A space probe is a robotic spacecraft that does not orbit the Earth, instead, explores further into outer space. A space probe may approach the Moon, travel through space, orbit, or land on other planetary bodies. Approximately fifteen missions are currently operational, once a probe has left the vicinity of Earth, its trajectory will likely take it along an orbit around the Sun similar to the Earths orbit. To reach another planet, the simplest practical method is a Hohmann transfer orbit, more complex techniques, such as gravitational slingshots, can be more fuel-efficient, though they may require the probe to spend more time in transit. Some high Delta-V missions can only be performed, within the limits of modern propulsion, a technique using very little propulsion, but requiring a considerable amount of time, is to follow a trajectory on the Interplanetary Transport Network. First man-made object to land on the Moon, or any other extra terrestrial surface. First mission to photograph the far side of the Moon, launched in 1959, first robotic sample return probe from the Moon.
It was sent to the Moon on November 10,1970, first successful in-place analysis of another planet. It may have been the first space probe to impact the surface of another planet, the Venera 7 probe was the first spacecraft to successfully soft land on another planet and to transmit data from there back to Earth. Upon its arrival at Mars on November 13,1971, Mariner 9 became the first space probe to orbit around another planet. Although, the spacecraft failed shortly after landing, the Mars Exploration Rovers and Opportunity surface and geology, and searched for clues to past water activity on Mars. They were each launched in 2003 and landed in 2004, communication with Spirit stopped on sol 2210. JPL continued to attempt to regain contact until May 24,2011, Opportunity arrived at Endeavour crater on 9 August 2011, at a landmark called Spirit Point named after its rover twin, after traversing 13 miles from Victoria crater, over a three-year period. As of January 26,2016, Opportunity has lasted for more than twelve years on Mars — although the rovers were intended to last only three months.
The first dedicated missions to a comet, in this case and they dropped landers and balloons at Venus before their rendezvous with Halleys Comet. This Japanese probe was the first non-US, non-Soviet interplanetary probe, a second Japanese probe, it made ultraviolet wavelength observations of the comet. The first space probe to penetrate a comets coma and take images of its nucleus. First solar wind sample return probe from sun-earth L1, first sample return probe from a comet tail
It contains the geographic South Pole and is situated in the Antarctic region of the Southern Hemisphere, almost entirely south of the Antarctic Circle, and is surrounded by the Southern Ocean. At 14,000,000 square kilometres, it is the fifth-largest continent, for comparison, Antarctica is nearly twice the size of Australia. About 98% of Antarctica is covered by ice that averages 1.9 km in thickness, Antarctica, on average, is the coldest and windiest continent, and has the highest average elevation of all the continents. Antarctica is a desert, with precipitation of only 200 mm along the coast. The temperature in Antarctica has reached −89.2 °C, though the average for the quarter is −63 °C. Anywhere from 1,000 to 5,000 people reside throughout the year at the research stations scattered across the continent. Organisms native to Antarctica include many types of algae, fungi, protista, where it occurs, is tundra. The continent, remained neglected for the rest of the 19th century because of its hostile environment, lack of easily accessible resources.
In 1895, the first confirmed landing was conducted by a team of Norwegians, Antarctica is a de facto condominium, governed by parties to the Antarctic Treaty System that have consulting status. Twelve countries signed the Antarctic Treaty in 1959, and thirty-eight have signed it since then, the treaty prohibits military activities and mineral mining, prohibits nuclear explosions and nuclear waste disposal, supports scientific research, and protects the continents ecozone. Ongoing experiments are conducted by more than 4,000 scientists from many nations, the name Antarctica is the romanised version of the Greek compound word ἀνταρκτική, feminine of ἀνταρκτικός, meaning opposite to the Arctic, opposite to the north. Aristotle wrote in his book Meteorology about an Antarctic region in c.350 B. C, marinus of Tyre reportedly used the name in his unpreserved world map from the 2nd century A. D. Before acquiring its present geographical connotations, the term was used for locations that could be defined as opposite to the north.
