Communication is the act of conveying meanings from one entity or group to another through the use of mutually understood signs and semiotic rules. The main steps inherent to all communication are: The formation of communicative motivation or reason. Message composition. Message encoding. Transmission of the encoded message as a sequence of signals using a specific channel or medium. Noise sources such as natural forces and in some cases human activity begin influencing the quality of signals propagating from the sender to one or more receivers. Reception of signals and reassembling of the encoded message from a sequence of received signals. Decoding of the reassembled encoded message. Interpretation and making sense of the presumed original message; the scientific study of communication can be divided into: Information theory which studies the quantification and communication of information in general. The channel of communication can be visual, auditory and haptic, electromagnetic, or biochemical.
Human communication is unique for its extensive use of abstract language. Development of civilization has been linked with progress in telecommunication. Nonverbal communication describes the processes of conveying a type of information in the form of non-linguistic representations. Examples of nonverbal communication include haptic communication, chronemic communication, body language, facial expressions, eye contact, how one dresses. Nonverbal communication relates to the intent of a message. Examples of intent are voluntary, intentional movements like shaking a hand or winking, as well as involuntary, such as sweating. Speech contains nonverbal elements known as paralanguage, e.g. rhythm, intonation and stress. It establishes trust. Written texts include nonverbal elements such as handwriting style, the spatial arrangement of words and the use of emoticons to convey emotion. Nonverbal communication demonstrates one of Paul Wazlawick's laws: you cannot not communicate. Once proximity has formed awareness, living creatures begin interpreting.
Some of the functions of nonverbal communication in humans are to complement and illustrate, to reinforce and emphasize, to replace and substitute, to control and regulate, to contradict the denovative message. Nonverbal cues are relied on to express communication and to interpret others' communication and can replace or substitute verbal messages. However, non-verbal communication is ambiguous; when verbal messages contradict non-verbal messages, observation of non-verbal behaviour is relied on to judge another's attitudes and feelings, rather than assuming the truth of the verbal message alone. There are several reasons as to why non-verbal communication plays a vital role in communication: "Non-verbal communication is omnipresent." They are included in every single communication act. To have total communication, all non-verbal channels such as the body, voice, touch, distance and other environmental forces must be engaged during face-to-face interaction. Written communication can have non-verbal attributes.
E-mails and web chats allow an individual's the option to change text font colours, stationary and capitalization in order to capture non-verbal cues into a verbal medium. "Non-verbal behaviours are multifunctional." Many different non-verbal channels are engaged at the same time in communication acts and allow the chance for simultaneous messages to be sent and received. "Non-verbal behaviours may form a universal language system." Smiling, pointing and glaring are non-verbal behaviours that are used and understood by people regardless of nationality. Such non-verbal signals allow the most basic form of communication when verbal communication is not effective due to language barriers. Verbal communication is the written conveyance of a message. Human language can be defined as a system of symbols and the grammars by which the symbols are manipulated; the word "language" refers to common properties of languages. Language learning occurs most intensively during human childhood. Most of the thousands of human languages use patterns of sound or gesture for symbols which enable communication with others around them.
Languages tend to share certain properties. There is no defined line between a dialect. Constructed languages such as Esperanto, programming languages, various mathematical formalism is not restricted to the properties shared by human languages; as mentioned, language can be characterized as symbolic. Charles Ogden and I. A Richards developed The Triangle of Meaning model to explain the symbol, the referent, the meaning; the properties of language are governed by rules. Language follows phonological rules, syntactic rules, semantic rules, pragmatic rules; the meanings that are attached to words can be otherwise known as denotative.
Construction is the process of constructing a building or infrastructure. Construction differs from manufacturing in that manufacturing involves mass production of similar items without a designated purchaser, while construction takes place on location for a known client. Construction as an industry comprises six to nine percent of the gross domestic product of developed countries. Construction starts with planning and financing. Large-scale construction requires collaboration across multiple disciplines. A project manager manages the job, a construction manager, design engineer, construction engineer or architect supervises it; those involved with the design and execution must consider zoning requirements, environmental impact of the job, budgeting, construction-site safety and transportation of building materials, inconvenience to the public caused by construction delays and bidding. Large construction projects are sometimes referred to as megaprojects. Construction is a general term meaning the art and science to form objects, systems, or organizations, comes from Latin constructio and Old French construction.
