1.
Natural satellite
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A natural satellite or moon is, in the most common usage, an astronomical body that orbits a planet or minor planet. In the Solar System there are six planetary satellite systems containing 178 known natural satellites, four IAU-listed dwarf planets are also known to have natural satellites, Pluto, Haumea, Makemake, and Eris. As of January 2012, over 200 minor-planet moons have been discovered, the Earth–Moon system is unique in that the ratio of the mass of the Moon to the mass of Earth is much greater than that of any other natural-satellite–planet ratio in the Solar System. At 3,474 km across, Earths Moon is 0.27 times the diameter of Earth, the first known natural satellite was the Moon, but it was considered a planet until Copernicus introduction of heliocentrism in 1543. Until the discovery of the Galilean satellites in 1610, however, galileo chose to refer to his discoveries as Planetæ, but later discoverers chose other terms to distinguish them from the objects they orbited. The first to use of the satellite to describe orbiting bodies was the German astronomer Johannes Kepler in his pamphlet Narratio de Observatis a se quatuor Iouis satellitibus erronibus in 1610. He derived the term from the Latin word satelles, meaning guard, attendant, or companion, the term satellite thus became the normal one for referring to an object orbiting a planet, as it avoided the ambiguity of moon. In 1957, however, the launching of the artificial object Sputnik created a need for new terminology, to further avoid ambiguity, the convention is to capitalize the word Moon when referring to Earths natural satellite, but not when referring to other natural satellites. A few recent authors define moon as a satellite of a planet or minor planet, there is no established lower limit on what is considered a moon. Small asteroid moons, such as Dactyl, have also been called moonlets, the upper limit is also vague. Two orbiting bodies are described as a double body rather than primary. Asteroids such as 90 Antiope are considered double asteroids, but they have not forced a clear definition of what constitutes a moon, some authors consider the Pluto–Charon system to be a double planet. In contrast, irregular satellites are thought to be captured asteroids possibly further fragmented by collisions, most of the major natural satellites of the Solar System have regular orbits, while most of the small natural satellites have irregular orbits. The Moon and possibly Charon are exceptions among large bodies in that they are thought to have originated by the collision of two large proto-planetary objects. The material that would have placed in orbit around the central body is predicted to have reaccreted to form one or more orbiting natural satellites. As opposed to planetary-sized bodies, asteroid moons are thought to form by this process. Triton is another exception, although large and in a close, circular orbit, its motion is retrograde, most regular moons in the Solar System are tidally locked to their respective primaries, meaning that the same side of the natural satellite always faces its planet. The only known exception is Saturns natural satellite Hyperion, which rotates chaotically because of the influence of Titan
2.
Uranus
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Uranus is the seventh planet from the Sun. It has the third-largest planetary radius and fourth-largest planetary mass in the Solar System, Uranus is similar in composition to Neptune, and both have different bulk chemical composition from that of the larger gas giants Jupiter and Saturn. For this reason, scientists often classify Uranus and Neptune as ice giants to distinguish them from the gas giants, the interior of Uranus is mainly composed of ices and rock. Uranus is the planet whose name is derived from a figure from Greek mythology. Like the other giant planets, Uranus has a system, a magnetosphere. The Uranian system has a unique configuration among those of the planets because its axis of rotation is tilted sideways and its north and south poles, therefore, lie where most other planets have their equators. In 1986, images from Voyager 2 showed Uranus as an almost featureless planet in visible light, observations from Earth have shown seasonal change and increased weather activity as Uranus approached its equinox in 2007. Wind speeds can reach 250 metres per second, like the classical planets, Uranus is visible to the naked eye, but it was never recognised as a planet by ancient observers because of its dimness and slow orbit. Uranus had been observed on many occasions before its recognition as a planet, possibly the earliest known observation was by Hipparchos, who in 128 BCE might have recorded it as a star for his star catalogue that was later incorporated into Ptolemys Almagest. The earliest definite sighting was in 1690 when John Flamsteed observed it at least six times, the French astronomer Pierre Lemonnier observed Uranus at least twelve times between 1750 and 1769, including on four consecutive nights. Sir William Herschel observed Uranus on March 13,1781 from the garden of his house at 19 New King Street in Bath, Somerset, England, Herschel engaged in a series of observations on the parallax of the fixed stars, using a telescope of his own design. Herschel recorded in his journal, In the quartile near ζ Tauri, either Nebulous star or perhaps a comet. On March 17 he noted, I looked for the Comet or Nebulous Star and found that it is a Comet, the sequel has shown that my surmises were well-founded, this proving to be the Comet we have lately observed. Herschel notified the Astronomer Royal, Nevil Maskelyne, of his discovery and received this flummoxed reply from him on April 23,1781, I dont know what to call it. It is as likely to be a planet moving in an orbit nearly circular to the sun as a Comet moving in a very eccentric ellipsis. I have not yet seen any coma or tail to it, although Herschel continued to describe his new object as a comet, other astronomers had already begun to suspect otherwise. Finnish-Swedish astronomer Anders Johan Lexell, working in Russia, was the first to compute the orbit of the new object and its nearly circular orbit led him to a conclusion that it was a planet rather than a comet. Berlin astronomer Johann Elert Bode described Herschels discovery as a star that can be deemed a hitherto unknown planet-like object circulating beyond the orbit of Saturn
3.
