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1978 In Science
The year 1978 in science and technology involved some significant events, listed below. Astronomy and space science * March 2 – Vladimír Remek becomes the first Czechoslovak in space and the first cosmonaut from a country other than the Soviet Union or the United States, onboard Soyuz 28. * June 22 – James W. Christy at the United States Naval Observatory discovers Charon (moon), Charon, the first moon of Pluto identified. * October – It is first proposed that Janus (moon), Janus and Epimetheus (moon), Epimetheus are two separate moons of Saturn sharing the same orbit. Computer science * February 16 – The first computer bulletin board system is created (CBBS in Chicago, Illinois). * The RSA (algorithm), RSA algorithm for public-key cryptography, based on the factoring problem, is first publicly described by Ron Rivest, Adi Shamir and Leonard Adleman. Geophysics * James Byerlee determines Byerlee's law which gives the stress (physics), stress circumstances in the crust ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Factoring Problem
In mathematics, integer factorization is the decomposition of a positive integer into a product of integers. Every positive integer greater than 1 is either the product of two or more integer factors greater than 1, in which case it is a composite number, or it is not, in which case it is a prime number. For example, is a composite number because , but is a prime number because it cannot be decomposed in this way. If one of the factors is composite, it can in turn be written as a product of smaller factors, for example . Continuing this process until every factor is prime is called prime factorization; the result is always unique up to the order of the factors by the prime factorization theorem. To factorize a small integer using mental or pen-and-paper arithmetic, the simplest method is trial division: checking if the number is divisible by prime numbers , , , and so on, up to the square root of . For larger numbers, especially when using a computer, various more sophisti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BBC Television
BBC Television is a service of the BBC. The corporation has operated a Public service broadcasting in the United Kingdom, public broadcast television service in the United Kingdom, under the terms of a royal charter, since 1 January 1927. It produced television programmes from its own studios from 1932, although the start of its regular service of television broadcasts is dated to 2 November 1936. The BBC's domestic television channels have no commercial advertising and collectively they accounted for more than 30% of all UK viewing in 2013. The services are funded by a television licence. As a result of the 2016 Licence Fee settlement, the BBC Television division was split, with in-house television production being separated into a new division called BBC Studios and the remaining parts of television (channels and genre commissioning, BBC Sport and BBC iPlayer) being renamed BBC Content. History of BBC Television The BBC operates several television networks, television stati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Connections (British Documentary)
''Connections'' is a science education television series created, written, and presented by British science historian James Burke. The series was produced and directed by Mick Jackson of the BBC Science and Features Department and first aired in 1978 (UK) and 1979 (US). It took an interdisciplinary approach to the history of science and invention, and demonstrated how various discoveries, scientific achievements, and historical world events were built from one another successively in an interconnected way to bring about particular aspects of modern technology. The series was noted for Burke's crisp and enthusiastic presentation (and dry humour), historical re-enactments, and intricate working models. The popular success of the series led to the production of '' The Day the Universe Changed'' (1985), a similar programme, but showing a more linear history of several important scientific developments and their more philosophic impact on Western civilisation. Years later, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
History Of Science
The history of science covers the development of science from ancient history, ancient times to the present. It encompasses all three major branches of science: natural science, natural, social science, social, and formal science, formal. Protoscience, Science in the ancient world, early sciences, and natural philosophies such as alchemy and astrology that existed during the Bronze Age, Iron Age, classical antiquity and the Middle Ages, declined during the early modern period after the establishment of formal disciplines of science in the Age of Enlightenment. The earliest roots of scientific thinking and practice can be traced to Ancient Egypt and Mesopotamia during the 3rd and 2nd millennia BCE. These civilizations' contributions to mathematics, astronomy, and medicine influenced later Greek natural philosophy of Science in classical antiquity, classical antiquity, wherein formal attempts were made to provide explanations of events in the Universe, physical world based on n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
James Burke (science Historian)
James Burke (born 22 December 1936) is a broadcaster, science historian, author, and television producer. He was one of the main presenters of the BBC1 science series '' Tomorrow's World'' from 1965 to 1971 and created and presented the television series '' Connections'' (1978), and its more philosophical sequel '' The Day the Universe Changed'' (1985), about the history of science and technology. ''The Washington Post'' has called him "one of the most intriguing minds in the Western world". Early life Burke was born in Derry, Northern Ireland. During World War II he was evacuated to Downhill, County Londonderry where he lived between the ages of 4 and 9. When his father returned home after the war, the family moved to Kent, England, where James Burke attended Maidstone Grammar School. He then served in the Royal Air Force (RAF) from 1955 to 1957 before being accepted at Jesus College, Oxford, where he studied Middle English, obtaining BA and MA degrees. Personal life B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geological Fault
