In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting the rainbow of colors interspersed with spectral lines; each line indicates a particular chemical element or molecule, with the line strength indicating the abundance of that element. The strengths of the different spectral lines vary due to the temperature of the photosphere, although in some cases there are true abundance differences; the spectral class of a star is a short code summarizing the ionization state, giving an objective measure of the photosphere's temperature. Most stars are classified under the Morgan-Keenan system using the letters O, B, A, F, G, K, M, a sequence from the hottest to the coolest; each letter class is subdivided using a numeric digit with 0 being hottest and 9 being coolest. The sequence has been expanded with classes for other stars and star-like objects that do not fit in the classical system, such as class D for white dwarfs and classes S and C for carbon stars.
In the MK system, a luminosity class is added to the spectral class using Roman numerals. This is based on the width of certain absorption lines in the star's spectrum, which vary with the density of the atmosphere and so distinguish giant stars from dwarfs. Luminosity class 0 or Ia+ is used for hypergiants, class I for supergiants, class II for bright giants, class III for regular giants, class IV for sub-giants, class V for main-sequence stars, class sd for sub-dwarfs, class D for white dwarfs; the full spectral class for the Sun is G2V, indicating a main-sequence star with a temperature around 5,800 K. The conventional color description takes into account only the peak of the stellar spectrum. In actuality, stars radiate in all parts of the spectrum; because all spectral colors combined appear white, the actual apparent colors the human eye would observe are far lighter than the conventional color descriptions would suggest. This characteristic of'lightness' indicates that the simplified assignment of colors within the spectrum can be misleading.
Excluding color-contrast illusions in dim light, there are indigo, or violet stars. Red dwarfs are a deep shade of orange, brown dwarfs do not appear brown, but hypothetically would appear dim grey to a nearby observer; the modern classification system is known as the Morgan–Keenan classification. Each star is assigned a spectral class from the older Harvard spectral classification and a luminosity class using Roman numerals as explained below, forming the star's spectral type. Other modern stellar classification systems, such as the UBV system, are based on color indexes—the measured differences in three or more color magnitudes; those numbers are given labels such as "U-V" or "B-V", which represent the colors passed by two standard filters. The Harvard system is a one-dimensional classification scheme by astronomer Annie Jump Cannon, who re-ordered and simplified a prior alphabetical system. Stars are grouped according to their spectral characteristics by single letters of the alphabet, optionally with numeric subdivisions.
Main-sequence stars vary in surface temperature from 2,000 to 50,000 K, whereas more-evolved stars can have temperatures above 100,000 K. Physically, the classes indicate the temperature of the star's atmosphere and are listed from hottest to coldest; the spectral classes O through M, as well as other more specialized classes discussed are subdivided by Arabic numerals, where 0 denotes the hottest stars of a given class. For example, A0 denotes A9 denotes the coolest ones. Fractional numbers are allowed; the Sun is classified as G2. Conventional color descriptions are traditional in astronomy, represent colors relative to the mean color of an A class star, considered to be white; the apparent color descriptions are what the observer would see if trying to describe the stars under a dark sky without aid to the eye, or with binoculars. However, most stars in the sky, except the brightest ones, appear white or bluish white to the unaided eye because they are too dim for color vision to work. Red supergiants are cooler and redder than dwarfs of the same spectral type, stars with particular spectral features such as carbon stars may be far redder than any black body.
