1.
Outer planets
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It has four very large satellites. Saturn is the second-largest planet, with a large and bright ring system, Uranus is the third-largest planet and the least massive of the four outer planets. It is tilted almost onto the plane of its orbit, neptune is the fourth-largest planet, as smallest of the four outer planets, but third-most massive. It has one big retrograde moon and many small ones, the outer planets all have ring systems, although all but Saturns are faint when viewed from Earth. Another aspect common to the gas giants is their natural satellites. That pair and Io, Callisto, Europa, and Triton, are larger than Pluto and this region of space is also occupied by centaurs, various fields of trojans, and many comets. Pluto was considered to be a planet from its discovery in 1930 until its reclassification as a dwarf planet in 2006. In situ exploration by spacecraft includes Pioneer 10, Pioneer 11, Voyager 1, Voyager 2, Ulysses, Galileo, Cassini–Huygens, planned missions include Juno Jupiter Orbiter and possibly the Outer Planet Flagship Missions, there are various proposals too, such as Uranus orbiter and probe. Ongoing missions for the planets as of 2011 include Cassini probe, orbiting Saturn, New Horizons, headed for Pluto. Cassini and New Horizons also visited Jupiter with a flyby, one of the breakthroughs that made exploration of the outer planets much easier, was the concept of the planetary gravity assist. Discovered in the 1960s, a spacecraft approaches a planet like Jupiter in such a way as to be accelerated to a higher speed and this allows a much smaller rocket to be used for a given launch. Another promising technology, tested on Deep Space 1, is the ion engine, ion engines can make much more efficient use of propellant than existing chemical rockets. S. Centennial of Flight Commission - Exploration of the Outer Planets Space Probes to the Outer Planets
2.
William Blake
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William Blake was an English poet, painter, and printmaker. Largely unrecognised during his lifetime, Blake is now considered a figure in the history of the poetry. His so-called prophetic works were said by 20th century critic Northrop Frye to form what is in proportion to its merits the least read body of poetry in the English language. His visual artistry led 21st-century critic Jonathan Jones to proclaim him far, in 2002, Blake was placed at number 38 in the BBCs poll of the 100 Greatest Britons. Although he lived in London his entire life, he produced a diverse and symbolically rich œuvre and his paintings and poetry have been characterised as part of the Romantic movement and as Pre-Romantic. Reverent of the Bible but hostile to the Church of England, Blake was influenced by the ideals and ambitions of the French, despite these known influences, the singularity of Blakes work makes him difficult to classify. William Blake was born on 28 November 1757 at 28 Broad Street in Soho and he was the third of seven children, two of whom died in infancy. Blakes father, James, was a hosier and he attended school only long enough to learn reading and writing, leaving at the age of ten, and was otherwise educated at home by his mother Catherine Blake. Even though the Blakes were English Dissenters, William was baptised on 11 December at St Jamess Church, Piccadilly, the Bible was an early and profound influence on Blake, and remained a source of inspiration throughout his life. Blake started engraving copies of drawings of Greek antiquities purchased for him by his father, within these drawings Blake found his first exposure to classical forms through the work of Raphael, Michelangelo, Maarten van Heemskerck and Albrecht Dürer. The number of prints and bound books that James and Catherine were able to purchase for young William suggests that the Blakes enjoyed, at least for a time, a comfortable wealth. When William was ten years old, his parents knew enough of his headstrong temperament that he was not sent to school and he read avidly on subjects of his own choosing. During this period, Blake made explorations into poetry, his work displays knowledge of Ben Jonson, Edmund Spenser. On 4 August 1772, Blake was apprenticed to engraver James Basire of Great Queen Street, at the sum of £52.10, at the end of the term, aged 21, he became a professional engraver. This aside, Basires style of line-engraving was of a kind held at the time to be old-fashioned compared to the flashier stipple or mezzotint styles. It has been speculated that Blakes instruction in this form may have been detrimental to his acquiring of work or recognition in later life. After two years, Basire sent his apprentice to copy images from the Gothic churches in London and his experiences in Westminster Abbey helped form his artistic style and ideas. The Abbey of his day was decorated with suits of armour, painted funeral effigies, ackroyd notes that. the most immediate would have been of faded brightness and colour
3.