Geology (). is a branch of natural science concerned with the Earth and other astronomical objects, the rocks of which they are composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth sciences, including hydrology. It is integrated with Earth system science and planetary science. Geology describes the structure of the Earth on and beneath its surface and the processes that have shaped that structure. Geologists study the mineralogical composition of rocks in order to get insight into their history of formation. Geology determines the relative ages of rocks found at a given location; geochemistry (a branch of geology) determines their absolute ages. By combining various petrological, crystallographic, and paleontological tools, geologists are able to chronicle the geological history of the Earth as a whole. One aspect is to demonstrate the age of the Earth. Geology provides evidence for plate tectonics, the ev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fracture
Fracture is the appearance of a crack or complete separation of an object or material into two or more pieces under the action of stress (mechanics), stress. The fracture of a solid usually occurs due to the development of certain displacement discontinuity surfaces within the solid. If a displacement develops perpendicular to the surface, it is called a normal tensile crack or simply a crack; if a displacement develops tangentially, it is called a shear crack, slip band, or dislocation. #Brittle, Brittle fractures occur without any apparent deformation before fracture. #Ductile, Ductile fractures occur after visible deformation. Fracture strength, or breaking strength, is the stress when a specimen fails or fractures. The detailed understanding of how a fracture occurs and develops in materials is the object of fracture mechanics. Strength Fracture strength, also known as breaking strength, is the stress at which a specimen structural integrity and failure, fails via fra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crust (geology)
In geology, the crust is the outermost solid shell of a planet, dwarf planet, or natural satellite. It is usually distinguished from the underlying mantle by its chemical makeup; however, in the case of icy satellites, it may be defined based on its phase (solid crust vs. liquid mantle). The crusts of Earth, Mercury, Venus, Mars, Io, the Moon and other planetary bodies formed via igneous processes and were later modified by erosion, impact cratering, volcanism, and sedimentation. Most terrestrial planets have fairly uniform crusts. Earth, however, has two distinct types: continental crust and oceanic crust. These two types have different chemical compositions and physical properties and were formed by different geological processes. Types of crust Planetary geologists divide crust into three categories based on how and when it formed. Primary crust / primordial crust This is a planet's "original" crust. It forms from solidification of a magma ocean. Toward the end o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stress (physics)
In continuum mechanics, stress is a physical quantity that describes Force, forces present during Deformation (physics), deformation. For example, an object being pulled apart, such as a stretched elastic band, is subject to Tension (physics), ''tensile'' stress and may undergo Elongation (materials science), elongation. An object being pushed together, such as a crumpled sponge, is subject to Compression (physics), ''compressive'' stress and may undergo shortening. The greater the force and the smaller the cross-sectional area of the body on which it acts, the greater the stress. Stress has Dimension (physics), dimension of force per area, with SI Units, SI units of newtons per square meter (N/m2) or Pascal (unit), pascal (Pa). Stress expresses the internal forces that neighbouring particles of a continuous material exert on each other, while Strain (mechanics), ''strain'' is the measure of the relative deformation (mechanics), deformation of the material. For example, when a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Byerlee's Law
In rheology, Byerlee's law, also known as Byerlee's friction law concerns the shear stress (τ) required to slide one rock over another. The rocks have macroscopically flat surfaces, but the surfaces have small asperities that make them "rough." For a given experiment and at normal stresses (σn) below about 2000 bars (200 MPa) the shear stress increases approximately linearly with the normal stress (τ = 0.85 σn, where τ and σn is in units of MPa) and is highly dependent on rock type and the character (roughness) of the surfaces, see Mohr-Coulomb friction law. Byerlee's law states that with increased normal stress the required shear stress continues to increase, but the ''rate'' of increase decreases (τ = 50 + 0.6σn), where τ and σn are in units of MPa, and becomes nearly independent of rock type. The law describes an important property of crustal rock, and can be used to determine when slip along a geological fault takes place. The law is named after the American geop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communications Of The ACM
''Communications of the ACM'' (''CACM'') is the monthly journal of the Association for Computing Machinery (ACM). History It was established in 1958, with Saul Rosen as its first managing editor. It is sent to all ACM members. Articles are intended for readers with backgrounds in all areas of computer science and information systems. The focus is on the practical implications of advances in information technology and associated management issues; ACM also publishes a variety of more theoretical journals. The magazine straddles the boundary of a science magazine, trade magazine, and a scientific journal. While the content is subject to peer review, the articles published are often summaries of research that may also be published elsewhere. Material published must be accessible and relevant to a broad readership. From 1960 onward, ''CACM'' also published algorithms, expressed in ALGOL. The collection of algorithms later became known as the Collected Algorithms of the ACM. CA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