The fact that the Harvard classification of a star indicated its surface or photospheric temperature was not understood until after its development, though by the time the first Hertzsprung–Russell diagram was formulated, this was suspected to be true. In the 1920s, the Indian physicist Meghnad Saha derived a theory of ionization by extending well-known ideas in physical chemistry pertaining to the dissociation of molecules to the ionization of atoms. First he applied it to the solar chromosphere to stellar spectra. Harvard astronomer Cecilia Payne demonstrated that the O-B-A-F-G-K-M spectral sequence is a sequence in temperature; because the classification sequence predates our understanding that it is a temperature sequence, the placement of a spectrum into a given subtype, such as B3 or A7, depends upon estimates of the strengths of absorption features in stellar spectra. As a result, these subtypes are not evenly divided into any sort of mathematically representable intervals; the Yerkes spectral classification called the MKK system from the authors' initial
Spring is one of the four temperate seasons, following winter and preceding summer. There are various technical definitions of spring, but local usage of the term varies according to local climate and customs; when it is spring in the Northern Hemisphere, it is autumn in the Southern Hemisphere and vice versa. At the spring equinox and nights are twelve hours long, with day length increasing and night length decreasing as the season progresses. Spring and "springtime" refer to the season, to ideas of rebirth, renewal and regrowth. Subtropical and tropical areas have climates better described in terms of other seasons, e.g. dry or wet, monsoonal or cyclonic. Cultures may have local names for seasons which have little equivalence to the terms originating in Europe. Meteorologists define four seasons in many climatic areas: spring, summer and winter; these are demarcated by the values of their average temperatures on a monthly basis, with each season lasting three months. The three warmest months are by definition summer, the three coldest months are winter and the intervening gaps are spring and autumn.
Spring, when defined in this manner, can start on different dates in different regions. Thus, in the US and UK, spring months are March and May, while in New Zealand and Australia, spring conventionally begins on September 1 and ends November 30. Swedish meteorologists define the beginning of spring as the first occasion on which the average daytime temperature exceeds zero degrees Celsius for seven consecutive days, thus the date varies with latitude and elevation. In some cultures in the Northern Hemisphere, the astronomical vernal equinox is taken to mark the first day of spring, the summer solstice is taken as the first day of summer. In Persian culture the first day of spring is the first day of the first month which begins on 20 or 21 March. In other traditions, the equinox is taken as mid-spring. In the traditional Chinese calendar, the "spring" season consists of the days between Lichun, taking Chunfen as its midpoint ending at Lixia. According to the Celtic tradition, based on daylight and the strength of the noon sun, spring begins in early February and continues until early May.
The beginning of spring is not always determined by fixed calendar dates. The phenological or ecological definition of spring relates to biological indicators, such as the blossoming of a range of plant species, the activities of animals, the special smell of soil that has reached the temperature for micro flora to flourish; these indicators, along with the beginning of spring, vary according to the local climate and according to the specific weather of a particular year. Most ecologists divide the year into six seasons. In addition to spring, ecological reckoning identifies an earlier separate prevernal season between the hibernal and vernal seasons; this is a time when only the hardiest flowers like the crocus are in bloom, sometimes while there is still some snowcover on the ground. During early spring, the axis of the Earth is increasing its tilt relative to the Sun, the length of daylight increases for the relevant hemisphere; the hemisphere begins to warm causing new plant growth to "spring forth," giving the season its name.
Any snow begins to melt, swelling streams with runoff and any frosts become less severe. In climates that have no snow, rare frosts and ground temperatures increase more rapidly. Many flowering plants bloom at this time of year, in a long succession, sometimes beginning when snow is still on the ground and continuing into early summer. In snowless areas, "spring" may begin as early as February or August, heralded by the blooming of deciduous magnolias and quince. Many temperate areas have a dry spring, wet autumn, which brings about flowering in this season, more consistent with the need for water, as well as warmth. Subarctic areas may not experience "spring" at all until May. While spring is a result of the warmth caused by the changing orientation of the Earth's axis relative to the Sun, the weather in many parts of the world is affected by other, less predictable events; the rainfall in spring follows trends more related to longer cycles—such as the solar cycle—or events created by ocean currents and ocean temperatures—for example, the El Niño effect and the Southern Oscillation Index.