Pluto
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Pluto is a dwarf planet in the Kuiper belt, a ring of bodies beyond Neptune. It was the first Kuiper belt object to be discovered, Pluto was discovered by Clyde Tombaugh in 1930 and was originally considered to be the ninth planet from the Sun. After 1992, its planethood was questioned following the discovery of objects of similar size in the Kuiper belt. In 2005, Eris, which is 27% more massive than Pluto, was discovered and this led the International Astronomical Union to define the term planet formally in 2006, during their 26th General Assembly. That definition excluded Pluto and reclassified it as a dwarf planet, Pluto is the largest and second-most-massive known dwarf planet in the Solar System and the ninth-largest and tenth-most-massive known object directly orbiting the Sun. It is the largest known trans-Neptunian object by volume but is less massive than Eris, like other Kuiper belt objects, Pluto is primarily made of ice and rock and is relatively small—about one-sixth the mass of the Moon and one-third its volume. It has an eccentric and inclined orbit during which it ranges from 30 to 49 astronomical units or AU from the Sun. This means that Pluto periodically comes closer to the Sun than Neptune, light from the Sun takes about 5.5 hours to reach Pluto at its average distance. Pluto has five moons, Charon, Styx, Nix, Kerberos. Pluto and Charon are sometimes considered a system because the barycenter of their orbits does not lie within either body. The IAU has not formalized a definition for binary dwarf planets, on July 14,2015, the New Horizons spacecraft became the first spacecraft to fly by Pluto. During its brief flyby, New Horizons made detailed measurements and observations of Pluto, on October 25,2016, at 05,48 pm ET, the last bit of data was received from New Horizons from its close encounter with Pluto on July 14,2015. In the 1840s, Urbain Le Verrier used Newtonian mechanics to predict the position of the then-undiscovered planet Neptune after analysing perturbations in the orbit of Uranus. Subsequent observations of Neptune in the late 19th century led astronomers to speculate that Uranuss orbit was being disturbed by another planet besides Neptune, by 1909, Lowell and William H. Pickering had suggested several possible celestial coordinates for such a planet. Lowell and his observatory conducted his search until his death in 1916, unknown to Lowell, his surveys had captured two faint images of Pluto on March 19 and April 7,1915, but they were not recognized for what they were. There are fourteen other known prediscovery observations, with the oldest made by the Yerkes Observatory on August 20,1909. Percivals widow, Constance Lowell, entered into a legal battle with the Lowell Observatory over her late husbands legacy. Tombaughs task was to image the night sky in pairs of photographs, then examine each pair
4.
