Project Mercury
Project Mercury was the first human spaceflight program of the United States, running from 1958 through 1963. An early highlight of the Space Race, its goal was to put a man into Earth orbit and return him safely, ideally before the Soviet Union. Taken over from the US Air Force by the newly created civilian space agency NASA, it conducted twenty unmanned developmental flights, six successful flights by astronauts; the program, which took its name from Roman mythology, cost $2.2 billion adjusted for inflation. The astronauts were collectively known as the "Mercury Seven", each spacecraft was given a name ending with a "7" by its pilot; the Space Race began with the 1957 launch of the Soviet satellite Sputnik 1. This came as a shock to the American public, led to the creation of NASA to expedite existing US space exploration efforts, place most of them under civilian control. After the successful launch of the Explorer 1 satellite in 1958, manned spaceflight became the next goal; the Soviet Union put the first human, cosmonaut Yuri Gagarin, into a single orbit aboard Vostok 1 on April 12, 1961.
Shortly after this, on May 5, the US launched its first astronaut, Alan Shepard, on a suborbital flight. Soviet Gherman Titov followed with a day-long orbital flight in August 1961; the US reached its orbital goal on February 20, 1962, when John Glenn made three orbits around the Earth. When Mercury ended in May 1963, both nations had sent six people into space, but the Soviets led the US in total time spent in space; the Mercury space capsule was produced by McDonnell Aircraft, carried supplies of water and oxygen for about one day in a pressurized cabin. Mercury flights were launched from Cape Canaveral Air Force Station in Florida, on launch vehicles modified from the Redstone and Atlas D missiles; the capsule was fitted with a launch escape rocket to carry it safely away from the launch vehicle in case of a failure. The flight was designed to be controlled from the ground via the Manned Space Flight Network, a system of tracking and communications stations. Small retrorockets were used to bring the spacecraft out of its orbit, after which an ablative heat shield protected it from the heat of atmospheric reentry.
A parachute slowed the craft for a water landing. Both astronaut and capsule were recovered by helicopters deployed from a US Navy ship; the Mercury project gained popularity, its missions were followed by millions on radio and TV around the world. Its success laid the groundwork for Project Gemini, which carried two astronauts in each capsule and perfected space docking maneuvers essential for manned lunar landings in the subsequent Apollo program announced a few weeks after the first manned Mercury flight. Project Mercury was approved on October 7, 1958 and publicly announced on December 17. Called Project Astronaut, President Dwight Eisenhower felt that gave too much attention to the pilot. Instead, the name Mercury was chosen from classical mythology, which had lent names to rockets like the Greek Atlas and Roman Jupiter for the SM-65 and PGM-19 missiles, it absorbed military projects with the same aim, such as the Air Force Man in Space Soonest. Following the end of World War II, a nuclear arms race evolved between the Soviet Union.
Since the USSR did not have bases in the western hemisphere from which to deploy bomber planes, Joseph Stalin decided to develop intercontinental ballistic missiles, which drove a missile race. The rocket technology in turn enabled both sides to develop Earth-orbiting satellites for communications, gathering weather data and intelligence. Americans were shocked when the Soviet Union placed the first satellite into orbit in October 1957, leading to a growing fear that the US was falling into a "missile gap". A month the Soviets launched Sputnik 2, carrying a dog into orbit. Though the animal was not recovered alive, it was obvious. Unable to disclose details of military space projects, President Eisenhower ordered the creation of a civilian space agency in charge of civilian and scientific space exploration. Based on the federal research agency National Advisory Committee for Aeronautics, it was named the National Aeronautics and Space Administration, it achieved its first goal, an American satellite in space, in 1958.