To construct is the verb: the act of building, the noun construction: how a building was built, the nature of its structure. In general, there are three sectors of construction: buildings and industrial. Building construction is further divided into residential and non-residential. Infrastructure is called heavy civil or heavy engineering that includes large public works, bridges, railways, water or wastewater and utility distribution. Industrial construction includes refineries, process chemical, power generation and manufacturing plants. There are other ways to break the industry into sectors or markets. Engineering News-Record, a trade magazine for the construction industry, each year compiles and reports data about the size of design and construction companies. In 2014, ENR compiled the data in nine market segments divided as transportation, buildings, industrial, manufacturing, sewer/waste, hazardous waste and a tenth category for other projects. In their reporting, they used data on transportation, hazardous waste and water to rank firms as heavy contractors.
The Standard Industrial Classification and the newer North American Industry Classification System have a classification system for companies that perform or engage in construction. To recognize the differences of companies in this sector, it is divided into three subsectors: building construction and civil engineering construction, specialty trade contractors. There are categories for construction service firms and construction managers. Building construction is the process of adding structure to real property or construction of buildings; the majority of building construction jobs are small renovations, such as addition of a room, or renovation of a bathroom. The owner of the property acts as laborer and design team for the entire project. Although building construction projects consist of common elements such as design, financial and legal considerations, projects of varying sizes may reach undesirable end results, such as structural collapse, cost overruns, and/or litigation. For this reason, those with experience in the field make detailed plans and maintain careful oversight during the project to ensure a positive outcome.
Commercial building construction is procured or publicly utilizing various delivery methodologies, including cost estimating, hard bid, negotiated price, management contracting, construction management-at-risk, design & build and design-build bridging. Residential construction practices and resources must conform to local building authority regulations and codes of practice. Materials available in the area dictate the construction materials used. Cost of construction on a per square meter basis for houses can vary based on site conditions, local regulations, economies of scale and the availability of skilled tradesmen. Residential construction as well as other types of construction can generate waste such that planning is required. According to McKinsey research, productivity growth per worker in construction has lagged behind many other industries across different countries including in the United States and in European countries. In the United States, construction productivity per worker has declined by half since the 1960s.
The most popular method of residential construction in North America is wood-framed construction. Typical construction steps for a single-family or small multi-family house are: Obtain an engineered soil test of lot where construction is planned. From an engineer or company specializing in soil testing. Develop floor plans and obtain a materials list for estimations Obtain structural engineered plans for foundation and structure. To be completed by either a licensed engineer or architect. To include both a foundation and framing plan. Obtain lot survey Obtain government building approval if necessary If required obtain approval from HOA or ARC Clear the building site Survey to stake out for the foun
The European Organization for Nuclear Research, known as CERN, is a European research organization that operates the largest particle physics laboratory in the world. Established in 1954, the organization is based in a northwest suburb of Geneva on the Franco–Swiss border and has 23 member states. Israel is the only non-European country granted full membership. CERN is an official United Nations Observer; the acronym CERN is used to refer to the laboratory, which in 2016 had 2,500 scientific and administrative staff members, hosted about 12,000 users. In the same year, CERN generated 49 petabytes of data. CERN's main function is to provide the particle accelerators and other infrastructure needed for high-energy physics research – as a result, numerous experiments have been constructed at CERN through international collaborations; the main site at Meyrin hosts a large computing facility, used to store and analyse data from experiments, as well as simulate events. Researchers need remote access to these facilities, so the lab has been a major wide area network hub.