For example, the short-lived French colony established in Brazil in the 16th century was called France Antarctique, the first formal use of the name Antarctica as a continental name in the 1890s is attributed to the Scottish cartographer John George Bartholomew. Antarctica has no population and there is no evidence that it was seen by humans until the 19th century. Explorer Matthew Flinders, in particular, has credited with popularising the transfer of the name Terra Australis to Australia. Cook came within about 120 km of the Antarctic coast before retreating in the face of ice in January 1773. The first confirmed sighting of Antarctica can be narrowed down to the crews of ships captained by three individuals, according to various organisations, ships captained by three men sighted Antarctica or its ice shelf in 1820, von Bellingshausen, Edward Bransfield, and Nathaniel Palmer
Walter Elias Walt Disney was an American entrepreneur, voice actor and film producer. A pioneer of the American animation industry, he introduced several developments in the production of cartoons, as a film producer, Disney holds the record for most Academy Awards earned by an individual, having won 22 Oscars from 59 nominations. He was presented with two Golden Globe Special Achievement Awards and an Emmy Award, among other honors, several of his films are included in the National Film Registry by the Library of Congress. Born in Chicago in 1901, Disney developed an early interest in drawing and he took art classes as a boy and got a job as a commercial illustrator at the age of 18. He moved to California in the early 1920s and set up the Disney Brothers Studio with his brother Roy, with Ub Iwerks, Walt developed the character Mickey Mouse in 1928, his first highly popular success, he provided the voice for his creation in the early years. As the studio grew, Disney became more adventurous, introducing synchronized sound, full-color three-strip Technicolor, feature-length cartoons, the results, seen in features such as Snow White and the Seven Dwarfs, Pinocchio and Bambi, furthered the development of animated film.
New animated and live-action films followed after World War II, including the critically successful Cinderella and Mary Poppins, in the 1950s, Disney expanded into the amusement park industry, and in 1955 he opened Disneyland. In 1965, he began development of theme park, Disney World, the heart of which was to be a new type of city. Disney was a smoker throughout his life, and died of lung cancer in December 1966 before either the park or the EPCOT project were completed. Disney was a shy, self-deprecating and insecure man in private and he had high standards and high expectations of those with whom he worked. Although there have been accusations that he was racist or anti-semitic and his reputation changed in the years after his death, from a purveyor of homely patriotic values to a representative of American imperialism. Nevertheless, Disney is considered an icon, particularly in the United States. Walt Disney was born on December 5,1901, at 1249 Tripp Avenue and he was the fourth son of Elias Disney—born in the Province of Canada, to Irish parents—and Flora, an American of German and English descent.
Aside from Disney and Calls sons were Herbert and Roy, in 1906, when Disney was four, the family moved to a farm in Marceline, where his uncle Robert had just purchased land. In Marceline, Disney developed his interest in drawing when he was paid to draw the horse of a neighborhood doctor. Elias was a subscriber to the Appeal to Reason newspaper, Disney began to develop an ability to work with watercolors and crayons. He lived near the Atchison and Santa Fe Railway line and he and his younger sister Ruth started school at the same time at the Park School in Marceline in late 1909. In 1911, the Disneys moved to Kansas City, before long, he was spending more time at the Pfeiffers house than at home
World War II
World War II, known as the Second World War, was a global war that lasted from 1939 to 1945, although related conflicts began earlier. It involved the vast majority of the worlds countries—including all of the great powers—eventually forming two opposing alliances, the Allies and the Axis. It was the most widespread war in history, and directly involved more than 100 million people from over 30 countries. Marked by mass deaths of civilians, including the Holocaust and the bombing of industrial and population centres. These made World War II the deadliest conflict in human history, from late 1939 to early 1941, in a series of campaigns and treaties, Germany conquered or controlled much of continental Europe, and formed the Axis alliance with Italy and Japan. Under the Molotov–Ribbentrop Pact of August 1939, Germany and the Soviet Union partitioned and annexed territories of their European neighbours, Finland and the Baltic states. In December 1941, Japan attacked the United States and European colonies in the Pacific Ocean, and quickly conquered much of the Western Pacific.
The Axis advance halted in 1942 when Japan lost the critical Battle of Midway, near Hawaii, in 1944, the Western Allies invaded German-occupied France, while the Soviet Union regained all of its territorial losses and invaded Germany and its allies. During 1944 and 1945 the Japanese suffered major reverses in mainland Asia in South Central China and Burma, while the Allies crippled the Japanese Navy, thus ended the war in Asia, cementing the total victory of the Allies. World War II altered the political alignment and social structure of the world, the United Nations was established to foster international co-operation and prevent future conflicts. The victorious great powers—the United States, the Soviet Union, the United Kingdom, the Soviet Union and the United States emerged as rival superpowers, setting the stage for the Cold War, which lasted for the next 46 years. Meanwhile, the influence of European great powers waned, while the decolonisation of Asia, most countries whose industries had been damaged moved towards economic recovery.
