
In October 2005, the OCLC technical staff began a wiki project, WikiD, allowing readers to add commentary and structured-field information associated with any WorldCat record. WikiD was phased out; the Online Computer Library Center acquired the trademark and copyrights associated with the Dewey Decimal Classification System when it bought Forest Press in 1988. A browser for books with their Dewey Decimal Classifications was available until July 2013; until August 2009, when it was sold to Backstage Library Works, OCLC owned a preservation microfilm and digitization operation called the OCLC Preservation Service Center, with its principal office in Bethlehem, Pennsylvania. The reference management service QuestionPoint provides libraries with tools to communicate with users; this around-the-clock reference service is provided by a cooperative of participating global libraries. Starting in 1971, OCLC produced catalog cards for members alongside its shared online catalog. OCLC commercially sells software, such as CONTENTdm for managing digital collections.
It offers the bibliographic discovery system WorldCat Discovery, which allows for library patrons to use a single search interface to access an institution's catalog, database subscriptions and more. OCLC has been conducting research for the library community for more than 30 years. In accordance with its mission, OCLC makes its research outcomes known through various publications; these publications, including journal articles, reports and presentations, are available through the organization's website. OCLC Publications – Research articles from various journals including Code4Lib Journal, OCLC Research, Reference & User Services Quarterly, College & Research Libraries News, Art Libraries Journal, National Education Association Newsletter; the most recent publications are displayed first, all archived resources, starting in 1970, are available. Membership Reports – A number of significant reports on topics ranging from virtual reference in libraries to perceptions about library funding. Newsletters – Current and archived newsletters for the library and archive community.
Presentations – Presentations from both guest speakers and OCLC research from conferences and other events. The presentations are organized into five categories: Conference presentations, Dewey presentations, Distinguished Seminar Series, Guest presentations, Research staff
Ice is water frozen into a solid state. Depending on the presence of impurities such as particles of soil or bubbles of air, it can appear transparent or a more or less opaque bluish-white color. In the Solar System, ice is abundant and occurs from as close to the Sun as Mercury to as far away as the Oort cloud objects. Beyond the Solar System, it occurs as interstellar ice, it is abundant on Earth's surface – in the polar regions and above the snow line – and, as a common form of precipitation and deposition, plays a key role in Earth's water cycle and climate. It occurs as frost, icicles or ice spikes. Ice molecules can exhibit more different phases that depend on temperature and pressure; when water is cooled up to three different types of amorphous ice can form depending on the history of its pressure and temperature. When cooled correlated proton tunneling occurs below −253.15 °C giving rise to macroscopic quantum phenomena. All the ice on Earth's surface and in its atmosphere is of a hexagonal crystalline structure denoted as ice Ih with minute traces of cubic ice denoted as ice Ic.
The most common phase transition to ice Ih occurs when liquid water is cooled below 0 °C at standard atmospheric pressure. It may be deposited directly by water vapor, as happens in the formation of frost; the transition from ice to water is melting and from ice directly to water vapor is sublimation. Ice is used in a variety including cooling, winter sports and ice sculpture; as a occurring crystalline inorganic solid with an ordered structure, ice is considered to be a mineral. It possesses a regular crystalline structure based on the molecule of water, which consists of a single oxygen atom covalently bonded to two hydrogen atoms, or H–O–H. However, many of the physical properties of water and ice are controlled by the formation of hydrogen bonds between adjacent oxygen and hydrogen atoms. An unusual property of ice frozen at atmospheric pressure is that the solid is 8.3% less dense than liquid water. The density of ice is 0.9167–0.9168 g/cm3 at 0 °C and standard atmospheric pressure, whereas water has a density of 0.9998–0.999863 g/cm3 at the same temperature and pressure.