Charon (moon)
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Charon, also known as Pluto I, is the largest of the five known natural satellites of the dwarf planet Pluto. It was discovered in 1978 at the United States Naval Observatory in Washington, with half the diameter and one eighth the mass of Pluto, it is a very large moon in comparison to its parent body. Its gravitational influence is such that the barycenter of the Pluto–Charon system lies outside Pluto, the New Horizons spacecraft is the only probe that has visited the Pluto system. It approached Charon to within 27,000 km, Charon was discovered by United States Naval Observatory astronomer James Christy, using the 1. 55-meter Flagstaff telescope two months prior. Christy noticed that a slight elongation appeared periodically, later, the bulge was confirmed on plates dating back to April 29,1965. Subsequent observations of Pluto determined that the bulge was due to an accompanying body. The periodicity of the bulge corresponded to Plutos rotation period, which was known from Plutos light curve. This indicated a synchronous orbit, which suggested that the bulge effect was real. Doubts about Charons existence were erased when it and Pluto entered a period of mutual eclipses. This occurs when the Pluto–Charon orbital plane is edge-on as seen from Earth and it was fortuitous that one of these intervals happened to occur soon after Charons discovery. Charon was originally known by the temporary designation S/1978 P1, on June 24,1978, Christy first suggested the name Charon as a scientific-sounding version of his wife Charlenes nickname, Char. The IAU officially adopted the name in late 1985 and it was announced on January 3,1986, there is minor debate over the preferred pronunciation of the name. These indicate only one pronunciation of Charon when referring specifically to Plutos moon, speakers of many languages other than English, and many English-speaking astronomers as well, follow this pronunciation. However, Christy himself pronounced the ch as sh, after his wife Charlene, simulation work published in 2005 by Robin Canup suggested that Charon could have been formed by a collision around 4.5 billion years ago, much like Earth and the Moon. In this model, a large Kuiper belt object struck Pluto at high velocity, destroying itself and blasting off much of Plutos outer mantle, however, such an impact should result in an icier Charon and rockier Pluto than scientists have found. It is now thought that Pluto and Charon might have been two bodies that collided before going into orbit about each other, the collision would have been violent enough to boil off volatile ices like methane but not violent enough to have destroyed either body. The very similar density of Pluto and Charon implies that the parent bodies were not fully differentiated when the impact occurred, Charon and Pluto orbit each other every 6.387 days. The two objects are locked to one another, so each keeps the same face towards the other
5.
Hawaii
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Hawaii is the 50th and most recent state to have joined the United States of America, having received statehood on August 21,1959. Hawaii is the only U. S. state located in Oceania and it is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean. Hawaii is the only U. S. state not located in the Americas, the state encompasses nearly the entire volcanic Hawaiian archipelago, which comprises hundreds of islands spread over 1,500 miles. At the southeastern end of the archipelago, the eight main islands are—in order from northwest to southeast, Niʻihau, Kauaʻi, Oʻahu, Molokaʻi, Lānaʻi, Kahoʻolawe, Maui, and the Island of Hawaiʻi. The last is the largest island in the group, it is called the Big Island or Hawaiʻi Island to avoid confusion with the state or archipelago. The archipelago is physiographically and ethnologically part of the Polynesian subregion of Oceania, Hawaii has over a million permanent residents, along with many visitors and U. S. military personnel. Its capital is Honolulu on the island of Oʻahu, Hawaii is the 8th-smallest and the 11th-least populous, but the 13th-most densely populated of the fifty U. S. states. It is the state with an Asian plurality. The states coastline is about 750 miles long, the fourth longest in the U. S. after the coastlines of Alaska, Florida, the state of Hawaii derives its name from the name of its largest island, Hawaiʻi. A common Hawaiian explanation of the name of Hawaiʻi is that was named for Hawaiʻiloa and he is said to have discovered the islands when they were first settled. The Hawaiian language word Hawaiʻi is very similar to Proto-Polynesian *Sawaiki, cognates of Hawaiʻi are found in other Polynesian languages, including Māori, Rarotongan and Samoan. According to linguists Pukui and Elbert, lsewhere in Polynesia, Hawaiʻi or a cognate is the name of the underworld or of the home, but in Hawaii. A somewhat divisive political issue arose in 1978 when the Constitution of the State of Hawaii added Hawaiian as an official state language. The title of the constitution is The Constitution of the State of Hawaii. Article XV, Section 1 of the Constitution uses The State of Hawaii, diacritics were not used because the document, drafted in 1949, predates the use of the okina and the kahakō in modern Hawaiian orthography. The exact spelling of the name in the Hawaiian language is Hawaiʻi. In the Hawaii Admission Act that granted Hawaiian statehood, the government recognized Hawaii as the official state name. Official government publications, department and office titles, and the Seal of Hawaii use the spelling with no symbols for glottal stops or vowel length
6.