The next goal was to put a man there. The limit of space was defined at the time as a minimum altitude of 62 mi, the only way to reach it was by using rocket-powered boosters; this created risks for the pilot, including explosion, high g-forces and vibrations during lift off through a dense atmosphere, temperatures of more than 10,000 °F from air compression during reentry. In space, pilots would require pressurized chambers or space suits to supply fresh air. While there, they would experience weightlessness, which could cause disorientation. Further potential risks included radiation and micrometeoroid strikes, both of which would be absorbed in the atmosphere. All seemed possible to overcome: experience from satellites suggested micrometeoroid risk was negligible, experiments in the early 1950s with simulated weightlessness, high g-forces on humans, sending animals to the limit of space, all suggested potential problems could be overcome by known technologies. Reentry was studied using the nuclear warheads of ballistic missiles, which demonstrated a blunt, forward-facing heat shield could solve the problem of heating.
T. Keith Glennan had been appointed the first Administrator of NASA, with Hugh L. Dryden as his Deputy, at the creation of the agency on October 1, 1958. Glennan would report to the preside
Sam Gilliam
Sam Gilliam is a color field painter and lyrical abstractionist artist. Gilliam, an African American, is associated with the Washington Color School, a group of Washington, D. C. area artists that developed a form of abstract art from color field painting in the 1950s and 1960s. His works have been described as belonging to abstract expressionism and lyrical abstraction, he works on stretched and wrapped canvas, adds sculptural 3D elements. He is recognized as the first artist to introduce the idea of a draped, painted canvas hanging without stretcher bars around 1965; this was a major contribution to the Color Field School. In his more recent work, Gilliam has worked with polypropylene, computer-generated imaging and iridescent acrylics, handmade paper, steel and plastic. Sam Gilliam was born in Tupelo, the seventh of eight children born to Sam and Estery Gilliam; the Gilliams moved to Kentucky shortly after he was born. His father worked on the railroad. At a young age, Gilliam spent most of his time drawing.
In 1951, Gilliam graduated from Central High School in Louisville. After high school, Gilliam attended the University of Louisville and received his B. A. degree in fine art in 1955. In the same year he held his first solo art exhibition at the University. From 1956 to 1958 Gilliam served in the United States Army, he returned to the University of Louisville in 1961 and received his M. A. degree in painting. He has taught at the Corcoran School of Art, the Maryland Institute College of Art and Carnegie Mellon University. Gilliam taught art in public schools. In 1962, Gilliam moved to Washington, D. C. after marrying Washington Post reporter Dorothy Butler, whom he divorced. Gilliam lives in Washington, D. C. with his long-term partner Annie Gawlak. In the 1960s, as the political and social front of America began to explode in all directions, Gilliam began to take bold declarative initiatives, making definitive imagery, inspired by the specific conditions of the African-American experience; this was at a time that "abstract art was said by some to be irrelevant to black African life."
Abstraction remained a critical issue for artists such as Gilliam. His early style developed from brooding figural abstractions into large paintings of flatly applied color, pushing Gilliam to remove the easel by eliminating the stretcher. During this time period, Gilliam painted large color-stained canvases, which he draped and suspended from the walls and ceilings, comprising some of his best-known artwork. In 1972, Gilliam represented the US at the Venice Biennale, the first African-American artist to do so. In 2017, he exhibited at the Venice Biennale once again, in the Giardini's central pavillion. Gilliam was influenced by German Expressionists such as Emil Nolde, Paul Klee, the American Bay Area Figurative School artist Nathan Oliveira. Early influences included Kenneth Noland, he says that he found lots of clues about how to go about his work from Tatlin, Frank Stella, Hans Hofmann, Georges Braque, Pablo Picasso, Paul Cézanne. In 1963, Thomas Downing, an artist who identified himself with the Washington Color School, introduced Gilliam to this new school of thought.
Around 1965, Gilliam became the first painter to introduce the idea of the unsupported canvas. He was inspired to do this by observing laundry hanging outside his Washington studio, his drape paintings were suspended from ceilings or arranged on walls or floors, representing a sculptural third dimension in painting. Gilliam says that his paintings are based on the fact that the framework of the painting is in real space, he is attracted to the way it functions. Gilliam's draped canvases change in each environment where they are arranged and he embellishes the works with metal and wooden beams. In 1975, Gilliam veered away from the draped canvases, became influenced by jazz musicians such as Miles Davis and John Coltrane, he started producing dynamic geometric collages, which he called "Black Paintings" because they are painted in shades of black. In the 1980s Gilliam's style changed once more, transitioning to quilted paintings reminiscent of African patchwork quilts from his childhood, using an improvisational approach.