Political integration, especially in Europe, emerged as an effort to end pre-war enmities, the start of the war in Europe is generally held to be 1 September 1939, beginning with the German invasion of Poland and France declared war on Germany two days later. The dates for the beginning of war in the Pacific include the start of the Second Sino-Japanese War on 7 July 1937, or even the Japanese invasion of Manchuria on 19 September 1931. Others follow the British historian A. J. P. Taylor, who held that the Sino-Japanese War and war in Europe and its colonies occurred simultaneously and this article uses the conventional dating. Other starting dates sometimes used for World War II include the Italian invasion of Abyssinia on 3 October 1935. The British historian Antony Beevor views the beginning of World War II as the Battles of Khalkhin Gol fought between Japan and the forces of Mongolia and the Soviet Union from May to September 1939, the exact date of the wars end is not universally agreed upon.
It was generally accepted at the time that the war ended with the armistice of 14 August 1945, rather than the formal surrender of Japan
The crater Ley on the far side of the Moon is named in his honor. Willy Otto Oskar Ley was the son of Julius Otto Ley, a merchant, and Frida May. Ley grew up in his native Berlin during the First World War under the supervision of two aunts, when war erupted, his father was in Great Britain. Consequently, he spent the remainder of the war at a camp on the Isle of Man. Meanwhile, his mother worked as milliner in a distant city in Germany, as Ley recalled, he grew up, so to speak, in the shadow of the Museum of Natural History in Berlin, where he spent Sundays exploring the exhibits and asking questions. When his school teacher asked him to compose an essay on the subject What Do I Want to Be When I Am Grown, Ley responded, I want to be an explorer. To his dismay, the teacher thought this silly, especially for someone of his family background, what was left to explore in the twentieth century. Ley remained unconvinced by this skeptical attitude, when he was old enough, he studied astronomy, physics and paleontology at the University of Berlin.
He became interested in spaceflight after reading Hermann Oberths book Die Rakete zu den Planetenräumen, although it was a technical book that was difficult to understand, Ley worked through the calculations and concluded that outer space would soon become the next great frontier of human exploration. Ley was so convinced by Oberths book that he sat down to write a popularization of its contents and he began corresponding with every known rocket enthusiast in Europe, including Oberth himself. Ley would eventually become the groups Vice-President, during a time when it had no active President, meanwhile, he was writing hundreds of short articles about rockets for German and foreign newspapers. Due to the influence of Ley and other popular writers, such as Max Valier. The rocketry fad culminated with Fritz Langs 1929 film Die Frau im Mond, although Oberth is often credited as the main technical consultant to the film, Leys role was of central importance. Oberth was tasked with building a rocket, to be launched at the films premiere.
However, Leys work on the movie did, as director Fritz Lang recalled, The work he had done as consultant and advisor. was amazing. The models of the spaceship, really a highly advanced model of a rocket, the trajectories and the orbits of the capsule from the earth, around the earth. Were so accurate that in 1937 the Gestapo confiscated not only all models of the spaceship, despite the many successes, the rocketry fad could not be sustained during the early years of the Great Depression. The German public lost interest amidst economic turmoil, rocket researchers, such as Rudolf Nebel, formed closer ties with the military, which greatly expanded under the leadership of Wernher von Braun
A foreword is a piece of writing sometimes placed at the beginning of a book or other piece of literature. Typically written by other than the primary author of the work. Later editions of a book sometimes have a new foreword prepended, unlike a preface, a foreword is always signed. Information essential to the text is generally placed in a set of explanatory notes, or perhaps in an introduction. The pages containing the foreword and preface are typically not numbered as part of the main work, if the front matter is paginated, it uses lowercase Roman numerals. If there is both a foreword and a preface, the foreword appears first, both appear before the introduction, which may be paginated either with the front matter or the main text, the word foreword was first used around the mid-17th century. It was possibly a translation of Dutch voorwoord or German Vorwort. Afterword Epigraph Introduction Preface Prologue The difference between a preface and introduction – PatMcNees. com
Urbana /ɜːrˈbænə/ is a city in and the county seat of Champaign County, United States. The population was 41,250 at the 2010 census, Urbana is the tenth-most populous city in Illinois outside of the Chicago metropolitan area. Most of the campus of the University of Illinois at Urbana-Champaign is located in Urbana, the Urbana area was first settled in 1822, when it was called Big Grove. The creation of the new town was celebrated for the first time in July 4,1833, the first mills were founded c. 1838-50, and stores began opening beginning in 1834. The towns first church was built c.1840, with the Baptist Church following in 1855, the Presbyterian Church was founded in 1856. The citys first school was built in 1854, Urbana suffered a setback when the Chicago branch of the Illinois Central Railroad, which had been expected to pass through town, was instead laid down two miles west, where the land was flatter. The town of West Urbana grew up around the depot built there in 1854. Champaign-Urbana was selected as the site for a new agricultural school.
