Massachusetts the Commonwealth of Massachusetts, is the most populous state in the New England region of the northeastern United States. It borders on the Atlantic Ocean to the east, the states of Connecticut and Rhode Island to the south, New Hampshire and Vermont to the north, New York to the west; the state is named after the Massachusett tribe, which once inhabited the east side of the area, is one of the original thirteen states. The capital of Massachusetts is Boston, the most populous city in New England. Over 80% of Massachusetts's population lives in the Greater Boston metropolitan area, a region influential upon American history and industry. Dependent on agriculture and trade, Massachusetts was transformed into a manufacturing center during the Industrial Revolution. During the 20th century, Massachusetts's economy shifted from manufacturing to services. Modern Massachusetts is a global leader in biotechnology, higher education and maritime trade. Plymouth was the site of the second colony in New England after Popham Colony in 1607 in what is now Maine.
Plymouth was founded in 1620 by passengers of the Mayflower. In 1692, the town of Salem and surrounding areas experienced one of America's most infamous cases of mass hysteria, the Salem witch trials. In 1777, General Henry Knox founded the Springfield Armory, which during the Industrial Revolution catalyzed numerous important technological advances, including interchangeable parts. In 1786, Shays' Rebellion, a populist revolt led by disaffected American Revolutionary War veterans, influenced the United States Constitutional Convention. In the 18th century, the Protestant First Great Awakening, which swept the Atlantic World, originated from the pulpit of Northampton preacher Jonathan Edwards. In the late 18th century, Boston became known as the "Cradle of Liberty" for the agitation there that led to the American Revolution; the entire Commonwealth of Massachusetts has played a powerful commercial and cultural role in the history of the United States. Before the American Civil War, Massachusetts was a center for the abolitionist and transcendentalist movements.
In the late 19th century, the sports of basketball and volleyball were invented in the western Massachusetts cities of Springfield and Holyoke, respectively. In 2004, Massachusetts became the first U. S. state to recognize same-sex marriage as a result of the decision in Goodridge v. Department of Public Health by the Massachusetts Supreme Judicial Court. Many prominent American political dynasties have hailed from the state, including the Adams and Kennedy families. Harvard University in Cambridge is the oldest institution of higher learning in the United States, with the largest financial endowment of any university, Harvard Law School has educated a contemporaneous majority of Justices of the Supreme Court of the United States. Kendall Square in Cambridge has been called "the most innovative square mile on the planet", in reference to the high concentration of entrepreneurial start-ups and quality of innovation which have emerged in the vicinity of the square since 2010. Both Harvard University and the Massachusetts Institute of Technology in Cambridge, have been ranked among the most regarded academic institutions in the world.
Massachusetts' public-school students place among the top tier in the world in academic performance, the state has been ranked as one of the top states in the United States for citizens to live in, as well as one of the most expensive. The Massachusetts Bay Colony was named after the indigenous population, the Massachusett derived from a Wôpanâak word muswach8sut, segmented as mus "big" + wach8 "mountain" + -s "diminutive" + -ut "locative", it has been translated as "near the great hill", "by the blue hills", "at the little big hill", or "at the range of hills", referring to the Blue Hills, or in particular the Great Blue Hill, located on the boundary of Milton and Canton. Alternatively, Massachusett has been represented as Moswetuset—from the name of the Moswetuset Hummock in Quincy, where Plymouth Colony commander Myles Standish, hired English military officer, Squanto, part of the now disappeared Patuxet band of the Wampanoag peoples, met Chief Chickatawbut in 1621; the official name of the state is the "Commonwealth of Massachusetts".