Liquid water is densest 1.00 g/cm3, at 4 °C and becomes less dense as the water molecules begin to form the hexagonal crystals of ice as the freezing point is reached. This is due to hydrogen bonding dominating the intermolecular forces, which results in a packing of molecules less compact in the solid. Density of ice increases with decreasing temperature and has a value of 0.9340 g/cm3 at −180 °C. When water freezes, it increases in volume; the effect of expansion during freezing can be dramatic, ice expansion is a basic cause of freeze-thaw weathering of rock in nature and damage to building foundations and roadways from frost heaving. It is a common cause of the flooding of houses when water pipes burst due to the pressure of expanding water when it freezes; the result of this process is that ice floats on liquid water, an important feature in Earth's biosphere. It has been argued that without this property, natural bodies of water would freeze, in some cases permanently, from the bottom up, resulting in a loss of bottom-dependent animal and plant life in fresh and sea water.
Sufficiently thin ice sheets allow light to pass through while protecting the underside from short-term weather extremes such as wind chill. This creates a sheltered environment for algal colonies; when sea water freezes, the ice is riddled with brine-filled channels which sustain sympagic organisms such as bacteria, algae and annelids, which in turn provide food for animals such as krill and specialised fish like the bald notothen, fed upon in turn by larger animals such as emperor penguins and minke whales. When ice melts, it absorbs as much energy as it would take to heat an equivalent mass of water by 80 °C. During the melting process, the temperature remains constant at 0 °C. While melting, any energy added breaks the hydrogen bonds between ice molecules. Energy becomes available to increase the thermal energy only after enough hydrogen bonds are broken that the ice can be considered liquid water; the amount of energy consumed in breaking hydrogen bonds in the transition from ice to water is known as the heat of fusion.
As with water, ice absorbs light at the red end of the spectrum preferentially as the result of an overtone of an oxygen–hydrogen bond stretch. Compared with water, this absorption is shifted toward lower energies. Thus, ice appears blue, with a greener tint than liquid water. Since absorption is cumulative, the color effect intensifies with increasing thickness or if internal reflections cause the light to take a longer path through the ice. Other colors can appear in the presence of light absorbing impurities, where the impurity is dictating the color rather than the ice itself. For instance, icebergs containing impurities can appear grey or green. Ice may be any one of the 18 known solid crystalline phases of water, or in an amorphous solid state at various densities. Most liquids under increased pressure freeze at higher temperatures because the pressure helps to hold the molecules together. However, the strong hydrogen bonds in water make it different: For some pressures higher than 1 atm, water freezes at a temperature below
Ursula K. Le Guin
Ursula Kroeber Le Guin was an American author. She was best known for her works of speculative fiction, including the science fiction works set in the Hainish Universe and the fantasy series of Earthsea. First published in 1959, she had a literary career spanning nearly sixty years, during which she released more than twenty novels and over a hundred short stories, in addition to many volumes of poetry, literary criticism and children's books. Described as author of science fiction, Le Guin said she would prefer to be known as an "American novelist", has been called a "major voice in American Letters". Le Guin was born in Berkeley, California, to author Theodora Kroeber and scholar Alfred Louis Kroeber. Having earned a master's degree in French, Le Guin began doctoral studies, but abandoned these after her marriage in 1953 to historian Charles Le Guin, she began writing full-time in the 1950s, achieved major critical and commercial success with A Wizard of Earthsea and The Left Hand of Darkness, described by Harold Bloom as her masterpieces.
For the latter volume Le Guin won both the Hugo and Nebula awards for best novel, becoming the first woman to do so. Several more works set in Earthsea or the Hainish Universe followed. Le Guin was influenced by cultural anthropology, Taoism and the writing of Jungian psychology. Many of her stories used anthropologists or cultural observers as protagonists, Taoist ideas about balance and equilibrium have been identified in several works. Le Guin subverted tropes typical to speculative fiction, such as through her use of dark-skinned protagonists in Earthsea, used unusual stylistic or structural devices in books such as Always Coming Home. Social and political themes, including gender and coming of age were prominent in her writing, she explored alternative political structures in many stories, notably in the parable "The Ones Who Walk Away from Omelas" and the utopian novel The Dispossessed. Le Guin's writing was enormously influential in the field of speculative fiction, was the subject of intense critical attention.