Illinois Industrial University, which would evolve into the University of Illinois at Urbana-Champaign, a number of efforts to merge Urbana and Champaign have failed at the polls. On October 9,1871 a fire burned much of downtown Urbana, children playing with matches started the fire. Downtown Urbana is located southwest of the intersection of its two busiest streets, U. S.150 and U. S.45, most of Urbana lies south of I-74. There are three exits, Lincoln and University, the Lincoln exit is closest to the University of Illinois, while the Cunningham exit goes to downtown Urbana. The University exit goes to downtown Urbana as well as Illinois Route 130 to Philo, the Norfolk Southern operates an east to west line through Urbana. The NS line connects industries in eastern Urbana to the Norfolk Southern main line at Mansfield, construction of the line was begun by the Danville, Urbana and Pekin Railroad. This short-lived entity became part of the Indianapolis and Western Railway before the railroad was completed, as of the census of 2000, there were 36,395 people,14,327 households, and 6,217 families residing in the city.
The population density was 3,468.3 people per square mile, there were 15,311 housing units at an average density of 1,459. 1/sq mi. The racial makeup of the city was 67. 01% White,14. 34% African American,0. 18% Native American,14. 24% Asian,0. 04% Pacific Islander,1. 76% from other races, and 2. 45% from two or more races. Hispanic or Latino of any race were 3. 54% of the population,36. 6% of all households were made up of individuals and 8. 1% had someone living alone who was 65 years of age or older
Health threat from cosmic rays
Galactic cosmic rays consist of high energy protons and other high energy nuclei. Solar energetic particles consist primarily of protons accelerated by the Sun to high energies via proximity to solar flares and they are one of the most important barriers standing in the way of plans for interplanetary travel by crewed spacecraft. Heavy ions and low energy protons and helium particles are highly ionizing forms of radiation, in October 2015, the NASA Office of Inspector General issued a health hazards report related to space exploration, including a human mission to Mars. But of course the radiation belts are in low Earth orbit and do not occur in deep space, the solar cycle is an approximately 11-year period of varying solar activity including solar maximum where the solar wind is strongest and solar minimum where the solar wind is weakest. Galactic cosmic rays create a continuous radiation dose throughout the Solar System that increases during solar minimum, the inner and outer radiation belts are two regions of trapped particles from the solar wind that are accelerated by dynamic interaction with the Earths magnetic field.
While always high, the dose in these belts can increase dramatically during geomagnetic storms and substorms. Solar proton events are bursts of energetic protons accelerated by the Sun and they occur relatively rarely and can produce extremely high radiation levels. Without thick shielding, SPEs are sufficiently strong to cause radiation poisoning. The secondary radiation is attenuated by absorption in the atmosphere, as well as by radioactive decay in flight of some particles. Particles entering from a close to the horizon are especially attenuated. The worlds population receives an average of 0.4 millisieverts of cosmic radiation annually due to atmospheric shielding, except for the very highest energy galactic cosmic rays, the radius of gyration in the Earths magnetic field is small enough to ensure that they are deflected away from Earth. Missions beyond low Earth orbit leave the protection of the geomagnetic field, thus they may need to be shielded against exposure to cosmic rays, Van Allen radiation, or solar flares.
The region between two and four Earth radii lies between the two belts and is sometimes referred to as the safe zone. See the implications of the Van Allen belts for space travel for more information, the interplanetary magnetic field, embedded in the solar wind, deflects cosmic rays. As a result, cosmic ray fluxes within the heliopause are inversely correlated with the solar cycle, as a result, the energy input of GCRs to the atmosphere is negligible – about 10−9 of solar radiation – roughly the same as starlight. Of the above factors, all but the first one apply to low Earth orbit craft, such as the Space Shuttle, exposures on the ISS average 150 mSv per year, although frequent crew rotations minimize individual risk. Astronauts on Apollo and Skylab missions received on average 1.2 mSv/day and 1.4 mSv/day respectively, acute effects result from high radiation doses, and these are most likely to occur after solar particle events. Likely chronic effects of radiation exposure include both stochastic events such as radiation carcinogenesis and deterministic degenerative tissue effects
Exploration of Mars
The exploration of Mars is the study of Mars by spacecraft. Engineering interplanetary journeys is complicated and the exploration of Mars has experienced a failure rate. Roughly two-thirds of all spacecraft destined for Mars failed before completing their missions, some missions have met with unexpected success, such as the twin Mars Exploration Rovers, which operated for years beyond their specification. No sample return missions have attempted for Mars and an attempted return mission for Mars moon Phobos failed. The search for evidence of habitability and organic carbon on the planet Mars is now a primary NASA objective, Mars has long been the subject of human interest. Early telescopic observations revealed color changes on the surface that were attributed to seasonal vegetation, further telescopic observations found two moons and Deimos, polar ice caps and the feature now known as Olympus Mons, the solar systems tallest mountain. The discoveries piqued further interest in the study and exploration of the red planet.