Mauna Kea Observatories
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The facilities are located in a 525-acre special land use zone known as the Astronomy Precinct, which is located within the 11, 228-acre Mauna Kea Science Reserve. The Astronomy Precinct was established in 1967 and is located on land protected by the Historical Preservation Act for its significance to Hawaiian culture. After studying photos for NASAs Apollo program that contained greater detail than any ground based telescope, while he first began looking in Chile, he also made the decision to perform tests in the Hawaiian Islands. Tests on Mauis Haleakalā were promising, but the mountain was too low in the inversion layer, on the Big Island of Hawaiʻi, Mauna Kea is considered the highest island mountain in the world. While the summit is covered with snow, the air is extremely dry. Kuiper began looking into the possibility of an observatory on Mauna Kea, after testing, he discovered the low humidity was perfect for infrared signals. He persuaded Hawaiʻi Governor John A. Burns to bulldoze a road to the summit where he built a small telescope on Puʻu Poliʻahu. The peak was the second highest on the mountain with the highest peak being holy ground, next, Kuiper tried enlisting NASA to fund a larger facility with a large telescope, housing and other needed structures. NASA, in turn decided to make the open to competition. Professor of physics, John Jefferies of the University of Hawaii placed a bid on behalf of the university, Jefferies had gained his reputation through observations at Sacramento Peak Observatory. The proposal was for a telescope to serve both the needs of NASA and the university. Kuiper would abandon his site over the competition and begin work in Arizona on a different NASA project, after considerable testing by Jefferies team, the best locations were determined to be near the summit at the top of the cinder cones. Testing also determined Mauna Kea to be superb for nighttime viewing due to many factors, including the air, constant trade winds. Jefferies would build a 2.24 meter telescope with the State of Hawaiʻi agreeing to build a reliable, building began in 1967 and first light was seen in 1970. Other groups began requesting subleases on the newly accessible mountaintop, by 1970, two 24 in telescopes had been constructed by the United States Air Force and Lowell Observatory. In 1973, Canada and France agreed to build the 3.6 m CFHT on Mauna Kea, however, local organizations started to raise concerns about the environmental impact of the observatory. This led the Department of Land and Natural Resources to prepare a management plan, drafted in 1977. In January 1982, the University of Hawaiʻi Board of Regents approved a plan to support the development of scientific facilities at the site
7.
Apparent magnitude
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The apparent magnitude of a celestial object is a number that is a measure of its brightness as seen by an observer on Earth. The brighter an object appears, the lower its magnitude value, the Sun, at apparent magnitude of −27, is the brightest object in the sky. It is adjusted to the value it would have in the absence of the atmosphere, furthermore, the magnitude scale is logarithmic, a difference of one in magnitude corresponds to a change in brightness by a factor of 5√100, or about 2.512. The measurement of apparent magnitudes or brightnesses of celestial objects is known as photometry, apparent magnitudes are used to quantify the brightness of sources at ultraviolet, visible, and infrared wavelengths. An apparent magnitude is measured in a specific passband corresponding to some photometric system such as the UBV system. In standard astronomical notation, an apparent magnitude in the V filter band would be denoted either as mV or often simply as V, the scale used to indicate magnitude originates in the Hellenistic practice of dividing stars visible to the naked eye into six magnitudes. The brightest stars in the sky were said to be of first magnitude, whereas the faintest were of sixth magnitude. Each grade of magnitude was considered twice the brightness of the following grade and this rather crude scale for the brightness of stars was popularized by Ptolemy in his Almagest, and is generally believed to have originated with Hipparchus. This implies that a star of magnitude m is 2.512 times as bright as a star of magnitude m +1 and this figure, the fifth root of 100, became known as Pogsons Ratio. The zero point of Pogsons scale was defined by assigning Polaris a magnitude of exactly 2. However, with the advent of infrared astronomy it was revealed that Vegas radiation includes an Infrared excess presumably due to a disk consisting of dust at warm temperatures. At shorter wavelengths, there is negligible emission from dust at these temperatures, however, in order to properly extend the magnitude scale further into the infrared, this peculiarity of Vega should not affect the definition of the magnitude scale. Therefore, the scale was extrapolated to all wavelengths on the basis of the black body radiation curve for an ideal stellar surface at 11000 K uncontaminated by circumstellar radiation. On this basis the spectral irradiance for the zero magnitude point, with the modern magnitude systems, brightness over a very wide range is specified according to the logarithmic definition detailed below, using this zero reference. In practice such apparent magnitudes do not exceed 30, astronomers have developed other photometric zeropoint systems as alternatives to the Vega system. The AB magnitude zeropoint is defined such that an objects AB, the dimmer an object appears, the higher the numerical value given to its apparent magnitude, with a difference of 5 magnitudes corresponding to a brightness factor of exactly 100. Since an increase of 5 magnitudes corresponds to a decrease in brightness by a factor of exactly 100, each magnitude increase implies a decrease in brightness by the factor 5√100 ≈2.512. Inverting the above formula, a magnitude difference m1 − m2 = Δm implies a brightness factor of F2 F1 =100 Δ m 5 =100.4 Δ m ≈2.512 Δ m
8.