His most recent works are textured paintings. Gilliam has had many commissions, awards and honorary doctorates. A major retrospective of his work was held at the Corcoran Gallery of Art in 2005, he was named the 2006 University of Louisville Alumnus of the Year. Other honors include eight honorary doctorates, the Kentucky Governor’s Award in the Arts, he has received several several National Endowment for the Arts grants, the Longview Foundation Award, a Guggenheim Fellowship. He received the Art Institute of Chicago’s Norman W. Harris Prize, an Artist’s Fellowship from the Washington Gallery of Modern Art. In 1987 he was selected by the Smithsonian Art Collectors Program to produce a print to celebrate the opening of the S. Dillon Ripley Center in the National Mall, he donated his talent to produce In Celebration, a 35-color limited-edition serigraph that highlighted his trademark use of color. The sale benefited the Smithsonian Associates, the continuing education branch of the larger Smithsonian Institution.
In early 2009, he again donated his talents to the Smithsonian Associates to produce a 90-color serigraph entitled Museum Moment, which he describes as "a celebration of art". In April 2003, a dedication of the installation of his work, Matrix Red-Matrix Blue, was held at Rutgers Law School, Newark. In May 2011, his work From a Model to a Rainbow was installed in the Washington Metro
Concrete
Concrete Portland cement concrete, is a composite material composed of fine and coarse aggregate bonded together with a fluid cement that hardens over time—most a lime-based cement binder, such as Portland cement, but sometimes with other hydraulic cements, such as a calcium aluminate cement. It is distinguished from other, non-cementitious types of concrete all binding some form of aggregate together, including asphalt concrete with a bitumen binder, used for road surfaces, polymer concretes that use polymers as a binder; when aggregate is mixed together with dry Portland cement and water, the mixture forms a fluid slurry, poured and molded into shape. The cement reacts chemically with the water and other ingredients to form a hard matrix that binds the materials together into a durable stone-like material that has many uses. Additives are included in the mixture to improve the physical properties of the wet mix or the finished material. Most concrete is poured with reinforcing materials embedded to provide tensile strength, yielding reinforced concrete.
Famous concrete structures include the Panama Canal and the Roman Pantheon. The earliest large-scale users of concrete technology were the ancient Romans, concrete was used in the Roman Empire; the Colosseum in Rome was built of concrete, the concrete dome of the Pantheon is the world's largest unreinforced concrete dome. Today, large concrete structures are made with reinforced concrete. After the Roman Empire collapsed, use of concrete became rare until the technology was redeveloped in the mid-18th century. Worldwide, concrete has overtaken steel in tonnage of material used; the word concrete comes from the Latin word "concretus", the perfect passive participle of "concrescere", from "con-" and "crescere". Small-scale production of concrete-like materials was pioneered by the Nabatean traders who occupied and controlled a series of oases and developed a small empire in the regions of southern Syria and northern Jordan from the 4th century BC, they discovered the advantages of hydraulic lime, with some self-cementing properties, by 700 BC.
They built kilns to supply mortar for the construction of rubble-wall houses, concrete floors, underground waterproof cisterns. They kept the cisterns secret; some of these structures survive to this day. In the Ancient Egyptian and Roman eras, builders discovered that adding volcanic ash to the mix allowed it to set underwater. German archaeologist Heinrich Schliemann found concrete floors, which were made of lime and pebbles, in the royal palace of Tiryns, which dates to 1400–1200 BC. Lime mortars were used in Greece and Cyprus in 800 BC; the Assyrian Jerwan Aqueduct made use of waterproof concrete. Concrete was used for construction in many ancient structures; the Romans used concrete extensively from 300 BC to a span of more than seven hundred years. During the Roman Empire, Roman concrete was made from quicklime, pozzolana and an aggregate of pumice, its widespread use in many Roman structures, a key event in the history of architecture termed the Roman Architectural Revolution, freed Roman construction from the restrictions of stone and brick materials.