CERN is the birthplace of the World Wide Web. The convention establishing CERN was ratified on 29 September 1954 by 12 countries in Western Europe; the acronym CERN represented the French words for Conseil Européen pour la Recherche Nucléaire, a provisional council for building the laboratory, established by 12 European governments in 1952. The acronym was retained for the new laboratory after the provisional council was dissolved though the name changed to the current Organisation Européenne pour la Recherche Nucléaire in 1954. According to Lew Kowarski, a former director of CERN, when the name was changed, the abbreviation could have become the awkward OERN, Werner Heisenberg said that this could "still be CERN if the name is ". CERN's first president was Sir Benjamin Lockspeiser. Edoardo Amaldi was the general secretary of CERN at its early stages when operations were still provisional, while the first Director-General was Felix Bloch; the laboratory was devoted to the study of atomic nuclei, but was soon applied to higher-energy physics, concerned with the study of interactions between subatomic particles.
Therefore, the laboratory operated by CERN is referred to as the European laboratory for particle physics, which better describes the research being performed there. At the sixth session of the CERN Council, which took place in Paris from 29 June - 1 July 1953, the convention establishing the organization was signed, subject to ratification, by 12 states; the convention was ratified by the 12 founding Member States: Belgium, France, the Federal Republic of Germany, Italy, the Netherlands, Sweden, the United Kingdom, Yugoslavia. Several important achievements in particle physics have been made through experiments at CERN, they include: 1973: The discovery of neutral currents in the Gargamelle bubble chamber. In September 2011, CERN attracted media attention when the OPERA Collaboration reported the detection of faster-than-light neutrinos. Further tests showed that the results were flawed due to an incorrectly connected GPS synchronization cable; the 1984 Nobel Prize for Physics was awarded to Carlo Rubbia and Simon van der Meer for the developments that resulted in the discoveries of the W and Z bosons.
The 1992 Nobel Prize for Physics was awarded to CERN staff researcher Georges Charpak "for his invention and development of particle detectors, in particular the multiwire proportional chamber". The 2013 Nobel Prize for Physics was awarded to François Englert and Peter Higgs for the theoretical description of the Higgs mechanism in the year after the Higgs boson was found by CERN experiments; the World Wide Web began as a CERN project named ENQUIRE, initiated by Tim Berners-Lee in 1989 and Robert Cailliau in 1990. Berners-Lee and Cailliau were jointly honoured by the Association for Computing Machinery in 1995 for their contributions to the development of the World Wide Web. Based on the concept of hypertext, the project was intended to facilitate the sharing of information between researchers; the first website was activated in 1991. On 30 April 1993, CERN announced. A copy of the original first webpage, created by Berners-Lee, is still published on the World Wide Web Consortium's website as a historical document.
Prior to the Web's development, CERN had pioneered the introduction of Internet technology, beginning in the early 1980s. More CERN has become a facility for the development of grid computing, hosting projects including the Enabling Grids for E-sciencE and LHC Computing Grid, it hosts the CERN Internet Exchange Point, one of the two main internet exchange points in Switzerland. CERN operates a network of a decelerator; each machine in the chain increases the energy of particle beams before delivering them
International Business Machines Corporation is an American multinational information technology company headquartered in Armonk, New York, with operations in over 170 countries. The company began in 1911, founded in Endicott, New York, as the Computing-Tabulating-Recording Company and was renamed "International Business Machines" in 1924. IBM produces and sells computer hardware and software, provides hosting and consulting services in areas ranging from mainframe computers to nanotechnology. IBM is a major research organization, holding the record for most U. S. patents generated by a business for 26 consecutive years. Inventions by IBM include the automated teller machine, the floppy disk, the hard disk drive, the magnetic stripe card, the relational database, the SQL programming language, the UPC barcode, dynamic random-access memory; the IBM mainframe, exemplified by the System/360, was the dominant computing platform during the 1960s and 1970s. IBM has continually shifted business operations by focusing on higher-value, more profitable markets.