She received numerous accolades, including seven Hugos, six Nebulas, twenty-two Locus Awards, was made a Grand Master of the Science Fiction and Fantasy Writers of America in 2003, only the second woman so honored. The U. S. Library of Congress named her a Living Legend in 2000, in 2014, she won the National Book Foundation Medal for Distinguished Contribution to American Letters. Le Guin influenced many other authors, including Booker Prize winner Salman Rushdie, David Mitchell, Neil Gaiman, Iain Banks. On her death in 2018 critic John Clute wrote that Le Guin had "presided over American science fiction for nearly half a century", while author Michael Chabon referred to her as the "greatest American writer of her generation". Ursula K. Le Guin was born Ursula Kroeber in Berkeley, California, on October 21, 1929, her father Alfred Louis Kroeber was an anthropologist at the University of Berkeley. Le Guin's mother Theodora Kroeber had a graduate degree in psychology, but turned to writing in her sixties.
She developed a successful career as an author: her best known work was Ishi in Two Worlds, a biographical volume about Ishi, an indigenous American, the last known member of the Yahi tribe. Ursula had three older brothers, Karl and Clifton; the family had a large book collection, the siblings all became interested in reading while they were young. The Kroeber family had a number of visitors, who included well-known academics such as Robert Oppenheimer: Le Guin would use Oppenheimer as the model for her protagonist in The Dispossessed; the family divided its time between a summer home in the Napa valley, a house in Berkeley during the academic year. Le Guin's reading included science fiction and fantasy: she and her siblings read issues of Thrilling Wonder Stories and Astounding Science Fiction, she was fond of myths and legends Norse mythology, of Native American legends that her father would narrate. Other authors she enjoyed were Lewis Padgett. Le Guin developed an early interest in writing.
The piece was rejected, she did not submit anything else for another ten years. Le Guin attended Berkeley High School, she received her Bachelor of Arts in Renaissance French and Italian literature from Radcliffe College in 1951, graduated as a member of the Phi Beta Kappa honor society. As a child she had been interested in biology and poetry, but had been limited in her opportunities by her difficulties with mathematics. Le Guin undertook graduate studies at Columbia University, earned a Master of Arts in French in 1952. Soon after, she began working towards a Ph. D. and won a Fulbright grant to continue her studies in France from 1953 to 1954. In 1953, while traveling to France aboard the Queen Mary, Ursula met historian Charles Le Guin, they got married in Paris in December 1953. According to Le Guin, the marriage signaled the "end of the doctorate" for her. While her husband finished his doctorate at Emory University in Georgia, at the University of Idaho, Le Guin taught French and worked as a secretary until the birth of her daughter Elisabeth in 1957.
In 1959 Charles became an instructor in history at Portland State University, the couple moved to Portland, Oregon. They would remain there for the rest of their lives, although Le Guin received further Fulbright grants to
Science fiction is a genre of speculative fiction dealing with imaginative and futuristic concepts such as advanced science and technology, space exploration, time travel, extraterrestrials in fiction. Science fiction explores the potential consequences of scientific other various innovations, has been called a "literature of ideas." "Science fiction" is difficult to define as it includes a wide range of concepts and themes. James Blish wrote: "Wells used the term to cover what we would today call'hard' science fiction, in which a conscientious attempt to be faithful to known facts was the substrate on which the story was to be built, if the story was to contain a miracle, it ought at least not to contain a whole arsenal of them."Isaac Asimov said: "Science fiction can be defined as that branch of literature which deals with the reaction of human beings to changes in science and technology." According to Robert A. Heinlein, "A handy short definition of all science fiction might read: realistic speculation about possible future events, based solidly on adequate knowledge of the real world and present, on a thorough understanding of the nature and significance of the scientific method."Lester del Rey wrote, "Even the devoted aficionado or fan—has a hard time trying to explain what science fiction is," and that the reason for there not being a "full satisfactory definition" is that "there are no delineated limits to science fiction."