It enabled revolutionary new designs in terms of both structural dimension. Concrete, as the Romans knew it, was a revolutionary material. Laid in the shape of arches and domes, it hardened into a rigid mass, free from many of the internal thrusts and strains that troubled the builders of similar structures in stone or brick. Modern tests show that opus caementicium had as much compressive strength as modern Portland-cement concrete. However, due to the absence of reinforcement, its tensile strength was far lower than modern reinforced concrete, its mode of application was different: Modern structural concrete differs from Roman concrete in two important details. First, its mix consistency is fluid and homogeneous, allowing it to be poured into forms rather than requiring hand-layering together with the placement of aggregate, which, in Roman practice consisted of rubble. Second, integral reinforcing steel gives modern concrete assemblies great strength in tension, whereas Roman concrete could depend only upon the strength of the concrete bonding to resist tension.
The long-term durability of Roman concrete structures has been found to be due to its use of pyroclastic rock and ash, whereby crystallization of strätlingite and the coalescence of calcium–aluminum-silicate–hydrate cementing binder helped give the concrete a greater degree of fracture resistance in seismically active environments. Roman concrete is more resistant to erosion by seawater than modern concrete; the widespread use of concrete in many Roman structures ensured that many survive to the present day. The Baths of Caracalla in Rome are just one example. Many Roman aqueducts and bridges, such as the magnificent Pont du Gard in southern France, have masonry cladding on a concrete core, as does the dome of the Pantheon. After the Roman Empire, the use of burned lime and pozzolana was reduced until the technique was all but forgotten between 500 and the 14th century. From the 14th century to the mid-18th century, the use of cement returned; the Canal du Midi was built using concrete in 1670.
The greatest step forward in the modern use
Slavery in the United States
Slavery in the United States was the legal institution of human chattel enslavement of Africans and African Americans, that existed in the United States of America in the 18th and 19th centuries. Slavery had been practiced in British America from early colonial days, was legal in all Thirteen Colonies at the time of the Declaration of Independence in 1776, it lasted in about half the states until 1865, when it was prohibited nationally by the Thirteenth Amendment. As an economic system, slavery was replaced by sharecropping. By the time of the American Revolution, the status of slave had been institutionalized as a racial caste associated with African ancestry; when the United States Constitution was ratified in 1789, a small number of free people of color were among the voting citizens. During and following the Revolutionary War, abolitionist laws were passed in most Northern states and a movement developed to abolish slavery. Northern states depended on free labor and all had abolished slavery by 1805.
The rapid expansion of the cotton industry in the Deep South after the invention of the cotton gin increased demand for slave labor to pick cotton when it all ripened at once, the Southern states continued as slave societies. Those states attempted to extend slavery into the new Western territories to keep their share of political power in the nation. Southern leaders wanted to annex Cuba as a slave territory; the United States became polarized over the issue of slavery, split into slave and free states, in effect divided by the Mason–Dixon line which delineated Pennsylvania from Maryland and Delaware. During the Jefferson administration, Congress prohibited the importation of slaves, effective 1808, although smuggling via Spanish Florida was not unusual. Domestic slave trading, continued at a rapid pace, driven by labor demands from the development of cotton plantations in the Deep South. More than one million slaves were sold from the Upper South, which had a surplus of labor, taken to the Deep South in a forced migration, splitting up many families.
New communities of African-American culture were developed in the Deep South, the total slave population in the South reached 4 million before liberation. As the West was developed for settlement, the Southern state governments wanted to keep a balance between the number of slave and free states to maintain a political balance of power in Congress; the new territories acquired from Britain and Mexico were the subject of major political compromises. By 1850, the newly rich cotton-growing South was threatening to secede from the Union, tensions continued to rise. Many white Southern Christians, including church ministers, attempted to justify their support for slavery as modified by Christian paternalism; the largest denominations—the Baptist and Presbyterian churches—split over the slavery issue into regional organizations of the North and South. When Abraham Lincoln won the 1860 election on a platform of halting the expansion of slavery, seven states broke away to form the Confederacy; the first six states to secede held the greatest number of slaves in the South.