Mass
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In physics, mass is a property of a physical body. It is the measure of a resistance to acceleration when a net force is applied. It also determines the strength of its gravitational attraction to other bodies. The basic SI unit of mass is the kilogram, Mass is not the same as weight, even though mass is often determined by measuring the objects weight using a spring scale, rather than comparing it directly with known masses. An object on the Moon would weigh less than it does on Earth because of the lower gravity and this is because weight is a force, while mass is the property that determines the strength of this force. In Newtonian physics, mass can be generalized as the amount of matter in an object, however, at very high speeds, special relativity postulates that energy is an additional source of mass. Thus, any body having mass has an equivalent amount of energy. In addition, matter is a defined term in science. There are several distinct phenomena which can be used to measure mass, active gravitational mass measures the gravitational force exerted by an object. Passive gravitational mass measures the force exerted on an object in a known gravitational field. The mass of an object determines its acceleration in the presence of an applied force, according to Newtons second law of motion, if a body of fixed mass m is subjected to a single force F, its acceleration a is given by F/m. A bodys mass also determines the degree to which it generates or is affected by a gravitational field and this is sometimes referred to as gravitational mass. The standard International System of Units unit of mass is the kilogram, the kilogram is 1000 grams, first defined in 1795 as one cubic decimeter of water at the melting point of ice. Then in 1889, the kilogram was redefined as the mass of the prototype kilogram. As of January 2013, there are proposals for redefining the kilogram yet again. In this context, the mass has units of eV/c2, the electronvolt and its multiples, such as the MeV, are commonly used in particle physics. The atomic mass unit is 1/12 of the mass of a carbon-12 atom, the atomic mass unit is convenient for expressing the masses of atoms and molecules. Outside the SI system, other units of mass include, the slug is an Imperial unit of mass, the pound is a unit of both mass and force, used mainly in the United States
4.
Kilogram
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The kilogram or kilogramme is the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype of the Kilogram. The avoirdupois pound, used in both the imperial and US customary systems, is defined as exactly 0.45359237 kg, making one kilogram approximately equal to 2.2046 avoirdupois pounds. Other traditional units of weight and mass around the world are also defined in terms of the kilogram, the gram, 1/1000 of a kilogram, was provisionally defined in 1795 as the mass of one cubic centimeter of water at the melting point of ice. The final kilogram, manufactured as a prototype in 1799 and from which the IPK was derived in 1875, had an equal to the mass of 1 dm3 of water at its maximum density. The kilogram is the only SI base unit with an SI prefix as part of its name and it is also the only SI unit that is still directly defined by an artifact rather than a fundamental physical property that can be reproduced in different laboratories. Three other base units and 17 derived units in the SI system are defined relative to the kilogram, only 8 other units do not require the kilogram in their definition, temperature, time and frequency, length, and angle. At its 2011 meeting, the CGPM agreed in principle that the kilogram should be redefined in terms of the Planck constant, the decision was originally deferred until 2014, in 2014 it was deferred again until the next meeting. There are currently several different proposals for the redefinition, these are described in the Proposed Future Definitions section below, the International Prototype Kilogram is rarely used or handled. In the decree of 1795, the term gramme thus replaced gravet, the French spelling was adopted in the United Kingdom when the word was used for the first time in English in 1797, with the spelling kilogram being adopted in the United States. In the United Kingdom both spellings are used, with kilogram having become by far the more common, UK law regulating the units to be used when trading by weight or measure does not prevent the use of either spelling. In the 19th century the French word kilo, a shortening of kilogramme, was imported into the English language where it has used to mean both kilogram and kilometer. In 1935 this was adopted by the IEC as the Giorgi system, now known as MKS system. In 1948 the CGPM commissioned the CIPM to make recommendations for a practical system of units of measurement. This led to the launch of SI in 1960 and the subsequent publication of the SI Brochure, the kilogram is a unit of mass, a property which corresponds to the common perception of how heavy an object is. Mass is a property, that is, it is related to the tendency of an object at rest to remain at rest, or if in motion to remain in motion at a constant velocity. Accordingly, for astronauts in microgravity, no effort is required to hold objects off the cabin floor, they are weightless. However, since objects in microgravity still retain their mass and inertia, the ratio of the force of gravity on the two objects, measured by the scale, is equal to the ratio of their masses. On April 7,1795, the gram was decreed in France to be the weight of a volume of pure water equal to the cube of the hundredth part of the metre
5.