This includes spinning off printer manufacturer Lexmark in 1991 and the sale of personal computer and x86-based server businesses to Lenovo, acquiring companies such as PwC Consulting, SPSS, The Weather Company, Red Hat. In 2014, IBM announced that it would go "fabless", continuing to design semiconductors, but offloading manufacturing to GlobalFoundries. Nicknamed Big Blue, IBM is one of 30 companies included in the Dow Jones Industrial Average and one of the world's largest employers, with over 380,000 employees, known as "IBMers". At least 70% of IBMers are based outside the United States, the country with the largest number of IBMers is India. IBM employees have been awarded five Nobel Prizes, six Turing Awards, ten National Medals of Technology and five National Medals of Science. In the 1880s, technologies emerged that would form the core of International Business Machines. Julius E. Pitrap patented the computing scale in 1885. On June 16, 1911, their four companies were amalgamated in New York State by Charles Ranlett Flint forming a fifth company, the Computing-Tabulating-Recording Company based in Endicott, New York.
The five companies had offices and plants in Endicott and Binghamton, New York. C.. They manufactured machinery for sale and lease, ranging from commercial scales and industrial time recorders and cheese slicers, to tabulators and punched cards. Thomas J. Watson, Sr. fired from the National Cash Register Company by John Henry Patterson, called on Flint and, in 1914, was offered a position at CTR. Watson joined CTR as General Manager 11 months was made President when court cases relating to his time at NCR were resolved. Having learned Patterson's pioneering business practices, Watson proceeded to put the stamp of NCR onto CTR's companies, he implemented sales conventions, "generous sales incentives, a focus on customer service, an insistence on well-groomed, dark-suited salesmen and had an evangelical fervor for instilling company pride and loyalty in every worker". His favorite slogan, "THINK", became a mantra for each company's employees. During Watson's first four years, revenues reached $9 million and the company's operations expanded to Europe, South America and Australia.
Watson never liked the clumsy hyphenated name "Computing-Tabulating-Recording Company" and on February 14, 1924 chose to replace it with the more expansive title "International Business Machines". By 1933 most of the subsidiaries had been merged into one company, IBM. In 1937, IBM's tabulating equipment enabled organizations to process unprecedented amounts of data, its clients including the U. S. Government, during its first effort to maintain the employment records for 26 million people pursuant to the Social Security Act, the tracking of persecuted groups by Hitler's Third Reich through the German subsidiary Dehomag. In 1949, Thomas Watson, Sr. created IBM World Trade Corporation, a subsidiary of IBM focused on foreign operations. In 1952, he stepped down after 40 years at the company helm, his son Thomas Watson, Jr. was named president. In 1956, the company demonstrated the first practical example of artificial intelligence when Arthur L. Samuel of IBM's Poughkeepsie, New York, laboratory programmed an IBM 704 not to play checkers but "learn" from its own experience.
In 1957, the FORTRAN scientific programming language was developed. In 1961, IBM developed the SABRE reservation system for American Airlines and introduced the successful Selectric typewriter. In 1963, IBM employees and computers helped. A year it moved its corporate headquarters from New York City to Armonk, New York; the latter half of the 1960s saw IBM continue its support of space exploration, participating in the 1965 Gemini flights, 1966 Saturn flights and 1969 lunar mission. On April 7, 1964, IBM announced the first computer system family, the IBM System/360, it spanned the complete range of commercial and scientific applications from large to small, allowing companies for the first time to upgrade to models with greater computing capability without having to rewrite their applications. It was followed by the IBM System/370 in 1970. Together the
The National Aeronautics and Space Administration is an independent agency of the United States Federal Government responsible for the civilian space program, as well as aeronautics and aerospace research. NASA was established in 1958; the new agency was to have a distinctly civilian orientation, encouraging peaceful applications in space science. Since its establishment, most US space exploration efforts have been led by NASA, including the Apollo Moon landing missions, the Skylab space station, the Space Shuttle. NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle, the Space Launch System and Commercial Crew vehicles; the agency is responsible for the Launch Services Program which provides oversight of launch operations and countdown management for unmanned NASA launches. NASA science is focused on better understanding Earth through the Earth Observing System. From 1946, the National Advisory Committee for Aeronautics had been experimenting with rocket planes such as the supersonic Bell X-1.