Albion (Blake)
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In the complex mythology of William Blake, Albion is the primeval man whose fall and division results in the Four Zoas, Urizen, Tharmas, Luvah/Orc and Urthona/Los. The name derives from the ancient and mythological name of Britain, in the mythical story of the founding of Britain, Albion was a Giant son of Poseidon, the Greek god of the sea. He was a contemporary of Heracles, who killed him, Albion founded a country on the island and ruled there. According to another myth, Noahs son Japhet had a son named Histion and their names were Francus, Romanus, Brittos and Alemannus, and the French, Roman, British and German people are descended from them. Brittos divided Britain into three kingdoms and gave each to one of his sons and they were Loegria, Scotland and Cambria. The division of the man is found in many mythic and mystic systems throughout the world, including Adam Kadmon in cabalism. The long, unfinished poem properly called Vala, or The Four Zoas expands the significance of the Zoas and it was formerly known as Glad Day, since it was assumed by Alexander Gilchrist to illustrate a quotation from Shakespeare. Blake also uses the name Albion in its meaning, as an ancient synonym for Britain, in his poem A Little Boy Lost in Songs of Experience. The poem tells about a boy who, using reason, realizes that humans are selfish. He asks the priest, Father, how can I love you / or any of my brothers more, / I love you like the bird that picks up crumbs around the door. The priest accuses the boy of blasphemy, and burns him in a holy place / where many had been burned before, Blake concludes the poem by asking, Are such things done on Albions shore. The Sons of Albion feature in the poem Jerusalem and they are 12, and are named as Hand, Hyle, Coban, Guantok, Peachey, Brereton, Slayd, Hutton, Scofield, Kox, Kotope, Bowen. These names are drawn from figures from Blakes 1803 sedition trial. The Daughters of Albion feature in Visions of the Daughters of Albion and they are named, not consistently though, in The Four Zoas and in Jerusalem, Gwendolen Ragan Sabrina Gonorill Mehetabel Cordella Boadicea/Gwiniverra Conwenna Estrild Gwinefrid Ignoge Cambel. Gwiniverra has replaced Boadicea, who is equated with Cambel. They are mostly drawn from Geoffrey of Monmouths Historia Regum Britanniae and John Miltons The History of Britain
9.