Unstable spring weather may occur more when warm air begins to invade from lower latitudes, while cold air is still pushing from the Polar regions. Flooding is most common in and near mountainous areas during this time of year, because of snow-melt, accelerated by warm rains. In North America, Tornado Alley is most active at this time of year since the Rocky Mountains prevent the surging hot and cold air masses from spreading eastward, instead force them into direct conflict. Besides tornadoes, supercell thunderstorms can produce dangerously large hail and high winds, for which a severe thunderstorm warning or tornado warning is issued. More so than in winter, the jet streams play an important role in unstable and severe Northern Hemisphere weather in springtime. In recent decades, season creep has been observed, which means that many phenological signs of spring are occurring earlier in many regions by around two days per decade. Spring in the Southern Hemisphere is different in several significant ways to that of the Northern Hemisphere
The Qixi Festival known as the Qiqiao Festival, is a Chinese traditional festival celebrating the annual meeting of the cowherd and the weaver girl in mythology. "Qi" means seven in Chinese, "Xi" means night in Chinese, so "Qixi" points out that the cowherd and the weaver maid meet with each other on the night of seventh day of the seventh month on the Chinese lunar calendar every year, so Qixi Festival is called Double Seventh Festival, Seventh Evening Festival or Night of Sevens. The festival originated from the romantic legend of two lovers, Zhinü and Niulang, who were the weaver girl and the cowherd, respectively; the tale of The Cowherd and the Weaver Girl has been celebrated in the Qixi Festival since the Han dynasty. The earliest-known reference to this famous myth dates back to over 2600 years ago, told in a poem from the Classic of Poetry; the Qixi festival inspired the Tanabata festival in Chilseok festival in Korea. Contemporarily, the Qixi Festival has been given the cultural meaning of Chinese Valentine's Day, because the love tale of the cowherd and the weaver maid has made the Qixi Festival become a symbol of love.
The general tale is a love story between Niulang. Their love was not allowed, thus they were banished to opposite sides of the Silver River. Once a year, on the 7th day of the 7th lunar month, a flock of magpies would form a bridge to reunite the lovers for one day. There are many variations of the story. During the Han dynasty, the practices were conducted in accordance to formal ceremonial state rituals. Over time, the festival activities included customs that the common people partook. Girls take part in worshiping the celestials during rituals, they go to the local temple to pray to Zhinü for wisdom. Paper items are burned as offerings. Girls may recite traditional prayers for dexterity in needlework, which symbolize the traditional talents of a good spouse. Divination could take place to determine possible dexterity in needlework, they make wishes for marrying someone who would be a loving husband. During the festival, girls make a display of their domestic skills. Traditionally, there would be contests amongst those who attempted to be the best in threading needles under low-light conditions like the glow of an ember or a half moon.
Today, girls sometimes gather toiletries in honor of the seven maidens. The festival held an importance for newlywed couples. Traditionally, they would worship the celestial couple for the last bid farewell to them; the celebration stood symbol for a happy marriage and showed that the married woman was treasured by her new family. On this day, the Chinese gaze to the sky to look for Vega and Altair shining in the Milky Way, while a third star forms a symbolic bridge between the two stars, it was said that if it rains on this day that it was caused by a river sweeping away the magpie bridge or that the rain is the tears of the separated couple. Based on the legend of a flock of magpies forming a bridge to reunite the couple, a pair of magpies came to symbolize conjugal happiness and faithfulness. Interactive Google doodles have been launched since the 2009 Qixi Festival to mark the occasion; the latest was launched for the 2018 Qixi Festival. Qixi Tribute Seven Sisters' Fruit Hard copy Ju. China, Korea: Culture and customs.
North Charleston: BookSurge. ISBN 1-4196-4893-4. Kiang, Heng Chye. Cities of aristocrats and bureaucrats: The development of medieval Chinese cityscapes. Singapore: Singapore University Press. ISBN 9971-69-223-6. Lai, Sufen Sophia. "Father in Heaven, Mother in Hell: Gender politics in the creation and transformation of Mulian's mother". Presence and presentation: Women in the Chinese literati tradition. New York: St. Martin's Press. ISBN 0-312-21054-X. Melton, J. Gordon. "The Double Seventh Festival". Religions of the world: A comprehensive encyclopedia of beliefs and practices. Santa Barbara: ABC-CLIO. ISBN 978-1-59884-203-6. Poon, Shuk-wah. Negotiating religion in modern China: State and common people in Guangzhou, 1900–1937. Hong Kong: Chinese University of Hong Kong. ISBN 978-962-996-421-4. Schomp, Virginia; the ancient Chinese. New York: Marshall Cavendish Benchmark. ISBN 0-7614-4216-2. Stepanchuk, Carol. Mooncakes and hungry ghosts: Festivals of China. San Francisco: China Books & Periodicals. ISBN 0-8351-2481-9.