In the early 1950s, there was challenge to launch an artificial satellite for the International Geophysical Year. An effort for this was the American Project Vanguard. After the Soviet launch of the world's first artificial satellite on October 4, 1957, the attention of the United States turned toward its own fledgling space efforts; the US Congress, alarmed by the perceived threat to national security and technological leadership, urged immediate and swift action. On January 12, 1958, NACA organized a "Special Committee on Space Technology", headed by Guyford Stever. On January 14, 1958, NACA Director Hugh Dryden published "A National Research Program for Space Technology" stating: It is of great urgency and importance to our country both from consideration of our prestige as a nation as well as military necessity that this challenge be met by an energetic program of research and development for the conquest of space... It is accordingly proposed that the scientific research be the responsibility of a national civilian agency...
NACA is capable, by rapid extension and expansion of its effort, of providing leadership in space technology. While this new federal agency would conduct all non-military space activity, the Advanced Research Projects Agency was created in February 1958 to develop space technology for military application. On July 29, 1958, Eisenhower signed the National Aeronautics and Space Act, establishing NASA; when it began operations on October 1, 1958, NASA absorbed the 43-year-old NACA intact. A NASA seal was approved by President Eisenhower in 1959. Elements of the Army Ballistic Missile Agency and the United States Naval Research Laboratory were incorporated into NASA. A significant contributor to NASA's entry into the Space Race with the Soviet Union was the technology from the German rocket program led by Wernher von Braun, now working for the Army Ballistic Missile Agency, which in turn incorporated the technology of American scientist Robert Goddard's earlier works. Earlier research efforts within the US Air Force and many of ARPA's early space programs were transferred to NASA.
In December 1958, NASA gained control of the Jet Propulsion Laboratory, a contractor facility operated by the California Institute of Technology. The agency's leader, NASA's administrator, is nominated by the President of the United States subject to approval of the US Senate, reports to him or her and serves as senior space science advisor. Though space exploration is ostensibly non-partisan, the appointee is associated with the President's political party, a new administrator is chosen when the Presidency changes parties; the only exceptions to this have been: Democrat Thomas O. Paine, acting administrator under Democrat Lyndon B. Johnson, stayed on while Republican Richard Nixon tried but failed to get one of his own choices to accept the job. Paine was confirmed by the Senate in March 1969 and served through September 1970. Republican James C. Fletcher, appointed by Nixon and confirmed in April 1971, stayed through May 1977 into the term of Democrat Jimmy Carter. Daniel Goldin was appointed by Republican George H. W. Bush and stayed through the entire administration of Democrat Bill Clinton.
Robert M. Lightfoot, Jr. associate administrator under Democrat Barack Obama, was kept on as acting administrator by Republican Donald Trump until Trump's own choice Jim Bridenstine, was confirmed in April 2018. Though the agency is independent, the survival or discontinuation of projects can depend directly on the will of the President; the first administrator was Dr. T. Keith Glennan appointed by Republican President Dwight D. Eisenhower. During his term he brought together the disparate projects in American space development research; the second administrator, James E. Webb, appointed by President John F. Kennedy, was a Democrat who first publicly served under President Harry S. Truman. In order to implement the Apollo program to achieve Kennedy's Moon la
Nuclear power is the use of nuclear reactions that release nuclear energy to generate heat, which most is used in steam turbines to produce electricity in a nuclear power plant. As a nuclear technology, nuclear power can be obtained from nuclear fission, nuclear decay and nuclear fusion reactions. Presently, the vast majority of electricity from nuclear power is produced by nuclear fission of uranium and plutonium. Nuclear decay processes are used in niche applications such as radioisotope thermoelectric generators. Generating electricity from fusion power remains at the focus of international research; this article deals with nuclear fission power for electricity generation. Civilian nuclear power supplied 2,488 terawatt hours of electricity in 2017, equivalent to about 10% of global electricity generation; as of April 2018, there are 449 civilian fission reactors in the world, with a combined electrical capacity of 394 gigawatt. As of 2018, there are 58 power reactors under construction and 154 reactors planned, with a combined capacity of 63 GW and 157 GW, respectively.