While this designation is part of the state's official name, it has no practical implications. Massachusetts has powers within the United States as other states, it may have been chosen by John Adams for the second draft of the Massachusetts Constitution because unlike the word "state", "commonwealth" at the time had the connotation of a republic, in contrast to the monarchy the former American colonies were fighting against. Massachusetts was inhabited by tribes of the Algonquian language family such as the Wampanoag, Nipmuc, Pocomtuc and Massachusett. While cultivation of crops like squash and corn supplemented their diets, these tribes were dependent on hunting and fishing for most of their food. Villages consisted of lodges called wigwams as well as longhouses, tribes were led by male or female elders known as sachems. In the early 1600s, after contact had been made with Europeans, large numbers of the indigenous peoples in the northeast of what is now the United States were killed by virgin soil epidemics such as smallpox, measles and leptospirosis.
Between 1617 and 1619, smallpox killed ap
Clark University is a private research university in Worcester, Massachusetts. Founded in 1887 with a large endowment from its namesake Jonas Gilman Clark, a prominent businessman, Clark was one of the first modern research universities in the United States. An all-graduate institution, Clark's first undergraduates entered in 1902; the university now offers 46 majors and concentrations in the humanities, social sciences, natural sciences, engineering and allows students to design specialized majors and engage in pre-professional programs. It is noted for its programs in the fields of psychology, physics and entrepreneurship and is a member of the Higher Education Consortium of Central Massachusetts which enables students to cross-register to attend courses at other area institutions including Worcester Polytechnic Institute and the College of the Holy Cross; as a liberal arts–based research university, Clark makes substantial research opportunities available to its students, notably at the undergraduate level through LEEP project funding, yet is respected for its intimate environment as the second smallest university counted among the top 66 national universities by U.
S. News & World Report and as one of 40 Colleges That Change Lives. Graduate and professional programs are offered through the Graduate School, the Graduate School of Management, the Graduate School of Geography, the Frances L. Hiatt School of Psychology, the Gustaf H. Carlson School of Chemistry, the Adam Institute for Urban Teaching and School Practice, the International Development and Environment, the School of Professional Studies; the university competes intercollegiately in 17 NCAA Division III varsity sports as the Clark Cougars and is a part of the New England Women's and Men's Athletic Conference. Intramural and club sports are offered in a wide range of activities. Clark faculty and alumni have founded numerous companies and organizations including Panera Bread, the American Psychological Association, the American Physical Society, have played leading roles in the development of modern rocketry, the wind chill factor, the birth control pill; the university is the alma mater of at least three living billionaires, in addition to its alumni having won three Pulitzer Prizes and an Emmy Award.
On January 17, 1887, successful American businessman Jonas Gilman Clark announced his intention to found and endow a university in the city of Worcester, filing a petition in the Massachusetts Legislature requesting a charter for Clark University. An Act of Incorporation was duly enacted by the legislature and signed by the governor on March 31 of that same year. Clark, a friend of Leland Stanford, was inspired by the plans for Stanford University and founded the University with an endowment of one million dollars, added another million dollars because he feared the university might someday face a lack of funds. Opening on October 2, 1889, Clark was the first all-graduate university in the United States, with departments in mathematics, chemistry and psychology. G. Stanley Hall was appointed the first president of Clark University in 1888, he had been a professor of psychology and pedagogy at Johns Hopkins University, founded just a few years prior and was becoming a model of the modern research university.
Hall spent seven months in Europe recruiting faculty. He became the founder of the American Psychological Association and earned the first Ph. D. in psychology in the United States at Harvard. Clark has played a prominent role in the development of psychology as a distinguished discipline in the United States since. Franz Boas, founder of American cultural anthropology and adviser for the first Ph. D. in anthropology, granted at Clark in 1894, taught at Clark from 1888 until 1892 when he resigned in a dispute with President Hall over academic freedom and joined the faculty of Columbia University. Albert A. Michelson, the first American to receive a Nobel Prize in Physics, best known for his involvement in the Michelson–Morley experiment, which measured the speed of light, was a professor from 1889 to 1892 before becoming head of the physics department at the University of Chicago. Jonas G. Clark died in 1900, leaving gifts to the University and campus library, but reserving half of his estate for the foundation of an undergraduate college.