Mars is a planet, like Earth, that formed around the same time, yet with only half the diameter of Earth. The minimum-energy launch windows for a Martian expedition occur at intervals of two years and two months. In addition, the lowest available transfer energy varies on a roughly 16-year cycle, for example, a minimum occurred in the 1969 and 1971 launch windows, rising to a peak in the late 1970s, and hitting another low in 1986 and 1988. Starting in 1960, the Soviets launched a series of probes to Mars including the first intended flybys, the first successful fly-by of Mars was on 14–15 July 1965, by NASAs Mariner 4. On November 14,1971 Mariner 9 became the first space probe to orbit another planet when it entered orbit around Mars. The amount of data returned by probes increased dramatically as technology improved, Mars 6 failed during descent but did return some corrupted atmospheric data in 1974. The 1975 NASA launches of the Viking program consisted of two orbiters, each with a lander that successfully landed in 1976.
Viking 1 remained operational for six years, Viking 2 for three, the Viking landers relayed the first color panoramas of Mars. The Soviet probes Phobos 1 and 2 were sent to Mars in 1988 to study Mars, Phobos 1 lost contact on the way to Mars. Phobos 2, while successfully photographing Mars and Phobos, failed before it was set to release two landers to the surface of Phobos, roughly two-thirds of all spacecraft destined for Mars have failed without completing their missions, and it has a reputation as a difficult space exploration target. This mission was a success, having finished its primary mapping mission in early 2001
Atmosphere of Mars
The atmosphere of Mars is the layer of gases surrounding Mars. It is composed mostly of carbon dioxide, the atmospheric pressure on the Martian surface averages 600 pascals, about 0. 6% of Earths mean sea level pressure of 101.3 kilopascals. It ranges from a low of 30 pascals on Olympus Monss peak to over 1,155 pascals in the depths of Hellas Planitia and this pressure is well below the Armstrong limit for the unprotected human body. Marss atmospheric mass of 25 teratonnes compares to Earths 5148 teratonnes with a height of about 11 kilometres versus Earths 7 kilometres. On 16 December 2014, NASA reported detecting an increase, decrease. Organic chemicals have been detected in powder drilled from a rock by the Curiosity rover, on 18 March 2015, NASA reported the detection of an aurora that is not fully understood and an unexplained dust cloud in the atmosphere of Mars. On 4 April 2015, NASA reported studies, based on measurements by the Sample Analysis at Mars instrument on the Curiosity rover, of the Martian atmosphere using xenon and argon isotopes.
This was further supported by results from the MAVEN orbiter circling Mars, Marss atmosphere is composed of the following layers, Typically stated to start at 200 km and higher, this region is where the last wisps of atmosphere merge into the vacuum of space. There is no boundary where the atmosphere ends, it just tapers away. Upper atmosphere, or thermosphere, A region with high temperatures. Atmospheric gases start to separate from each other at these altitudes, middle atmosphere, The region in which Marss jetstream flows. Lower atmosphere, A relatively warm region affected by heat from airborne dust, there is a complicated ionosphere, and a seasonal ozone layer over the south pole. The MAVEN spacecraft determined in 2015 that there is a layered structure present in both neutral gases and ion densities. Spectroscopic observations in the 1860s and 1870s led many to think the atmosphere of Mars is similar to Earths, in 1894, spectral analysis and other qualitative observations by William Wallace Campbell suggested Mars resembles the Moon, which has no appreciable atmosphere, in many respects.