As of January 2019, 337 more reactors were proposed. Most reactors under construction are generation III reactors in Asia. Nuclear power is classified as a low greenhouse gas energy supply technology, along with renewable energy, by the Intergovernmental Panel on Climate Change. Since its commercialization in the 1970s, nuclear power has prevented about 1.84 million air pollution-related deaths and the emission of about 64 billion tonnes of carbon dioxide equivalent that would have otherwise resulted from the burning of fossil fuels. There is a debate about nuclear power. Proponents, such as the World Nuclear Association and Environmentalists for Nuclear Energy, contend that nuclear power is a safe, sustainable energy source that reduces carbon emissions. Opponents, such as Greenpeace and NIRS, contend that nuclear power poses many threats to people and the environment. Accidents in nuclear power plants include the Chernobyl disaster in the Soviet Union in 1986, the Fukushima Daiichi nuclear disaster in Japan in 2011, the more contained Three Mile Island accident in the United States in 1979.
There have been some nuclear submarine accidents. Nuclear reactors have caused the lowest number of fatalities per unit of energy generated when compared to fossil fuels and hydropower. Coal, natural gas and hydroelectricity each have caused a greater number of fatalities per unit of energy, due to air pollution and accidents. Collaboration on research and development towards greater efficiency and recycling of spent fuel in future generation IV reactors presently includes Euratom and the co-operation of more than 10 permanent member countries globally. In 1932 physicist Ernest Rutherford discovered that when lithium atoms were "split" by protons from a proton accelerator, immense amounts of energy were released in accordance with the principle of mass–energy equivalence. However, he and other nuclear physics pioneers Niels Bohr and Albert Einstein believed harnessing the power of the atom for practical purposes anytime in the near future was unlikely; the same year, his doctoral student James Chadwick discovered the neutron, recognized as a potential tool for nuclear experimentation because of its lack of an electric charge.
Experiments bombarding materials with neutrons led Frédéric and Irène Joliot-Curie to discover induced radioactivity in 1934, which allowed the creation of radium-like elements. Further work by Enrico Fermi in the 1930s focused on using slow neutrons to increase the effectiveness of induced radioactivity. Experiments bombarding uranium with neutrons led Fermi to believe he had created a new, transuranic element, dubbed hesperium. In 1938, German chemists Otto Hahn and Fritz Strassmann, along with Austrian physicist Lise Meitner and Meitner's nephew, Otto Robert Frisch, conducted experiments with the products of neutron-bombarded uranium, as a means of further investigating Fermi's claims, they determined that the tiny neutron split the nucleus of the massive uranium atoms into two equal pieces, contradicting Fermi. This was an surprising result: all other forms of nuclear decay involved only small changes to the mass of the nucleus, whereas this process—dubbed "fission" as a reference to biology—involved a complete rupture of the nucleus.
Numerous scientists, including Leó Szilárd, one of the first, recognized that if fission reactions released additional neutrons, a self-sustaining nuclear chain reaction could result. Once this was experimentally confirmed and announced by Frédéric Joliot-Curie in 1939, scientists in many countries petitioned their governments for support of nuclear fission research, just on the cusp of World War II, for the development of a nuclear weapon. In the United States, where Fermi and Szilárd had both emigrated, the discovery of the nuclear chain reaction led to the creation of the first man-made reactor, the research reactor known as Chicago Pile-1, which achieved self-sustaining power/criticality on December 2, 1942; the reactor's development was part of the Manhattan Project, the Allied effort to create atomic bombs during World War II. It led to the building of larger single-purpose production reactors, such as the X-10 Pile, for the production of weapons-grade plutonium for use in the first nuclear weapons.