This had been opposed by President Hall in years past but Clark College opened in 1902, managed independently of Clark University. Clark College and Clark University had different presidents until Hall's retirement in 1920. Clark University began admitting women after Clark's death, the first female Ph. D. in psychology was awarded in 1908. Early Ph. D. students in psychology were ethnically diverse, with several early graduates being Japanese. In 1920, Francis Sumner became the first African American to earn a Ph. D. in psychology. Clark University, along with Stanford and Johns Hopkins, was one of the fourteen founding members of the Association of American Universities, an organization of universities with the most prestigious profiles in research and graduate education, was one of only three New England universities, along with Harvard and Yale, to be a founding member. Clark withdrew its membership in 1999. In order to celebrate the 20th anniversary of Clark's opening, President Hall invited a number of leading thinkers to the University.
Among them was Sigmund Freud who, accompanied by Carl Jung, delivered his five famous "Clark Lectures" there over the course of five days in September 1909, introducing psychoanalysis to an American audience. This was Freud's only visit to the United States. In the 1920s Robert Goddard, a pioneer of rock
Mariner 4 was the fourth in a series of spacecraft intended for planetary exploration in a flyby mode. It was designed to conduct closeup scientific observations of Mars and to transmit these observations to Earth. Launched on November 28, 1964, Mariner 4 performed the first successful flyby of the planet Mars, returning the first close-up pictures of the Martian surface, it captured the first images of another planet returned from deep space. Other mission objectives were to perform field and particle measurements in interplanetary space in the vicinity of Mars and to provide experience in and knowledge of the engineering capabilities for interplanetary flights of long duration. On December 21, 1967 communications with Mariner 4 were terminated; the Mariner 4 spacecraft consisted of an octagonal magnesium frame, 127 cm across a diagonal and 45.7 cm high. Four solar panels were attached to the top of the frame with an end-to-end span of 6.88 meters, including solar pressure vanes which extended from the ends.
A 116.8 cm diameter high-gain parabolic antenna was mounted at the top of the frame as well. An omnidirectional low-gain antenna was mounted on a seven-foot, four inch tall mast next to the high-gain antenna; the overall height of the spacecraft was 2.89 meters. The octagonal frame housed the electronic equipment, midcourse propulsion system, attitude control gas supplies and regulators; the scientific instruments included: A helium magnetometer, mounted on the waveguide leading to the omnidirectional antenna, to measure the magnitude and other characteristics of the interplanetary and planetary magnetic fields. An ionization chamber/Geiger counter, mounted on the waveguide leading to the omnidirectional antenna nearer the body of the spacecraft, to measure the charged-particle intensity and distribution in interplanetary space and in the vicinity of Mars. A trapped radiation detector, mounted on the body with counter-axes pointing 70° and 135° from the solar direction, to measure the intensity and direction of low-energy particles.
A cosmic ray telescope, mounted inside the body pointing in anti-solar direction, to measure the direction and energy spectrum of protons and alpha particles. A solar plasma probe, mounted on the body pointing 10° from the solar direction, to measure the low energy charged particle flux from the Sun. A cosmic dust detector, mounted on the body with microphone plate perpendicular to the plane of orbit, to measure the momentum, distribution and direction of cosmic dust. A television camera, mounted on a scan platform at the bottom center of the spacecraft, to obtain closeup pictures of the surface of Mars; this subsystem consisted of 4 parts, a Cassegrain telescope with a 1.05° by 1.05° field of view, a shutter and red/green filter assembly with 0.08s and 0.20s exposure times, a slow scan vidicon tube which translated the optical image into an electrical video signal, the electronic systems required to convert the analogue signal into a digital bitstream for transmission. The electric power for the instruments and the radio transmitter of Mariner 4 was supplied by 28,224 solar cells contained in the four 176 x 90 cm solar panels, which could provide 310 watts at the distance of Mars.