In 1926, photographic observations by William Hammond Wright at the Lick Observatory allowed Donald Howard Menzel to discover evidence of Marss atmosphere. The main component of the atmosphere of Mars is carbon dioxide at 95. 9%, each pole is in continual darkness during its hemispheres winter, and the surface gets so cold that as much as 25% of the atmospheric CO2 condenses at the polar caps into solid CO2 ice. When the pole is exposed to sunlight during summer, the CO2 ice sublimes back into the atmosphere. This process leads to a significant annual variation in the atmospheric pressure and it has been suggested that Mars had a much thicker and wetter atmosphere early in its history
Rose Center for Earth and Space
The Rose Center for Earth and Space is a part of the American Museum of Natural History in New York City. The Centers complete name is The Frederick Phineas and Sandra Priest Rose Center for Earth, the main entrance is located on the northern side of the museum on 81st Street near Central Park West in Manhattans Upper West Side. Completed in 2000, it includes the new Hayden Planetarium, the original of which was opened in 1935, Neil deGrasse Tyson is its first and, to date, only director. The center is a reworking of the former Hayden Planetarium, whose first projector. The original Hayden Planetarium was founded in 1933 with a donation by philanthropist Charles Hayden and its mission was to give the public a more lively and sincere appreciation of the magnitude of the universe. And for the things which are daily occurring in the universe. Joseph M. Chamberlain, hired as an assistant curator in 1952, in 1960, a Zeiss Mark IV projector was installed, followed by a Zeiss Mark VI projector and new seats in 1993.
In January 1997, the original Hayden Planetarium was closed and demolished, on February 19,2000, the $210 million Frederick Phineas and Sandra Priest Rose Center for Earth and Space, containing the new Hayden Planetarium, opened to the public. Tom Hanks provided the voice-over for the first planetarium show during the opening of the new Rose Center for Earth & Space in the Hayden Planetarium in 2000, since such celebrities as Whoopi Goldberg, Robert Redford, Harrison Ford, Liam Neeson and Maya Angelou have been featured. Polshek has referred to work as a cosmic cathedral. Also located in the facility is the Department of Astrophysics, the newest academic research department in the Museum, Polshek designed the 1, 800-square-foot Weston Pavilion, a 43-foot high transparent structure of water white glass along the Museums west facade. This structure, a companion piece to the Rose Center, offers a new entry way to the Museum. The planetariums original magazine, The Sky, merged with another journal, The Telescope, the exhibits highlight human connection to the cosmos along with the scale and properties of the observable universe itself.
When the new Rose Center opened with a model of only eight planets, excluding Pluto, the Hayden Planetarium has, since 2000, been one of the two main attractions within the Rose Center. It was established by the State of New York in 1933, the Big Bang Theater, which occupies the bottom half of the Hayden Sphere, depicts the birth of the universe in a four-minute program. Utilizing a screen that measures 36 feet in diameter over an 8-foot-deep bowl, the Big Bang Theater serves as an introduction to the Heilbrun Cosmic Pathway, a spiral which wraps around the sphere, connecting the second and first floors of the Rose Center. The cosmic pathway provides a timeline of the history from the Big Bang to the present day. The Heilbrun Cosmic Pathway is one of the most popular exhibits in the Rose Center, the Hayden Planetarium offers a number of courses and public presentations including the Frontiers of Astrophysics and Distinguished Authors lecture series
A hardcover or hardback book is one bound with rigid protective covers. It has a flexible, sewn spine which allows the book to lie flat on a surface when opened, following the ISBN sequence numbers, books of this type may be identified by the abbreviation Hbk. Hardcover books are printed on acid-free paper, and are much more durable than paperbacks. Hardcover books are more costly to manufacture. If brisk sales are anticipated, an edition of a book is typically released first. Some publishers publish paperback originals if slow hardback sales are anticipated, for very popular books these sales cycles may be extended, and followed by a mass market paperback edition typeset in a more compact size and printed on shallower, less hardy paper. In the past the release of an edition was one year after the hardback. It is very unusual for a book that was first published in paperback to be followed by a hardback, an example is the novel The Judgment of Paris by Gore Vidal, which had its revised edition of 1961 first published in paperback, and in hardcover.
Hardcover books are sold at higher prices than comparable paperbacks. Hardcovers typically consist of a block, two boards, and a cloth or heavy paper covering. The pages are sewn together and glued onto a flexible spine between the boards, and it too is covered by the cloth, a paper wrapper, or dust jacket, is usually put over the binding, folding over each horizontal end of the boards. On the folded part, or flap, over the front cover is generally a blurb, the back flap is where the biography of the author can be found. Reviews are often placed on the back of the jacket, bookbinding Paperback How to make a simple Hardcover book