Welch, Patricia Bjaaland. Chinese art: A guide to motifs and visual imagery. North Clarendon: Tuttle Publishing. ISBN 978-0-8048-3864-1. Zhao, Rongguang. A History of Food Culture in China. SCPG Publishing Corporation. ISBN 978-1-938368-16-5. Online Ladies on the ‘Night of Sevens’ Pleading for Skills. Dublin: Chester Beatty Library
Lyra is a small constellation. It is one of 48 listed by the 2nd century astronomer Ptolemy, is one of the 88 constellations recognized by the International Astronomical Union. Lyra was represented on star maps as a vulture or an eagle carrying a lyre, hence is sometimes referred to as Vultur Cadens or Aquila Cadens, respectively. Beginning at the north, Lyra is bordered by Draco, Hercules and Cygnus. Lyra is visible from the northern hemisphere from spring through autumn, nearly overhead, in temperate latitudes, during the summer months. From the southern hemisphere, it is visible low in the northern sky during the winter months. Vega, Lyra's brightest star, is one of the brightest stars in the night sky, forms a corner of the famed Summer Triangle asterism. Beta Lyrae is the prototype of a class of stars known as Beta Lyrae variables; these binary stars are so close to each other that they become egg-shaped and material flows from one to the other. Epsilon Lyrae, known informally as the Double Double, is a complex multiple star system.
Lyra hosts the Ring Nebula, the second-discovered and best-known planetary nebula. In Greek mythology, Lyra represents the lyre of Orpheus. Made by Hermes from a tortoise shell, given to Apollo as a bargain, it was said to be the first lyre produced. Orpheus's music was said to be so great that inanimate objects such as trees and rocks could be charmed. Joining Jason and the Argonauts, his music was able to quell the voices of the dangerous Sirens, who sang tempting songs to the Argonauts. At one point, Orpheus married a nymph. While fleeing from an attack by Aristaeus, she stepped on a snake. To reclaim her, Orpheus entered the Underworld. Hades relented and let Orpheus bring Eurydice back, on the condition that he never once look back until outside. Near the end, Orpheus faltered and looked back, causing Eurydice to be left in the Underworld forever. Orpheus spent the rest of his life strumming his lyre while wandering aimlessly through the land, rejecting all marriage offers from women. There are two competing myths relating to the death of Orpheus.
According to Eratosthenes, Orpheus failed to make a necessary sacrifice to Dionysus due to his regard for Apollo as the supreme deity instead. Dionysus sent his followers to rip Orpheus apart. Ovid tells a rather different story, saying that women, in retribution for Orpheus's rejection of marriage offers, ganged up and threw stones and spears. At first, his music charmed them as well, but their numbers and clamor overwhelmed his music and he was hit by the spears. Both myths state that his lyre was placed in the sky by Zeus, Orpheus' bones buried by the muses. Vega and its surrounding stars are treated as a constellation in other cultures; the area corresponding to Lyra was seen by the Arabs as a vulture or an eagle carrying a lyre, either enclosed in its wings, or in its beak. In Wales, Lyra is known as King Arthur's Harp, King David's harp; the Persian Hafiz called it the Lyre of Zurah. It has been called the Manger of Praesepe Salvatoris. In Australian Aboriginal astronomy, Lyra is known by the Boorong people in Victoria as the Malleefowl constellation.