A rechargeable 1200 W·h silver-zinc battery was used for maneuvers and backup. Monopropellant hydrazine was used for propulsion, via a four-jet vane vector control motor, with 222-newton thrust, installed on one of the sides of the octagonal structure; the space probe's attitude control was provided by 12 cold nitrogen gas jets mounted on the ends of the solar panels and three gyros. Solar pressure vanes, each with an area of 0.65 square meter, were attached to the tips of the solar panels. Positional information was provided by four Sun sensors, a sensor for either the Earth, Mars, or the star Canopus, depending on the time in its spaceflight. Mariner 4 was the first space probe that needed a star for a navigational reference object, since earlier missions, which remained near either the Earth, the Moon, or the planet Venus, had sighted onto either the bright face of the home planet or the brightly lit target. During this flight, both the Earth and Mars would be too dim to lock onto. Another bright source at a wide angle away from the Sun was needed and Canopus filled this requirement.
Subsequently, Canopus was used as a reference point in many following missions. The telecommunications equipment on Mariner 4 consisted of dual S-band transmitters and a single radio receiver which together could send and receive data via the low- and high-gain antennas at 8⅓ or 33⅓ bits per second. Data could be stored onto a magnetic tape recorder with a capacity of 5.24 million bits for transmission. All electronic operations were controlled by a command subsystem which could process any of 29 direct command words or three quantitative word commands for mid-course maneuvers; the central computer and sequencer operated stored time-sequence commands using a 38.4 kHz synchronization frequency as a time reference. Temperature control was achieved through the use of adjustable louvers mounted on six of the electronics assemblies, plus multilayer insulating blankets, polished aluminum shields, surface treatments. Other measurements that could be made included: Radio occultation Celestial mechanics based on precision tracking After Mariner 3 was a total loss due to failure of the payload shroud to jettison, JPL engineers suggested that there had been a malfunction caused during separation of the metal fairing exterior from the fiber
Société astronomique de France
The Société astronomique de France, the French astronomical society, is a non-profit association in the public interest organized under French law. Founded by astronomer Camille Flammarion in 1887, its purpose is to promote the development and practice of astronomy. SAF was established by Camille Flammarion and a group of 11 persons on 28 January 1887 in Flammarion's apartment at 16 rue Cassini, 75014 Paris, close to the Paris Observatory. Open to all, SAF includes both professional and amateur astronomers as members, from France and abroad, its objective was defined at the time of its establishment as: "A Society is founded with the aim to bring together people involved or theoretically in Astronomy, or who are interested in the development of this Science and the extension of its influence for the illumination of minds. Its efforts shall support the increase and extension of this Science, as well as to facilitating ways and means for those who wish to undertake astronomical studies. All friends of the Science and Progress are invited for its composition and development."On 4 April 1887, the headquarters was established at the Hôtel des Sociétés Savantes, 28 rue Serpente, in the 6th arrondissement of Paris.
The society built an observatory on the top floor of the building for its members use that operated from 1890–1968. On 17 October 1966, the headquarters moved to the Maison de la Chimie at 28 rue Saint-Dominique, Paris 75007. Since 1974, the headquarters has been located at 3, rue Beethoven, Paris 75016. To date, the Society has had 49 presidents comprising many illustrious persons in astronomy and related fields. By profession, half of the presidents were astronomers, followed by physicists, other professions that includes engineers, a medical doctor, two generals, a prince, a writer, an historian. Monthly magazine L'Astronomie and the periodical Observations et Travaux dedicated to the techniques applied by its members and the results they obtained. Specialized commissions for Comets, Double stars, Instruments, Meteors and impacts, Night skies, Planetary observations, Radioastronomy and the Sun. Monthly conferences, initiation courses in astronomy, regular meetings of the commissions; the monthly conferences are convened in the lecture hall of Télécom ParisTech, the other events are held at SAF headquarters in the 16th arrondissement of Paris.