Vala, or The Four Zoas
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Vala, or The Four Zoas refers to one of the uncompleted prophetic books by the English poet William Blake, begun in 1797. The titular main characters of the book are the Four Zoas and it consists of nine books, referred to as nights. These outline the interactions of the Zoas, their fallen forms, Blake intended the book to be a summation of his mythic universe but, dissatisfied, he abandoned the effort in 1807, leaving it unfinished and unengraved. Blake began working on Vala, or The Death and Judgement of the Eternal Man and he continued to work on it throughout the decade but slowly lost confidence that he could complete the work as he was suffering from a deep state of depression. After 1800, he was able to work on it again, the actual manuscript of the poem was written on proof engravings of Night Thoughts. The lines were surrounded by large designs and there was around 2,000 lines in the edition of the poem and 4,000 in the second edition. Of Blakes revision to the work, he changed the last two nights. Vala was much larger than any of his previous works, europe a Prophecy was 265 lines and was printed on copperplates that measured 23 x 17 cm. The plates used to print Vala were 41 x 32 cm, the work also took far longer than his previous works, most of Blakes designs were completed within a year, but Vala took ten years for the whole process to be completed. A notebook was probably used to draft the poem or the designs of the work, one of the manuscript sheets was originally used to create a history of England that was abandoned by Blake in 1793. The work was never put into etching, and the manuscript was given to John Linnell, portions of the work were later used in his Jerusalem The Emanation of the Giant Albion. The poem is divided into nine nights, humanity is imprisoned by creation, and experience causes great pain, What is the price of Experience. Do men buy it for a song Or wisdom for a dance in the street, no it is bought with the price Of all that a man hath, his house his wife his children. Then fell the fires of Eternity with loud & shrill Sound of Loud Trumpet thundering along from heaven to heaven A mighty sound articulate, Awake, ye dead & come To Judgement from the four winds. The war of swords departed now The dark Religions are departed & sweet Science reigns Like many of Blakes works, Blake used these images as part of a general celebration of sex and sexuality. This emphasis on free sexuality occurs in The Marriage of Heaven and Hell, Visions of the Daughters of Albion, Blakes beliefs emphasised the need for sexual openness in relationships and the lack of jealousy. In Vala, the idea of jealousy is a central theme, between the various editions, the concept of the poem changes. The later edition was on a smaller scale, and it emphasises the concept of imprisonment found in the Book of Urizen
10.
Astronomical unit
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The astronomical unit is a unit of length, roughly the distance from Earth to the Sun. However, that varies as Earth orbits the Sun, from a maximum to a minimum. Originally conceived as the average of Earths aphelion and perihelion, it is now defined as exactly 149597870700 metres, the astronomical unit is used primarily as a convenient yardstick for measuring distances within the Solar System or around other stars. However, it is also a component in the definition of another unit of astronomical length. A variety of symbols and abbreviations have been in use for the astronomical unit. In a 1976 resolution, the International Astronomical Union used the symbol A for the astronomical unit, in 2006, the International Bureau of Weights and Measures recommended ua as the symbol for the unit. In 2012, the IAU, noting that various symbols are presently in use for the astronomical unit, in the 2014 revision of the SI Brochure, the BIPM used the unit symbol au. In ISO 80000-3, the symbol of the unit is ua. Earths orbit around the Sun is an ellipse, the semi-major axis of this ellipse is defined to be half of the straight line segment that joins the aphelion and perihelion. The centre of the sun lies on this line segment. In addition, it mapped out exactly the largest straight-line distance that Earth traverses over the course of a year, knowing Earths shift and a stars shift enabled the stars distance to be calculated. But all measurements are subject to some degree of error or uncertainty, improvements in precision have always been a key to improving astronomical understanding. Improving measurements were continually checked and cross-checked by means of our understanding of the laws of celestial mechanics, the expected positions and distances of objects at an established time are calculated from these laws, and assembled into a collection of data called an ephemeris. NASAs Jet Propulsion Laboratory provides one of several ephemeris computation services, in 1976, in order to establish a yet more precise measure for the astronomical unit, the IAU formally adopted a new definition. Equivalently, by definition, one AU is the radius of an unperturbed circular Newtonian orbit about the sun of a particle having infinitesimal mass. As with all measurements, these rely on measuring the time taken for photons to be reflected from an object. However, for precision the calculations require adjustment for such as the motions of the probe. In addition, the measurement of the time itself must be translated to a scale that accounts for relativistic time dilation