Lyra was worshipped as an animal deity. Lyra is bordered by Vulpecula to the south, Hercules to the east, Draco to the north, Cygnus to the west. Covering 286.5 square degrees, it ranks 52nd of the 88 modern constellations in size. It appears prominently in the northern sky during the Northern Hemisphere's summer, the whole constellation is visible for at least part of the year to observers north of latitude 42°S, its main asterism consists of six stars, 73 stars in total are brighter than magnitude 6.5. The constellation's boundaries, as set by Eugène Delporte in 1930, are defined by a 17-sided polygon. In the equatorial coordinate system, the right ascension coordinates of these borders lie between 18h 14m and 19h 28m, while the declination coordinates are between +25.66° and +47.71°. The International Astronomical Union adopted the three-letter abbreviation "Lyr" for the constellation in 1922. German cartographer Johann Bayer used the Greek letters alpha through nu to label the most prominent stars in the constellation.
Flamsteed observed and labelled two stars each as delta, zeta and nu. He added pi and rho, not using xi and omicron as Bayer used hese letters to denote Cygnus and Hercules on his map; the brightest and far the most well-known star in the constellation is Vega, a main-sequence star of spectral type A0Va. Only 7.7 parsecs distant, is a Delta Scuti variable, varying between magnitudes −0.02 and 0.07 over 0.2 days. On average, it is the second-brightest star of a northern hemisphere and the fifth-brightest star in all, surpassed only by Arcturus, Alpha Centauri and Sirius. Vega was the pole star in the year 12,000 BCE, will again become the pole star around 14,000 CE. Vega is one of the most-magnificent of all stars, has been called "arguably the next most important star in the sky after the Sun". Vega was the first star other than the Sun to be photographed, as well as the first to have a clear spectrum recorded, showing absorption lines for the first time; the star was the first single main-sequence star other than the Sun to be known to emit X-rays, is surrounded by a circumstellar debris disk, similar to the Kuiper Belt.
Vega forms one corner of the famous Summer Triangle asterism. Vega forms one vertex of a much s
H. A. Rey
Hans Augusto Rey was a German-born American illustrator and author, known best for the Curious George series of children's picture books that he and his wife Margret Rey created from 1939 to 1966. Hans Augusto Reyersbach was born in Germany on September 16, 1898, as was his wife Margret. Hans and Margret were German Jews; the couple first met in Hamburg at Margret's sister's 16th birthday party. They met again in Brazil, where Hans was working as a salesman of bathtubs and Margret had gone to escape the rise of Nazism in Germany, they moved to Paris, France in August of that year. They lived in Montmartre and fled Paris in June 1940 on self-made bicycles, carrying the Curious George manuscript with them, he died three weeks before his 79th birthday on August 26, 1977 in Cambridge, United States of America. While in Paris, Hans's animal drawings came to the attention of a French publisher, who commissioned him to write a children's book; the result, Cecily G. and the Nine Monkeys, is little remembered, but one of its characters, an adorably impish monkey named Curious George, was such a success that the couple considered writing a book focused on him.
The outbreak of World War II interrupted their work. Being Jews, the Reys decided to flee Paris. Hans assembled two bicycles, they left the city just a few hours before it fell. Among the meager possessions they brought with them was the illustrated manuscript of Curious George; the Reys' odyssey took them to Bayonne, where they were issued life-saving visas signed by Vice-Consul Manuel Vieira Braga on June 20, 1940. They crossed the Spanish border. From there they returned to Brazil, where they had met five years earlier, but this time they continued to New York; the Reys escaped Europe carrying the manuscript to the first Curious George book, published in New York by Houghton Mifflin in 1941. Hans and Margret planned to use watercolor illustrations, but since they were responsible for the color separation, he changed these to the cartoon-like images that continue to be featured in each of the books. Curious George was an instant success, the Reys were commissioned to write more adventures of the mischievous monkey and his friend, the Man in the Yellow Hat.