Rencontres AstroCiel, an annual astronomical gathering every August at which astronomy enthusiasts come together for two weeks of nighttime observations in Valdrôme in southeastern France, at 1,400 meters altitude. An extensive library that includes both historical and modern works, available for research and consultation to members and non-members. Two astronomical observatories, where it offers the public the opportunity to explore the night sky: the Astronomy Tower of the Sorbonne in the 5th arrondissement of Paris, the Camille Flammarion Observatory in Juvisy-sur-Orge; the society has offered the following awards over the years to its members and to notable personalities in the field of astronomy in France and abroad. Not all awards are given every year, some have been discontinued. Prix Jules Janssen. Recognition of astronomical work in general. Prize established by Jules Janssen. Annual prize awarded 1896–present. Prix des Dames. Recognition of services rendered to the Society of any kind.
Prize established at the initiative of Sylvie Camille Flammarion and a group of women members of SAF. Annual prize awarded 1896–present. Prix Maurice Ballot. Recognition of authors of works of the Society's observatory. Biannual prize established by a donation of SAF Librarian. Awarded when merited. Given 1921–present. Prix Georges Bidault de l'Isle. Encouragement of young people who show a special talent for astronomy or meteorology. Individuals are chosen from participants at courses and conferences, collaboration at the Observatory, or through communications in the bulletin during the preceding year. Prior to 1956, this award was known as the Prix de l'Observatoire de la Guette.. Annual prize awarded 1925– Prix Henry Rey. Recognition of an important work in astronomy. A silver medal is awarded annually. Established by funds bequeathed by Henry Rey of Marseille. Annual prize awarded 1926–present. Prix Gabrielle et Camille Flammarion. Recognition of an important discovery and marked progress in astronomy or in a sister science, to aid an independent researcher, or to assist a young researcher to begin work in astronomy.
Given odd-numbered years, alternating with the Prix Dorothea Klumpke-Isaac Roberts. Prize awarded 1930–present. Prix Dorothea Klumpke - Isaac Roberts. Encouragement of the study of the wide and diffuse nebulae of William Herschel, the obscure objects of Barnard, or the cosmic clouds of R. P. Hagen. Biannual prize established by a donation of Dorothea Klumpke Roberts in honor of her late husband Isaac Roberts. Prize awarded 1931– Prix Marcel Moye. Recognition of a young member of the Society for his or her observations. Individuals must be 25 years of less. Annual prize awarded 1946–. Prix Marius Jacquemetton. Recognition of a work or research by a member of the Society, a student, or a young astronomer. Annual prize awarded 1947–present. Prix Viennet - Damien. Recognition of a beautiful piece of optics or for some work in this branch of astronomy. Given in alternate years with the Prix Dorothea Klumpke-Isaac Roberts. Prize awarded 1949– Prix Julien Saget. Recognition of an amateur for his or her remarkable astronomical photography.
Annual prize awarded 1969–present. Prix Edmond Gir
Harvard University is a private Ivy League research university in Cambridge, with about 6,700 undergraduate students and about 15,250 postgraduate students. Established in 1636 and named for its first benefactor, clergyman John Harvard, Harvard is the United States' oldest institution of higher learning, its history and wealth have made it one of the world's most prestigious universities; the Harvard Corporation is its first chartered corporation. Although never formally affiliated with any denomination, the early College trained Congregational and Unitarian clergy, its curriculum and student body were secularized during the 18th century, by the 19th century, Harvard had emerged as the central cultural establishment among Boston elites. Following the American Civil War, President Charles W. Eliot's long tenure transformed the college and affiliated professional schools into a modern research university. A. Lawrence Lowell, who followed Eliot, further reformed the undergraduate curriculum and undertook aggressive expansion of Harvard's land holdings and physical plant.
James Bryant Conant led the university through the Great Depression and World War II and began to reform the curriculum and liberalize admissions after the war. The undergraduate college became coeducational after its 1977 merger with Radcliffe College; the university is organized into eleven separate academic units—ten faculties and the Radcliffe Institute for Advanced Study—with campuses throughout the Boston metropolitan area: its 209-acre main campus is centered on Harvard Yard in Cambridge 3 miles northwest of Boston. Harvard's endowment is worth $39.2 billion, making it the largest of any academic institution. Harvard is a large residential research university; the nominal cost of attendance is high, but the university's large endowment allows it to offer generous financial aid packages. The Harvard Library is the world's largest academic and private library system, comprising 79 individual libraries holding over 18 million items; the University is cited as one of the world's top tertiary institutions by various organizations.