Shortly after, the Civil War began. Four additional slave states seceded after Lincoln requested arms in order to make a retaliatory strike. Due to Union measures such as the Confiscation Acts and Emancipation Proclamation in 1863, the war ended slavery before ratification of the Thirteenth Amendment in December 1865 formally ended the legal institution throughout the United States. Africans first came to the New World with Christopher Columbus in 1492. Juan Las Canaries was a crewman on the Santa Maria. Not much longer after, the first enslavement occurred in what would be the United States. In 1508, Ponce de Leon established the first settlement near present-day San Juan and began enslaving the indigenous Tainos. In 1513, to supplement the dwindling Tainos population, the first African slaves were imported to Puerto Rico; the first African slaves within the continental United States arrived via Santo Domingo to the San Miguel de Gualdape colony, founded by Spanish explorer Lucas Vázquez de Ayllón in 1526.
The ill-fated colony was immediately disrupted by a fight over leadership, during which the slaves revolted and fled the colony to seek refuge among local Native Americans. De Ayllón and many of the colonists died shortly afterwards of an epidemic and the colony was abandoned; the settlers and the slaves who had not escaped returned to Haiti, whence. On August 28, 1565, St. Augustine, Florida was founded by the Spanish conquistador Don Pedro Menendez de Aviles and he brought three African slaves with him. During the 16th and 17th centuries, St. Augustine was the hub of the slave trade in Spanish colonial Florida and the first permanent settlement in the continental United States to include African slaves.60 years in the early years of the Chesapeake Bay settlements, colonial officials found it difficult to attract and retain laborers under the harsh frontier conditions, there was a high mortality rate. Most laborers came from Britain as indentured laborers, signing contracts of indenture to pay with work for their passage, their upkeep and training on a farm.
The colonies had agricultural economies. These indentured laborers were young people who intended to become permanent residents. In some cases, convicted criminals were transported to the colonies as indentured laborers, rather than being imprisoned; the indentured laborers were not slaves, but were required to work
James E. Mayo
James E. Mayo was an American exhibition specialist, he held this role at the Anacostia Community Museum, where he was co-director. James Mayo was born and raised in Washington, D. C.. After he graduated from Cardozo High School, he joined the workforce, starting his career, in 1959, at the National Museum of American History, he would marry. Upon joining the National Museum of American History, Mayo took on the role of exhibitions production supervisor, he would go on to design exhibitions for Dumbarton Oaks and the City University of New York. He ran the renovation of the Benjamin Brown French School and was chairman of the board at the Market 5 Gallery, both in Washington, D. C.. He co-founded Theater Company. While at the Anacostia Community Museum, he worked on exhibitions such as Blacks in the Westward Movement and Black Women: Achievement Against the Odds, alongside Louise Daniel Hutchinson, he retired in 1994, as director emeritus. His exhibition style was described as "elegant" in The Art Museum as Educator.
James E. Mayo died on July 1995, at George Washington University Hospital of lung cancer. A scholarship named in his honor is awarded by the Erika Thimey Dance and Theater Company
United States
The United States of America known as the United States or America, is a country composed of 50 states, a federal district, five major self-governing territories, various possessions. At 3.8 million square miles, the United States is the world's third or fourth largest country by total area and is smaller than the entire continent of Europe's 3.9 million square miles. With a population of over 327 million people, the U. S. is the third most populous country. The capital is Washington, D. C. and the largest city by population is New York City. Forty-eight states and the capital's federal district are contiguous in North America between Canada and Mexico; the State of Alaska is in the northwest corner of North America, bordered by Canada to the east and across the Bering Strait from Russia to the west. The State of Hawaii is an archipelago in the mid-Pacific Ocean; the U. S. territories are scattered about the Pacific Ocean and the Caribbean Sea, stretching across nine official time zones. The diverse geography and wildlife of the United States make it one of the world's 17 megadiverse countries.