Sycorax
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Sycorax /ˈsɪkəræks/ is an unseen character in William Shakespeares play The Tempest. She is a vicious and powerful witch and the mother of Caliban, one of the few inhabitants of the island on which Prospero. According to the backstory provided by the play, Sycorax, while pregnant with Caliban, was banished from her home in Algiers to the island on which the play takes place. Memories of Sycorax, who several years before the main action of the play begins. Relying on his connection to Sycorax, Caliban claims ownership of the island. Prospero constantly reminds Ariel of Sycoraxs cruel treatment in order to maintain the sprites service, scholars generally agree that Sycorax, a foil for Prospero, is closely related to the Medea of Ovids Metamorphoses. Postcolonialist writers and critics see Sycorax as giving voice to peoples, particularly women, in The Tempest, Prospero describes Sycorax as an ancient and foul witch native to Algiers, and banished to the island for practicing sorcery so strong / That could control the Moon. She proceeded to enslave the spirits there, chief among them Ariel, Sycorax birthed Caliban and taught him to worship the demonic god Setebos. She dies long before the arrival of Prospero and his daughter, Caliban grows to hate Prosperos presence and power on the island, claiming that the land belongs to him since it was his mothers before Prospero appeared. Scholars have unearthed very few facts about Shakespeares sources for Sycorax, in fact, other than her connection to the magical sorceresses Medea and Circe of Greek mythology, nothing conclusive has been proposed. Several competing linguistic theories have been put forth, some scholars argue that her name may be a combination of the Greek sus and korax. Another rough translation produces the phrase the Scythian raven, a description of Medea Also, psychorrhax. One critic searched for a connection to Sycoraxs North African heritage, and found a parallel in Shokereth שוקרת, an especially odd and early guess at a meaning by one critic was sic or rex, a Latin homophone alluding to Queen Elizabeths pride. The general idea for Sycoraxs character may have come from the classical literature familiar to many in Shakespeares day, Sycorax is similar to Medea, a witch in Ovids Metamorphoses, in that both are powerful, magical female figures. Scholars have also pointed out that Sycorax resembles the magical Circe from Greek mythology as well as perhaps a version of Circe found in the mythology of the Coraxi tribe in modern-day Georgia, Sycorax also draws on contemporary beliefs regarding witches. For example, she may embody the belief that all witches have blue eyes, the character may even be a reference to a specific historical personage. Sycoraxs silent role plays an important part in postcolonial interpretations of The Tempest, because she is native to Algiers and her story is only heard through others, she is championed by some scholars as a representation of the silenced African woman. Postcolonial authors have claimed her, for example, Kamau Brathwaite, in his 1994 work Barabajan Poems
6.
William Shakespeare
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William Shakespeare was an English poet, playwright, and actor, widely regarded as the greatest writer in the English language and the worlds pre-eminent dramatist. He is often called Englands national poet, and the Bard of Avon and his extant works, including collaborations, consist of approximately 38 plays,154 sonnets, two long narrative poems, and a few other verses, some of uncertain authorship. His plays have been translated into every major living language and are performed more often than those of any other playwright, Shakespeare was born and brought up in Stratford-upon-Avon, Warwickshire. At the age of 18, he married Anne Hathaway, with whom he had three children, Susanna, and twins Hamnet and Judith. Sometime between 1585 and 1592, he began a career in London as an actor, writer. He appears to have retired to Stratford around 1613, at age 49, Shakespeare produced most of his known work between 1589 and 1613. His early plays were primarily comedies and histories, which are regarded as some of the best work ever produced in these genres. He then wrote mainly tragedies until about 1608, including Hamlet, Othello, King Lear, in his last phase, he wrote tragicomedies, also known as romances, and collaborated with other playwrights. Many of his plays were published in editions of varying quality and it was prefaced with a poem by Ben Jonson, in which Shakespeare is hailed, presciently, as not of an age, but for all time. In the 20th and 21st centuries, his works have been adapted and rediscovered by new movements in scholarship. His plays remain highly popular and are studied, performed. William Shakespeare was the son of John Shakespeare, an alderman and a successful glover originally from Snitterfield, and Mary Arden and he was born in Stratford-upon-Avon and baptised there on 26 April 1564. His actual date of birth unknown, but is traditionally observed on 23 April. This date, which can be traced back to an 18th-century scholars mistake, has proved appealing to biographers because Shakespeare died on 23 April 1616 and he was the third child of eight and the eldest surviving son. At the age of 18, Shakespeare married 26-year-old Anne Hathaway, the consistory court of the Diocese of Worcester issued a marriage licence on 27 November 1582. The next day, two of Hathaways neighbours posted bonds guaranteeing that no lawful claims impeded the marriage, twins, son Hamnet and daughter Judith, followed almost two years later and were baptised 2 February 1585. Hamnet died of unknown causes at the age of 11 and was buried 11 August 1596, after the birth of the twins, Shakespeare left few historical traces until he is mentioned as part of the London theatre scene in 1592. The exception is the appearance of his name in the bill of a law case before the Queens Bench court at Westminster dated Michaelmas Term 1588 and 9 October 1589
. Bibcode:2004ApJ...613L..77G. doi:10.1086/424997.