Harvard's alumni include eight U. S. presidents, more than thirty foreign heads of state, 62 living billionaires, 359 Rhodes Scholars, 242 Marshall Scholars. As of October 2018, 158 Nobel laureates, 18 Fields Medalists, 14 Turing Award winners have been affiliated as students, faculty, or researchers. In addition, Harvard students and alumni have won 10 Academy Awards, 48 Pulitzer Prizes and 108 Olympic medals, have founded a large number of companies worldwide. Harvard was established in 1636 by vote of the Great and General Court of the Massachusetts Bay Colony. In 1638, it acquired British North America's first known printing press. In 1639, it was named Harvard College after deceased clergyman John Harvard, an alumnus of the University of Cambridge, who had left the school £779 and his scholar's library of some 400 volumes; the charter creating the Harvard Corporation was granted in 1650. A 1643 publication gave the school's purpose as "to advance learning and perpetuate it to posterity, dreading to leave an illiterate ministry to the churches when our present ministers shall lie in the dust".
It offered a classic curriculum on the English university model—many leaders in the colony had attended the University of Cambridge—but conformed to the tenets of Puritanism. It was never affiliated with any particular denomination, but many of its earliest graduates went on to become clergymen in Congregational and Unitarian churches; the leading Boston divine Increase Mather served as president from 1685 to 1701. In 1708, John Leverett became the first president, not a clergyman, marking a turning of the college from Puritanism and toward intellectual independence. Throughout the 18th century, Enlightenment ideas of the power of reason and free will became widespread among Congregational ministers, putting those ministers and their congregations in tension with more traditionalist, Calvinist parties; when the Hollis Professor of Divinity David Tappan died in 1803 and the president of Harvard Joseph Willard died a year in 1804, a struggle broke out over their replacements. Henry Ware was elected to the chair in 1805, the liberal Samuel Webber was appointed to the presidency of Harvard two years which signaled the changing of the tide from the dominance of traditional ideas at Harvard to the dominance of liberal, Arminian ideas.
In 1846, the natural history lectures of Louis Agassiz were acclaimed both in New York and on the campus at Harvard College. Agassiz's approach was distinctly idealist and posited Americans' "participation in the Divine Nature" and the possibility of understanding "intellectual existences". Agassiz's perspective on science combined observation with intuition and the assumption that a person can grasp the "divine plan" in all phenomena; when it came to explaining life-forms, Agassiz resorted to matters of shape based on a presumed archetype for his evidence. This dual view of knowledge was in concert with the teachings of Common Sense Realism derived from Scottish philosophers Thomas Reid and Dugald Stewart, whose works were part of the Harvard curriculum at the time; the popularity of Agassiz's efforts to "soar with Plato" also derived from other writings to which Harvard students
Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System after Mercury. In English, Mars carries a name of the Roman god of war, is referred to as the "Red Planet" because the reddish iron oxide prevalent on its surface gives it a reddish appearance, distinctive among the astronomical bodies visible to the naked eye. Mars is a terrestrial planet with a thin atmosphere, having surface features reminiscent both of the impact craters of the Moon and the valleys and polar ice caps of Earth; the days and seasons are comparable to those of Earth, because the rotational period as well as the tilt of the rotational axis relative to the ecliptic plane are similar. Mars is the site of Olympus Mons, the largest volcano and second-highest known mountain in the Solar System, of Valles Marineris, one of the largest canyons in the Solar System; the smooth Borealis basin in the northern hemisphere covers 40% of the planet and may be a giant impact feature. Mars has two moons and Deimos, which are small and irregularly shaped.