Paleo-Indians migrated from Siberia to the North American mainland at least 12,000 years ago. European colonization began in the 16th century; the United States emerged from the thirteen British colonies established along the East Coast. Numerous disputes between Great Britain and the colonies following the French and Indian War led to the American Revolution, which began in 1775, the subsequent Declaration of Independence in 1776; the war ended in 1783 with the United States becoming the first country to gain independence from a European power. The current constitution was adopted in 1788, with the first ten amendments, collectively named the Bill of Rights, being ratified in 1791 to guarantee many fundamental civil liberties; the United States embarked on a vigorous expansion across North America throughout the 19th century, acquiring new territories, displacing Native American tribes, admitting new states until it spanned the continent by 1848. During the second half of the 19th century, the Civil War led to the abolition of slavery.
By the end of the century, the United States had extended into the Pacific Ocean, its economy, driven in large part by the Industrial Revolution, began to soar. The Spanish–American War and World War I confirmed the country's status as a global military power; the United States emerged from World War II as a global superpower, the first country to develop nuclear weapons, the only country to use them in warfare, a permanent member of the United Nations Security Council. Sweeping civil rights legislation, notably the Civil Rights Act of 1964, the Voting Rights Act of 1965 and the Fair Housing Act of 1968, outlawed discrimination based on race or color. During the Cold War, the United States and the Soviet Union competed in the Space Race, culminating with the 1969 U. S. Moon landing; the end of the Cold War and the collapse of the Soviet Union in 1991 left the United States as the world's sole superpower. The United States is the world's oldest surviving federation, it is a representative democracy.
The United States is a founding member of the United Nations, World Bank, International Monetary Fund, Organization of American States, other international organizations. The United States is a developed country, with the world's largest economy by nominal GDP and second-largest economy by PPP, accounting for a quarter of global GDP; the U. S. economy is post-industrial, characterized by the dominance of services and knowledge-based activities, although the manufacturing sector remains the second-largest in the world. The United States is the world's largest importer and the second largest exporter of goods, by value. Although its population is only 4.3% of the world total, the U. S. holds 31% of the total wealth in the world, the largest share of global wealth concentrated in a single country. Despite wide income and wealth disparities, the United States continues to rank high in measures of socioeconomic performance, including average wage, human development, per capita GDP, worker productivity.
The United States is the foremost military power in the world, making up a third of global military spending, is a leading political and scientific force internationally. In 1507, the German cartographer Martin Waldseemüller produced a world map on which he named the lands of the Western Hemisphere America in honor of the Italian explorer and cartographer Amerigo Vespucci; the first documentary evidence of the phrase "United States of America" is from a letter dated January 2, 1776, written by Stephen Moylan, Esq. to George Washington's aide-de-camp and Muster-Master General of the Continental Army, Lt. Col. Joseph Reed. Moylan expressed his wish to go "with full and ample powers from the United States of America to Spain" to seek assistance in the revolutionary war effort; the first known publication of the phrase "United States of America" was in an anonymous essay in The Virginia Gazette newspaper in Williamsburg, Virginia, on April 6, 1776. The second draft of the Articles of Confederation, prepared by John Dickinson and completed by June 17, 1776, at the latest, declared "The name of this Confederation shall be the'United States of America'".
The final version of the Articles sent to the states for ratification in late 1777 contains the sentence "The Stile of this Confederacy shall be'The United States of America'". In June 1776, Thomas Jefferson wrote the phrase "UNITED STATES OF AMERICA" in all capitalized letters in the headline of his "original Rough draught" of the Declaration of Independence; this draft of the document did not surface unti
Triceratops
Triceratops is a genus of herbivorous ceratopsid dinosaur that first appeared during the late Maastrichtian stage of the late Cretaceous period, about 68 million years ago in what is now North America. It is one of the last known non-avian dinosaur genera, became extinct in the Cretaceous–Paleogene extinction event 66 million years ago; the name Triceratops, which means "three-horned face", is derived from the Ancient Greek words τρί- meaning "three", κέρας meaning "horn", ὤψ meaning "face". It has been documented by numerous remains collected since the genus was first described in 1889, including at least one complete individual skeleton. Paleontologist John Scannella observed: "It is hard to walk out into the Hell Creek Formation and not stumble upon a Triceratops weathering out of a hillside." Forty-seven complete or partial skulls were discovered in just that area from 2000 to 2010. Specimens representing life stages from hatchling to adult have been found; as the archetypal ceratopsid, Triceratops is one of the most popular dinosaurs, has been featured in film, postal stamps, many other types of media.