Author and editor Damon Knight summed up the difficulty, saying "science fiction is what we point to when we say it." Mark C. Glassy described the definition of science fiction as U. S. Supreme Court Justice Potter Stewart did with the definition of pornography: "I know it when I see it." Science fiction had its beginnings in a time when the line between myth and fact was arguably more blurred than the present day. Written in the 2nd century CE by the satirist Lucian, A True Story contains many themes and tropes that are characteristic of contemporary science fiction, including travel to other worlds, extraterrestrial lifeforms, interplanetary warfare, artificial life; some consider it the first science-fiction novel. Some of the stories from The Arabian Nights, along with the 10th-century The Tale of the Bamboo Cutter and Ibn al-Nafis's 13th-century Theologus Autodidactus contain elements of science fiction. Products of the Age of Reason and the development of modern science itself, Johannes Kepler's Somnium, Francis Bacon's New Atlantis, Cyrano de Bergerac's Comical History of the States and Empires of the Moon and The States and Empires of the Sun, Margaret Cavendish's "The Blazing World", Jonathan Swift's Gulliver's Travels, Ludvig Holberg's Nicolai Klimii Iter Subterraneum and Voltaire's Micromégas are regarded as some of the first true science-fantasy works.
Indeed, Isaac Asimov and Carl Sagan considered Somnium the first science-fiction story. Following the 18th-century development of the novel as a literary form, Mary Shelley's books Frankenstein and The Last Man helped define the form of the science-fiction novel. Brian Aldiss has argued. Edgar Allan Poe wrote several stories considered science fiction, including "The Unparalleled Adventure of One Hans Pfaall" which featured a trip to the Moon. Jules Verne was noted for his attention to detail and scientific accuracy Twenty Thousand Leagues Under the Sea which predicted the contemporary nuclear submarine. In 1887, the novel El anacronópete by Spanish author Enrique Gaspar y Rimbau introduced the first time machine. Many critics consider H. G. Wells one of science fiction's most important authors, or "the Shakespeare of science fiction." His notable science-fiction works include The Time Machine, The Island of Doctor Moreau, The Invisible Man, The War of the Worlds. His science fiction imagined alien invasion, biological engineering and time travel.
In his non-fiction futurologist works he predicted the advent of airplanes, military tanks, nuclear weapons, satellite television, space travel, something resembling the World Wide Web. In 1912, Edgar Rice Burroughs published A Princess of Mars, the first of his three-decade-long planetary romance series of Barsoom novels, set on Mars and featuring John Carter as the hero. In 1926, Hugo Gernsback published the first American science-fiction magazine, Amazing Stories, in which he wrote: By'scientifiction' I mean the Jules Verne, H. G. Wells and Edgar Allan Poe type of story—a charming romance intermingled with scientific fact and prophetic vision... Not only do these amazing tales make tremendously interesting reading—they are always instructive, they supply knowledge... in a palatable form... New adventures pictured for us in the scientifiction of today are not at all impossible of realization tomorrow... Many great science stories destined to be of historical interest are still to be written...
Posterity will point to them as having blazed a new trail, not only in literature and fiction, but progress as well. In 1928, E. E. "Doc" Smith's first published work, The Skylark of Space, written in collaboration with Lee Hawkins Garby, appeared in Amazing Stories. It is called the first great space opera; the same year, Philip Francis Nowlan's original Buck Rogers story, Armageddon 2419 appeared in Amazing Stories. This was followed by the first serious science-fiction comic. In 1937, John W. Campbell became editor of Astounding Science Fiction, an event, sometimes conside
The Voyager program is an American scientific program that employs two robotic probes, Voyager 1 and Voyager 2, to study the outer Solar System. The probes were launched in 1977 to take advantage of a favorable alignment of Jupiter, Saturn and Neptune. Although their original mission was to study only the planetary systems of Jupiter and Saturn, Voyager 2 continued on to Uranus and Neptune; the Voyagers now explore the outer boundary of the heliosphere in interstellar space. Neither Uranus nor Neptune has been visited by a probe other than Voyager 2. On 25 August 2012, data from Voyager 1 indicated that it had become the first human-made object to enter interstellar space, traveling "further than anyone, or anything, in history"; as of 2013, Voyager 1 was moving with a velocity of 17 kilometers per second relative to the Sun. On 5 November 2018, data from Voyager 2 indicated that it had entered interstellar space. Data and photographs collected by the Voyagers' cameras and other instruments, revealed unknown details about each of the four giant planets and their moons.