They wrote seven stories in all, with Hans doing the illustrations and Margret working on the stories, though they both admitted to sharing the work and cooperating in every stage of development. At first, covers omitted Margret's name. In editions, this was changed, Margret now receives full credit for her role in developing the stories. Curious George Takes a Job was named to the Lewis Carroll Shelf Award list in 1960; the Reys relocated to Cambridge, Massachusetts during 1963, in a house near Harvard Square, lived there until Hans's death in 1977. In the 1990s, the Reys' friends founded a children's bookstore named Curious George & Friends, which operated in the Square until 2011. A new Curious George themed store opened in April 2012, The World's Only Curious George Store, which now stands in the same location as the original. Rey's interest in astronomy began during World War I and led to his desire to redraw constellation diagrams, which he found difficult to remember, so that they were more intuitive.
This led to the 1952 publication of The Stars: A New Way to See Them. His constellation diagrams were adopted and now appear in many astronomy guides, such as Donald H. Menzel's A Field Guide to the Stars and Planets; as of 2008 The Stars: A New Way to See Them, a simplified presentation for children called Find the Constellations, are still in print. A new edition of Find the Constellations was released in 2008, updated with modern fonts, the new status of Pluto, some more current measurements of planetary sizes and orbital radii; the University of Oregon holds H. A. Rey papers dated 1940 to 1961, dominated by correspondence between Rey and his American and British publishers; the de Grummond Children's Literature Collection in Hattiesburg, holds more than 300 boxes of Rey papers dated 1973 to 2002. Dr. Lena Y. de Grummond, a professor in the field of library science at the University of Southern Mississippi, contacted the Reys in 1966 about USM's new children's literature collection. H. A. and Margret donated a pair of sketches at the time.
When Margret Rey died in 1996, her will designated that the entire literary estate of the Reys be donated to the de Grummond Collection. Cecily G. and the Nine Monkeys Curious George Curious George Takes a Job Curious George Rides a Bike Curious George Gets a Medal Curious George Learns the Alphabet Curious George Goes to the Hospital Feed the Animals Find the Constellations Elizabite - Adventures of a Carnivorous Plant How Do You Get There? Pretzel The Stars: A New Way to See Them Where's My Baby? See the Circus Whiteblack the Penguin Sees the World Au Clair de la Lune and other French Nursery Songs Spotty Mary had a Little Lamb and other Nursery Songs Humpty Dumpty and other Mother Goose Songs Dem Andenken Christian Morgensterns 12 Lithographien zu seinem Werk, von Hans Reyersbach, signiert und mit Text in Bleistift HR 22 Die Sommerfrische: 10 Idyllen in Linol-Schnitt, von Hans Reyersbach, Berlin Grotesken - 12 Lithographien zu Christian Morgensterns Grotesken von Hans Reyersbach. Neue Folge.
400 Exemplare, Hamburg Kurt Enoch Verlag
The Southern Hemisphere is the half of Earth, south of the Equator. It contains parts of five continents, four oceans and most of the Pacific Islands in Oceania, its surface is 80.9% water, compared with 60.7% water in the case of the Northern Hemisphere, it contains 32.7% of Earth's land. Owing to the tilt of Earth's rotation relative to the Sun and the ecliptic plane, summer is from December to March and winter is from June to September. September 22 or 23 is the vernal equinox and March 20 or 21 is the autumnal equinox; the South Pole is in the center of the southern hemispherical region. Southern Hemisphere climates tend to be milder than those at similar latitudes in the Northern Hemisphere, except in the Antarctic, colder than the Arctic; this is because the Southern Hemisphere has more ocean and much less land. The differences are attributed to oceanic heat transfer and differing extents of greenhouse trapping. In the Southern Hemisphere the sun passes from east to west through the north, although north of the Tropic of Capricorn the mean sun can be directly overhead or due north at midday.