The United States tested the first nuclear weapon in July 1945, the Trinity test, with the atomic bombings of Hiroshima and Nagasaki taking place one month later. In August 1945, the first distributed account of nuclear energy, in the form of the pocketbook The Atomic Age, discussed the peaceful future uses of nuclear energy and depicted a future where fo
Physics is the natural science that studies matter, its motion, behavior through space and time, that studies the related entities of energy and force. Physics is one of the most fundamental scientific disciplines, its main goal is to understand how the universe behaves. Physics is one of the oldest academic disciplines and, through its inclusion of astronomy the oldest. Over much of the past two millennia, chemistry and certain branches of mathematics, were a part of natural philosophy, but during the scientific revolution in the 17th century these natural sciences emerged as unique research endeavors in their own right. Physics intersects with many interdisciplinary areas of research, such as biophysics and quantum chemistry, the boundaries of physics which are not rigidly defined. New ideas in physics explain the fundamental mechanisms studied by other sciences and suggest new avenues of research in academic disciplines such as mathematics and philosophy. Advances in physics enable advances in new technologies.
For example, advances in the understanding of electromagnetism and nuclear physics led directly to the development of new products that have transformed modern-day society, such as television, domestic appliances, nuclear weapons. Astronomy is one of the oldest natural sciences. Early civilizations dating back to beyond 3000 BCE, such as the Sumerians, ancient Egyptians, the Indus Valley Civilization, had a predictive knowledge and a basic understanding of the motions of the Sun and stars; the stars and planets were worshipped, believed to represent gods. While the explanations for the observed positions of the stars were unscientific and lacking in evidence, these early observations laid the foundation for astronomy, as the stars were found to traverse great circles across the sky, which however did not explain the positions of the planets. According to Asger Aaboe, the origins of Western astronomy can be found in Mesopotamia, all Western efforts in the exact sciences are descended from late Babylonian astronomy.
Egyptian astronomers left monuments showing knowledge of the constellations and the motions of the celestial bodies, while Greek poet Homer wrote of various celestial objects in his Iliad and Odyssey. Natural philosophy has its origins in Greece during the Archaic period, when pre-Socratic philosophers like Thales rejected non-naturalistic explanations for natural phenomena and proclaimed that every event had a natural cause, they proposed ideas verified by reason and observation, many of their hypotheses proved successful in experiment. The Western Roman Empire fell in the fifth century, this resulted in a decline in intellectual pursuits in the western part of Europe. By contrast, the Eastern Roman Empire resisted the attacks from the barbarians, continued to advance various fields of learning, including physics. In the sixth century Isidore of Miletus created an important compilation of Archimedes' works that are copied in the Archimedes Palimpsest. In sixth century Europe John Philoponus, a Byzantine scholar, questioned Aristotle's teaching of physics and noting its flaws.
He introduced the theory of impetus. Aristotle's physics was not scrutinized until John Philoponus appeared, unlike Aristotle who based his physics on verbal argument, Philoponus relied on observation. On Aristotle's physics John Philoponus wrote: “But this is erroneous, our view may be corroborated by actual observation more than by any sort of verbal argument. For if you let fall from the same height two weights of which one is many times as heavy as the other, you will see that the ratio of the times required for the motion does not depend on the ratio of the weights, but that the difference in time is a small one, and so, if the difference in the weights is not considerable, that is, of one is, let us say, double the other, there will be no difference, or else an imperceptible difference, in time, though the difference in weight is by no means negligible, with one body weighing twice as much as the other”John Philoponus' criticism of Aristotelian principles of physics served as an inspiration for Galileo Galilei ten centuries during the Scientific Revolution.
Galileo cited Philoponus in his works when arguing that Aristotelian physics was flawed. In the 1300s Jean Buridan, a teacher in the faculty of arts at the University of Paris, developed the concept of impetus, it was a step toward the modern ideas of momentum. Islamic scholarship inherited Aristotelian physics from the Greeks and during the Islamic Golden Age developed it further placing emphasis on observation and a priori reasoning, developing early forms of the scientific method; the most notable innovations were in the field of optics and vision, which came from the works of many scientists like Ibn Sahl, Al-Kindi, Ibn al-Haytham, Al-Farisi and Avicenna. The most notable work was The Book of Optics, written by Ibn al-Haytham, in which he conclusively disproved the ancient Greek idea about vision, but came up with a new theory. In the book, he presented a study of the phenomenon of the camera obscura (his thousand-year-old