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An electromagnetic field (also EM field or EMF) is a classical (i.e. non-quantum) field produced by moving electric charges. It is the field described by classical electrodynamics (a classical field theory) and is the classical counterpart to the quantized electromagnetic field tensor in quantum electrodynamics (a quantum field theory). The electromagnetic field propagates at the speed of light (in fact, this field can be identified as light) and interacts with charges and currents. Its quantum counterpart is one of the four fundamental forces of nature (the others are gravitation, weak interaction and strong interaction.) The field can be viewed as the combination of an electric field and a magnetic field. The electric field is produced by stationary charges, and the magnetic field by moving charges (electric currents); these two are often described as the sources of the field. The way in which charges and currents interact with the electromagnetic field is described by Maxwell's equations (which also describes how time-varying field can produce other fields, and explains why electromagnetic radiation doesn't need any medium for propagation) and...

James Dewey Watson (born April 6, 1928) is an American molecular biologist, geneticist, and zoologist. In 1953, he co-authored with Francis Crick the academic paper proposing the double helix structure of the DNA molecule. Watson, Crick and Maurice Wilkins were awarded the 1962 Nobel Prize in Physiology or Medicine "for their discoveries concerning the molecular structure of nucleic acids and its significance for information transfer in living material". In subsequent years, it has been recognized that Watson and his colleagues did not properly attribute colleague Rosalind Franklin for her contributions to the discovery of the double helix structure.Watson earned degrees at the University of Chicago (BS, 1947) and Indiana University (PhD, 1950). Following a post-doctoral year at the University of Copenhagen with Herman Kalckar and Ole Maaløe, Watson worked at the University of Cambridge's Cavendish Laboratory in England, where he first met his future collaborator Francis Crick. From 1956 to 1976, Watson was on the faculty of the Harvard University Biology Department, promoting research in molecular biology. From 1968, Watson served...

The Flammarion engraving is a wood engraving by an unknown artist, so named because its first documented appearance is in Camille Flammarion's 1888 book L'atmosphère : météorologie populaire ("The Atmosphere: Popular Meteorology"). The wood engraving has often, but erroneously, been referred to as a woodcut. It has been used as a metaphorical illustration of either the scientific or the mystical quests for knowledge. Description The print depicts a man, clothed in a long robe and carrying a staff, who is at the edge of the Earth, where it meets the sky. He kneels down and passes his head, shoulders, and right arm through the star-studded sky, discovering a marvellous realm of circling clouds, fires and suns beyond the heavens. One of the elements of the cosmic machinery bears a strong resemblance to traditional pictorial representations of the "wheel in the middle of a wheel" described in the visions of the Hebrew prophet Ezekiel. The caption that accompanies the engraving in Flammarion's book reads: A missionary of the Middle...

Romanesque art is the art of Europe from approximately 1000 AD to the rise of the Gothic style in the 12th century, or later depending on region. The preceding period is known as the Pre-Romanesque period. The term was invented by 19th-century art historians, especially for Romanesque architecture, which retained many basic features of Roman architectural style – most notably round-headed arches, but also barrel vaults, apses, and acanthus-leaf decoration – but had also developed many very different characteristics. In Southern France, Spain, and Italy there was an architectural continuity with the Late Antique, but the Romanesque style was the first style to spread across the whole of Catholic Europe, from Sicily to Scandinavia. Romanesque art was also greatly influenced by Byzantine art, especially in painting, and by the anti-classical energy of the decoration of the Insular art of the British Isles. From these elements was forged a highly innovative and coherent style. Characteristics Outside Romanesque architecture, the art of the period was characterised by a vigorous style in both sculpture and painting. The latter...

Romanesque architecture is an architectural style of medieval Europe characterized by semi-circular arches. There is no consensus for the beginning date of the Romanesque style, with proposals ranging from the 6th to the 11th century, this later date being the most commonly held. In the 12th century it developed into the Gothic style, marked by pointed arches. Examples of Romanesque architecture can be found across the continent, making it the first pan-European architectural style since Imperial Roman architecture. The Romanesque style in England and Sicily is traditionally referred to as Norman architecture. Combining features of ancient Roman and Byzantine buildings and other local traditions, Romanesque architecture is known by its massive quality, thick walls, round arches, sturdy pillars, barrel vaults, large towers and decorative arcading. Each building has clearly defined forms, frequently of very regular, symmetrical plan; the overall appearance is one of simplicity when compared with the Gothic buildings that were to follow. The style can be identified right across Europe, despite regional characteristics and different materials...

Object definition, anything that is visible or tangible and is relatively stable in form. See more.

of, relating to, or having three dimensions; giving the illusion of depth or varying distances —used especially of an image or a pictorial representation on a two-dimensional medium when this illusion is enhanced by stereoscopic means… See the full definition

A global catastrophic risk or a doomsday scenario is a hypothetical future event that could damage human well-being and animal well being on a global scale, even endangering or destroying modern civilization. An event that could cause human extinction or permanently and drastically curtail humanity's potential is known as an "existential risk."Over the last two decades, a number of academic and non-profit organizations have been established to research global catastrophic and existential risks, formulate potential mitigation measures and either advocate for or implement these measures. Definition and classification Defining global catastrophic risks The term global catastrophic risk "lacks a sharp definition", and generally refers (loosely) to a risk that could inflict "serious damage to human well-being on a global scale".Humanity has suffered large catastrophes before. Some of these have caused serious...