These may be captured asteroids, similar to a Mars trojan. There are ongoing investigations assessing the past habitability potential of Mars, as well as the possibility of extant life. Future astrobiology missions are planned, including the Mars 2020 and ExoMars rovers. Liquid water cannot exist on the surface of Mars due to low atmospheric pressure, less than 1% of the Earth's, except at the lowest elevations for short periods; the two polar ice caps appear to be made of water. The volume of water ice in the south polar ice cap, if melted, would be sufficient to cover the entire planetary surface to a depth of 11 meters. In November 2016, NASA reported finding a large amount of underground ice in the Utopia Planitia region of Mars; the volume of water detected has been estimated to be equivalent to the volume of water in Lake Superior. Mars can be seen from Earth with the naked eye, as can its reddish coloring, its apparent magnitude reaches −2.94, surpassed only by Jupiter, the Moon, the Sun.
Optical ground-based telescopes are limited to resolving features about 300 kilometers across when Earth and Mars are closest because of Earth's atmosphere. Mars is half the diameter of Earth with a surface area only less than the total area of Earth's dry land. Mars is less dense than Earth, having about 15% of Earth's volume and 11% of Earth's mass, resulting in about 38% of Earth's surface gravity; the red-orange appearance of the Martian surface is caused by rust. It can look like butterscotch. Like Earth, Mars has differentiated into a dense metallic core overlaid by less dense materials. Current models of its interior imply a core with a radius of about 1,794 ± 65 kilometers, consisting of iron and nickel with about 16–17% sulfur; this iron sulfide core is thought to be twice as rich in lighter elements as Earth's. The core is surrounded by a silicate mantle that formed many of the tectonic and volcanic features on the planet, but it appears to be dormant. Besides silicon and oxygen, the most abundant elements in the Martian crust are iron, aluminum and potassium.
The average thickness of the planet's crust is about 50 km, with a maximum thickness of 125 km. Earth's crust averages 40 km. Mars is a terrestrial planet that consists of minerals containing silicon and oxygen and other elements that make up rock; the surface of Mars is composed of tholeiitic basalt, although parts are more silica-rich than typical basalt and may be similar to andesitic rocks on Earth or silica glass. Regions of low albedo suggest concentrations of plagioclase feldspar, with northern low albedo regions displaying higher than normal concentrations of sheet silicates and high-silicon glass. Parts of the southern highlands include detectable amounts of high-calcium pyroxenes. Localized concentrations of hematite and olivine have been found. Much of the surface is covered by finely grained iron oxide dust. Although Mars has no evidence of a structured global magnetic field, observations show that parts of the planet's crust have been magnetized, suggesting that alternating polarity reversals of its dipole field have occurred in the past.
This paleomagnetism of magnetically susceptible minerals is similar to the alternating bands found on Earth's ocean floors. One theory, published in 1999 and re-examined in October 2005, is that these bands suggest plate tectonic activity on Mars four billion years ago, before the planetary dynamo ceased to function and the planet's magnetic field faded, it is thought that, during the Solar System's formation, Mars was created as the result of a stochastic process of run-away accretion of material from the protoplanetary disk that orbited the Sun. Mars has many distinctive chemical features caused by its position in the Solar System. Elements with comparatively low boiling points, such as chlorine and sulphur, are much more common on Mars than Earth. After the formation of the planets, all were subjected to the so-called "Late Heavy Bombardment". About 60% of the surface of Mars shows a record of impacts from that era, whereas much of the remaining surface is underlain by immense impact basins caused by those events.