Close-up images from the spacecraft charted Jupiter's complex cloud forms and storm systems and discovered volcanic activity on its moon Io. Saturn's rings were found to have enigmatic braids and spokes and to be accompanied by myriad "ringlets". At Uranus, Voyager 2 discovered a substantial magnetic field around ten more moons, its flyby of Neptune uncovered three rings and six hitherto unknown moons, a planetary magnetic field and complex distributed auroras. Voyager 2 is the only spacecraft to have visited the two ice giants. In August 2018, NASA confirmed, based on results by the New Horizons spacecraft, of a "hydrogen wall" at the outer edges of the Solar System, first detected in 1992 by the two Voyager spacecraft; the Voyager spacecraft were built at the Jet Propulsion Laboratory in Southern California and they were funded by the National Aeronautics and Space Administration, which financed their launches from Cape Canaveral, their tracking and everything else concerning the probes. The cost of the original program was $865 million, with the later-added Voyager Interstellar Mission costing an extra $30 million.
The two Voyager space probes were conceived as part of the Mariner program, they were thus named Mariner 11 and Mariner 12. They were moved into a separate program named "Mariner Jupiter-Saturn" renamed the Voyager Program because it was thought that the design of the two space probes had progressed sufficiently beyond that of the Mariner family to merit a separate name; the Voyager Program was similar to the Planetary Grand Tour planned during the late 1960s and early 70s. The Grand Tour would take advantage of an alignment of the outer planets discovered by Gary Flandro, an aerospace engineer at the Jet Propulsion Laboratory; this alignment, which occurs once every 175 years, would occur in the late 1970s and make it possible to use gravitational assists to explore Jupiter, Uranus and Pluto. The Planetary Grand Tour was to send several pairs of probes to fly by all the outer planets along various trajectories, including Jupiter-Saturn-Pluto and Jupiter-Uranus-Neptune. Limited funding ended the Grand Tour program, but elements were incorporated into the Voyager Program, which fulfilled many of the flyby objectives of the Grand Tour except a visit to Pluto.
Voyager 2 was the first to launch. Its trajectory was designed to allow flybys of Jupiter, Saturn and Neptune. Voyager 1 was launched after Voyager 2, but along a shorter and faster trajectory, designed to provide an optimal flyby of Saturn's moon Titan, known to be quite large and to possess a dense atmosphere; this encounter sent Voyager 1 out of the plane of the ecliptic, ending its planetary science mission. Had Voyager 1 been unable to perform the Titan flyby, the trajectory of Voyager 2 could have been altered to explore Titan, forgoing any visit to Uranus and Neptune. Voyager 1 was not launched on a trajectory that would have allowed it to continue to Uranus and Neptune, but could have continued from Saturn to Pluto without exploring Titan. During the 1990s, Voyager 1 overtook the slower deep-space probes Pioneer 10 and Pioneer 11 to become the most distant human-made object from Earth, a record that it will keep for the foreseeable future; the New Horizons probe, which had a higher launch velocity than Voyager 1, is traveling more due to the extra speed Voyager 1 gained from its flybys of Jupiter and Saturn.
Voyager 1 and Pioneer 10 are the most separated human made objects anywhere, since they are traveling in opposite directions from the Solar System. In December 2004, Voyager 1 crossed the termination shock, where the solar wind is slowed to subsonic speed, entered the heliosheath, where the solar wind is compressed and made turbulent due to interactions with the interstellar medium. On December 10, 2007, Voyager 2 reached the termination shock, about 1 billion miles closer to the Sun than from where Voyager 1 first crossed it, indicating that the Solar System is asymmetrical. In 2010 Voyager 1 reported that the outward velocity of the solar wind had dropped to zero, scientists predicted it was nearing interstellar space. In 2011, data from the Voyagers determined that the heliosheath is not smooth, but filled with giant magnetic bubbles, theorized to form when the magnetic field of the Sun becomes warped at the edge of the Solar System. On 15 June 2012, scientists at NASA reported that Voyager 1 was close to entering interstellar space, indicated by a sharp rise in high-energy particl
Archaeology, or archeology, is the study of human activity through the recovery and analysis of material culture. The archaeological record consists of artifacts, biofacts or ecofacts and cultural landscapes. Archaeology can be considered a branch of the humanities. In North America archaeology is a sub-field of anthropology, while in Europe it is viewed as either a discipline in its own right or a sub-field of other disciplines. Archaeologists study human prehistory and history, from the development of the first stone tools at Lomekwi in East Africa 3.3 million years ago up until recent decades. Archaeology is distinct from palaeontology, the study of fossil remains, it is important for learning about prehistoric societies, for whom there may be no written records to study. Prehistory includes over 99% of the human past, from the Paleolithic until the advent of literacy in societies across the world. Archaeology has various goals, which range from understanding culture history to reconstructing past lifeways to documenting and explaining changes in human societies through time.