Bearing a large bony frill and three horns on its large four-legged body, possessing similarities with the modern rhinoceros, Triceratops is one of the most recognizable of all dinosaurs and the best known ceratopsid. It shared the landscape with and was preyed upon by Tyrannosaurus, though it is less certain that the two did battle in the manner depicted in traditional museum displays and popular images; the functions of the frills and three distinctive facial horns on its head have long inspired debate. Traditionally, these have been viewed as defensive weapons against predators. More recent theories, noting the presence of blood vessels in the skull bones of ceratopsids, find it more probable that these features were used in identification and dominance displays, much like the antlers and horns of modern reindeer, mountain goats, or rhinoceros beetles; the theory would find additional support if Torosaurus were found to be the mature form of Triceratops, as this would mean the frill developed holes as individuals reached maturity, rendering the structure more useful for display than defense.
The exact placement of the genus Triceratops within the ceratopsid group has been debated by paleontologists. Two species, T. horridus and T. prorsus, are considered valid, although many other species have been named. Research published in 2010 suggested that the contemporaneous Torosaurus, a ceratopsid long regarded as a separate genus, represents Triceratops in its mature form; the view was disputed and examination of more fossil evidence is expected to settle the debate. Individual Triceratops are estimated to have reached about 7.9 to 9.0 m in length, 2.9 to 3.0 m in height, 6.1–12.0 tonnes in weight. The most distinctive feature is their large skull, among the largest of all land animals; the largest known skull is estimated to have been 2.5 metres in length when complete, could reach a third of the length of the entire animal. A specimen of T. horridus named Kelsey measured 7.3 metres long with a 1.98 metres skull, stood about 2.3 metres tall, was estimated by the Black Hills institute to weight nearly 6 tonnes.
A Triceratops 8 metres long has been estimated by Gregory S. Paul to have massed 9.3 tonnes. It bore a single horn on the snout, above the nostrils, a pair of horns 1 m long, with one above each eye. In 2010, paleontologists revealed a fossil with 115-centimetre-long horn cores and displayed at the Museum of the Rockies in Montana. To the rear of the skull was a short, bony frill, adorned with epoccipitals in some specimens. Most other ceratopsids had large fenestrae in their frills, while those of Triceratops were noticeably solid. T. horridus can be distinguished from T. prorsus by having a shallower snout. Triceratops species possessed a sturdy build, with strong limbs, short hands with three hooves each, short feet with four hooves each. Although quadrupedal, the posture of these dinosaurs has long been the subject of some debate, it was believed that the front legs of the animal had to be sprawling at angles from the thorax in order to better bear the weight of the head. This stance can be seen in paintings by Rudolph Zallinger.
Ichnological evidence in the form of trackways from horned dinosaurs and recent reconstructions of skeletons seem to show that Triceratops and other ceratopsids maintained an upright stance during normal locomotion, with the elbows flexed and bowed out, in an intermediate state between upright and sprawling. The hands and forearms of Triceratops retained a primitive structure compared to other quadrupedal dinosaurs such as thyreophorans and many sauropods. In those two groups, the forelimbs of quadrupedal species were rotated so that the hands faced forward with palms backward as the animals walked. Triceratops, like other ceratopsians and the related quadrupedal ornithopods, walked with most of their fingers pointing out and away from the body, the primitive condition for dinosaurs retained by bipedal forms like the theropods. In Triceratops, the weight of the body was carried by only the first three fingers of the hand, while digits 4 and 5 were vestigial and lacked claws or hooves; the phalangeal formula is 2-3-4-3-1, meaning that the innermost finger of the forelimb has two b
Anacostia
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