There is evidence of an enormous impact basin in the northern hemisphere of Mars, spanning 10,600 by 8,500 km, or four times the size of the Moon's South Pole – Aitk
Joseon dynasty was a Korean dynastic kingdom that lasted for five centuries. It was founded by Yi Seong-gye in July 1392 and was replaced by the Korean Empire in October 1897, it was founded following the aftermath of the overthrow of Goryeo in what is today the city of Kaesong. Early on, Korea was retitled and the capital was relocated to modern-day Seoul; the kingdom's northernmost borders were expanded to the natural boundaries at the rivers of Amnok and Tuman through the subjugation of the Jurchens. Joseon was the last dynasty of its longest-ruling Confucian dynasty. During its reign, Joseon encouraged the entrenchment of Chinese Confucian ideals and doctrines in Korean society. Neo-Confucianism was installed as the new dynasty's state ideology. Buddhism was accordingly discouraged and faced persecutions by the dynasty. Joseon consolidated its effective rule over the territory of current Korea and saw the height of classical Korean culture, trade and science and technology. However, the dynasty was weakened during the late 16th and early 17th centuries, when the Japanese invasions of Korea in the 1590s and the first and second Manchu invasions nearly overran the Korean Peninsula, leading to an harsh isolationist policy, for which the country became known as the "hermit kingdom" in Western literature.
After the end of invasions from Manchuria, Joseon experienced a nearly 200-year period of peace. However, whatever power the kingdom recovered during its isolation further waned as the 18th century came to a close, faced with internal strife, power struggles, international pressure and rebellions at home, the Joseon dynasty declined in the late 19th century; the Joseon period has left a substantial legacy to modern Korea. By the late 14th century, the nearly 500-year-old Goryeo established in 918 was tottering, its foundations collapsing from years of war and de facto occupation from the disintegrating Mongol Empire. Following the emergence of the Ming dynasty, the royal court in Goryeo split into two conflicting factions: the group led by General Yi and the camp led by General Choe. Goryeo claimed to be the successor of the ancient kingdom of Goguryeo; when a Ming messenger came to Goryeo in 1388, the 14th year of U of Goryeo, to demand that Goguryeo's former northern territory be handed over to Ming China, General Choe seized the chance to argue for an attack on the Liaodong Peninsula.
Yi was chosen to lead the attack. He killed King U and his son after a failed restoration and forcibly placed a royal named Yi on the throne. In 1392, Yi eliminated Jeong Mong-ju respected leader of a group loyal to Goryeo dynasty, dethroned King Gongyang, exiling him to Wonju, before he ascended the throne; the Goryeo Dynasty had come to an end after 500 years of rule. In the beginning of his reign, Yi Seonggye, now ruler of Korea, intended to continue use of the name Goryeo for the country he ruled and change the royal line of descent to his own, thus maintaining the façade of continuing the 500-year-old Goryeo tradition. However, after numerous threats of mutiny from the drastically weakened but still influential Gwonmun nobles, who continued to swear allegiance to the remnants of the Goryeo and now the demoted Wang clan, the consensus in the reformed court was that a new dynastic title was needed to signify the change. In naming the new dynasty, Taejo contemplated two possibilities - "Hwaryeong" and "Joseon".
After much internal deliberation, as well as endorsement by the neighboring Ming dynasty's emperor, Taejo declared the name of the kingdom to be Joseon, a tribute to the ancient Korean state of Gojoseon. He moved the capital to Hanyang from Kaesong; when the new dynasty was promulgated and brought into existence, Taejo brought up the issue of which son would be his successor. Although Yi Bangwon, Taejo's fifth son by Queen Sineui, had contributed most to assisting his father's rise to power, the prime minister Jeong Do-jeon and Nam Eun used their influence on King Taejo to name his eighth son Grand Prince Uian as crown prince in 1392; this conflict arose because Jeong Dojeon, who shaped and laid down ideological and legal foundations of the new dynasty more than anyone else, saw Joseon as a kingdom led by ministers appointed by the king while Yi Bangwon wanted to establish the absolute monarchy ruled directly by the king. With Taejo's support, Jeong Dojeon kept limiting the royal family's power by prohibiting political involvement of princes and attempting to abolish their private armies.
Both sides were getting ready to strike first. After the sudden death of Queen Sindeok, while King Taejo was still in mourning for his second wife, Yi Bangwon struck first by raiding the palace and killed Jeong Dojeon and his supporters as well as Queen Sindeok's two sons including the crown prince in 1398; this incident became known as the First Strife of Princes. Aghast at the fact that his sons were willing to kill each other for the crown, psychologically exhausted from the death of