The Sun rotating through the north causes an apparent right-left trajectory through the sky unlike the left-right motion of the Sun when seen from the Northern Hemisphere as it passes through the southern sky. Sun-cast shadows turn anticlockwise throughout the day and sundials have the hours increasing in the anticlockwise direction. During solar eclipses viewed from a point to the south of the Tropic of Capricorn, the Moon moves from left to right on the disc of the Sun, while viewed from a point to the north of the Tropic of Cancer, the Moon moves from right to left during solar eclipses. Cyclones and tropical storms spin clockwise in the Southern Hemisphere due to the Coriolis effect; the southern temperate zone, a subsection of the Southern Hemisphere, is nearly all oceanic. This zone includes the southern tip of South Africa; the Sagittarius constellation that includes the galactic centre is a southern constellation and this, combined with clearer skies, makes for excellent viewing of the night sky from the Southern Hemisphere with brighter and more numerous stars.
Forests in the Southern Hemisphere have special features which set them apart from those in the Northern Hemisphere. Both Chile and Australia share, for example, unique beech species or Nothofagus, New Zealand has members of the related genera Lophozonia and Fuscospora; the eucalyptus is native to Australia but is now planted in Southern Africa and Latin America for pulp production and biofuel uses. 800 million humans live in the Southern Hemisphere, representing only 10–12% of the total global human population of 7.3 billion. Of those 800 million people, 200 million live in Brazil, the largest country by land area in the Southern Hemisphere, while 141 million live on the island of Java, the most populous island in the world; the most populous nation in the Southern Hemisphere is Indonesia, with 261 million people. Portuguese is the most spoken language in the Southern Hemisphere, followed by Javanese; the largest metropolitan areas in the Southern Hemisphere are São Paulo, Buenos Aires, Rio de Janeiro and Sydney.
The most important financial and commercial centers in the Southern Hemisphere are São Paulo, where the Bovespa Index is headquartered, along with Sydney, home to the Australian Securities Exchange, home to the Johannesburg Stock Exchange and Buenos Aires, headquarters of the Buenos Aires Stock Exchange, the oldest stock market in the Southern Hemisphere. Among the most developed nations in the Southern Hemisphere are Australia, with a nominal GDP per capita of US$51,850 and a Human Development Index of 0.939, the second highest in the world as of 2016. New Zealand is well developed, with a nominal GDP per capita of US$38,385 and a Human Development Index of 0.915, putting it at #13 in the world in 2016. The least developed nations in the Southern Hemisphere cluster in Africa and Oceania, with Burundi and Mozambique at the lowest ends of the Human Development Index, at 0.404 and 0.418 respectively. The nominal GDP per capitas of these two countries don't go above US$550 per capita, a tiny fraction of the incomes enjoyed by Australians and New Zealanders.
The most widespread religions in the Southern Hemisphere are Christianity in South America, southern Africa and Australia/New Zealand, followed by Islam in most of the islands of Indonesia and in parts of southeastern Africa, Hinduism, concentrated on the island of Bali and neighboring islands. The oldest continuously inhabited city in the Southern Hemisphere is Bogor, in western Java, founded in 669 CE. Ancient texts from the Hindu kingdoms prevalent in the area definitively record 669 CE as the year when Bogor was founded. However, there is some evidence that Zanzibar, an ancient port with around 200,000 inhabitants on
Aquila is a constellation on the celestial equator. Its name is Latin for'eagle' and it represents the bird that carried Zeus/Jupiter's thunderbolts in Greco-Roman mythology, its brightest star, Altair, is one vertex of the Summer Triangle asterism. The constellation is best seen in the northern summer; because of this location, many clusters and nebulae are found within its borders, but they are dim and galaxies are few. Aquila was one of the 48 constellations described by the second-century astronomer Ptolemy, it had been earlier mentioned by Eudoxus in the fourth century BC and Aratus in the third century BC. It is now one of the 88 constellations defined by the International Astronomical Union; the constellation was known as Vultur volans to the Romans, not to be confused with Vultur cadens, their name for Lyra. It is held to represent the eagle which held Zeus's/Jupiter's thunderbolts in Greco-Roman mythology. Aquila is associated with the eagle that kidnapped Ganymede, a son of one of the kings of Troy, to Mount Olympus to serve as cup-bearer to the gods.