The discipline involves surveying and analysis of data collected to learn more about the past. In broad scope, archaeology relies on cross-disciplinary research, it draws upon anthropology, art history, ethnology, geology, literary history, semiology, textual criticism, information sciences, statistics, paleography, paleontology and paleobotany. Archaeology developed out of antiquarianism in Europe during the 19th century, has since become a discipline practiced across the world. Archaeology has been used by nation-states to create particular visions of the past. Since its early development, various specific sub-disciplines of archaeology have developed, including maritime archaeology, feminist archaeology and archaeoastronomy, numerous different scientific techniques have been developed to aid archaeological investigation. Nonetheless, archaeologists face many problems, such as dealing with pseudoarchaeology, the looting of artifacts, a lack of public interest, opposition to the excavation of human remains.
The science of archaeology grew out of the older multi-disciplinary study known as antiquarianism. Antiquarians studied history with particular attention to ancient artifacts and manuscripts, as well as historical sites. Antiquarianism focused on the empirical evidence that existed for the understanding of the past, encapsulated in the motto of the 18th-century antiquary, Sir Richard Colt Hoare, "We speak from facts not theory". Tentative steps towards the systematization of archaeology as a science took place during the Enlightenment era in Europe in the 17th and 18th centuries. In Europe, philosophical interest in the remains of Greco-Roman civilization and the rediscovery of classical culture began in the late Middle Age. Flavio Biondo, an Italian Renaissance humanist historian, created a systematic guide to the ruins and topography of ancient Rome in the early 15th century, for which he has been called an early founder of archaeology. Antiquarians of the 16th century, including John Leland and William Camden, conducted surveys of the English countryside, drawing and interpreting the monuments that they encountered.
One of the first sites to undergo archaeological excavation was Stonehenge and other megalithic monuments in England. John Aubrey was a pioneer archaeologist who recorded numerous megalithic and other field monuments in southern England, he was ahead of his time in the analysis of his findings. He attempted to chart the chronological stylistic evolution of handwriting, medieval architecture and shield-shapes. Excavations were carried out by the Spanish military engineer Roque Joaquín de Alcubierre in the ancient towns of Pompeii and Herculaneum, both of, covered by ash during the Eruption of Mount Vesuvius in AD 79; these excavations began in 1748 in Pompeii, while in Herculaneum they began in 1738. The discovery of entire towns, complete with utensils and human shapes, as well the unearthing of frescos, had a big impact throughout Europe. However, prior to the development of modern techniques, excavations tended to be haphazard; the father of archaeological excavation was William Cunnington. He undertook excavations in Wiltshire from around 1798.
Cunnington made meticulous recordings of Neolithic and Bronze Age barrows, the terms he used to categorize and describe them are still used by archaeologists today. One of the major achievements of 19th-century archaeology was the development of stratigraphy; the idea of overlapping strata tracing back to successive periods was borrowed from the new geological and paleontological work of scholars like William Smith, James Hutton and Charles Lyell. The application of stratigraphy to archaeology first took place with the excavations of prehistorical and Bronze Age sites. In the third and fourth decades of the 19th-century, archaeologists like Jacques Boucher de Perthes and Christian Jürgensen Thomsen began to put the artifacts they had found in chronological order. A major figure in the development of archaeology into a rigorous science was the army officer and ethnologist, Augustus Pitt Rivers, who began excavations on his land in England in the 1880s, his approach was methodical by the standards of the time, he is regarded as the first scientific archaeologist.
He arranged his artifacts by type or "typologically, within types by date or "chronologically"