Ptolemy catalogued 19 stars jointly in this constellation and in the now obsolete constellation of Antinous, named in the reign of the emperor Hadrian, but sometimes erroneously attributed to Tycho Brahe, who catalogued 12 stars in Aquila and seven in Antinous. Hevelius determined 23 stars in 19 in the second; the Greek Aquila is based on the Babylonian constellation of the Eagle, located in the same area as the Greek constellation. Aquila, which lies in the Milky Way, contains many rich starfields and has been the location of many novae. Α Aql is the brightest star in this constellation and one of the closest naked-eye stars to Earth at a distance of 17 light-years. Its name comes from the Arabic phrase al-nasr al-tair, meaning "the flying eagle". Altair has a magnitude of 0.76. Β Aql is a yellow-hued star of 45 light-years from Earth. Its name comes from the Arabic phrase shahin-i tarazu, meaning "the balance". Γ Aql is an orange-hued giant star of 460 light-years from Earth. Its name, like that of Alshain, comes from the Arabic for "the balance".
Ζ Aql is a blue-white-hued star of 83 light-years from Earth. Η Aql is 1200 light-years from Earth. Among the brightest Cepheid variable stars, it has a minimum magnitude of 4.4 and a maximum magnitude of 3.5 with a period of 7.2 days. 15 Aql is an optical double star. The primary is an orange-hued giant of 325 light-years from Earth; the secondary is a purple-hued star of 550 light-years from Earth. The pair is resolved in small amateur telescopes. 57 Aql is a binary star. The primary is a blue-hued star of magnitude 5.7 and the secondary is a white star of magnitude 6.5. The system is 350 light-years from Earth. R Aql is a red-hued giant star 690 light-years from Earth, it is a Mira variable with a minimum magnitude of 12.0, a maximum magnitude of 6.0, a period around 9 months. It has a diameter of 400 D☉. FF Aql is a yellow-white-hued supergiant star, 2500 light-years from Earth, it is a Cepheid variable star with a minimum magnitude of 5.7, a maximum magnitude of 5.2, a period of 4.5 days. Ρ Aql moved across the border into neighboring Delphinus in 1992.
Two major novae have been observed in Aquila. Three interesting planetary nebulae lie in Aquila: NGC 6804 shows a small but bright ring. NGC 6781 bears some resemblance with the Owl Nebula in Ursa Major. NGC 6751 known as the Glowing Eye, is a planetary nebula. More deep-sky objects: NGC 6709 is a loose open cluster containing 40 stars, which range in magnitude from 9 to 11, it is about 3000 light-years from Earth. It is about 9100 light-years from Earth. NGC 6709 appears in a rich Milky Way star field and is classified as a Shapley class d and Trumpler class III 2 m cluster; these designations mean that it does not have many stars, is loose, does not show greater concentration at the center, has a moderate range of star magnitudes. NGC 6755 is an open cluster of 7.5 m. NGC 6760 is a globular cluster of 9.1 m. NGC 6749 is an open cluster. NGC 6778 is a planetary nebula. NGC 6741 is a planetary nebula. NGC 6772 is a planetary nebula. Aquila holds some extragalactic objects. One of them is what may be the largest single mass concentration of galaxies in the Universe known, the Hercules–Corona Borealis Great Wall.
It was discovered in November 2013, has the size of 10 billion light years. It is the most massive structure in the Universe known. NASA's Pioneer 11 space probe, which flew by Jupiter and Saturn in the 1970s, is expected to pass near the star Lambda Aquilae in about 4 million years. In illustrations of Aquila that represent it as an eagle, a nearly straight line of three stars symbolizes part of the wings; the center and brightest of these three stars is Altair. The tips of the wings extend further to the southeast and northwest; the head of the eagle stretches off to the southwest. According to Gavin White, the Babylonian Eagle carried the constellation called the Dead Man in its talons; the author draws a comparison to the classical stories of Antinous and Ganymede. In classical Greek mythology, Aquila was identified as Αετός Δίας, the eagle that