Tết, Vietnamese New Year, Vietnamese Lunar New Year or Tet Holiday, is the most important celebration in Vietnamese culture. The word is a shortened form of Tết Nguyên Đán, Sino-Vietnamese for "Feast of the First Morning of the First Day". Tết celebrates the arrival of spring based on the Vietnamese calendar, which has the date falling in January or February in the Gregorian calendar. Vietnamese people celebrate the Lunar New Year annually, based on a lunisolar calendar. Tết is celebrated on the same day as Chinese New Year, except when the one-hour time difference between Vietnam and China results in new moon occurring on different days, it takes place from the first day of the first month of the Vietnamese calendar until at least the third day. Many Vietnamese prepare for Tết by cleaning the house; these foods include bánh chưng, bánh dày, dried young bamboo soup, giò, sticky rice. Many customs are practiced during Tết, such as visiting a person's house on the first day of the new year, ancestor worship, wishing New Year's greetings, giving lucky money to children and elderly people, opening a shop.
Tết is an occasion for pilgrims and family reunions. They start forgetting about the troubles of the past hope for a better upcoming year, they consider Tết to be the first day of spring, the festival is called Hội xuân. Vietnamese people return to their families during Tết; some return to visit the graves of their ancestors in their homeland. They clean the graves of their family as a sign of respect. Although Tết is a national holiday among all Vietnamese, each region and religion has its own customs. Tết in the three Vietnamese regions can be divided into three periods, known as Tất Niên, Giao Thừa, Tân Niên, representing the preparation before Tết, the eve of Tết, the days of and following Tết, respectively; the first day of Tết is reserved for the nuclear family. Children receive a red envelope containing money from their elders; this tradition is called mừng tuổi in the lì xì in the south. Children wear their new clothes and give their elders the traditional Tết greetings before receiving the money.
Since the Vietnamese believe that the first visitor a family receives in the year determines their fortune for the entire year, people never enter any house on the first day without being invited first. The act of being the first person to enter a house on Tết is called xông đất, xông nhà or đạp đất, one of the most important rituals during Tết. According to Vietnamese tradition, if good things come to the family on the first day of the lunar New Year, the entire following year will be full of blessings. A person of good temper and success will be the lucky sign for the host family and be invited first into the house. However, just to be safe, the owner of the house will leave the house a few minutes before midnight and come back just as the clock strikes midnight to prevent anyone else entering the house first who might bring any unfortunate events in the new year to the household. Sweeping during Tết is taboo or xui, since it symbolizes sweeping the luck away, it is taboo for anyone who experienced a recent loss of a family member to visit anyone else during Tết.
During subsequent days, people visit friends. Traditionally but not the second day of Tết is reserved for friends, while the third day is for teachers, who command respect in Vietnam. Local Buddhist temples are popular spots as people like to give donations and to get their fortunes told during Tết. Children are free to spend their new money on toys or on gambling games such as bầu cua cá cọp, which can be found in the streets. Prosperous families can pay for dragon dancers to perform at their house. Public performances are given for everyone to watch; these celebrations can last from a day up to the entire week, the New Year is filled with people in the streets trying to make as much noise as possible using firecrackers, bells and anything they can think of to ward off evil spirits. This parade will include different masks, dancers hidden under the guise of what is known as the Mua Lan or Lion Dancing; the Lan is an animal between a lion and a dragon, is the symbol of strength in the Vietnamese culture, used to scare away evil spirits.
After the parade and friends come together to have a feast of traditional Vietnamese dishes, share the happiness and joy of the New Year with one another. This is the time when the elders will hand out red envelopes with money to the children for good luck in exchange for Tết greetings, it is tradition to pay off your debts before the Lunar New Year for some Vietnamese families. Traditionally, each family displays cây nêu, an artificial New Year tree consisting of a bamboo pole 5 to 6 m long; the top end is decorated with many objects, depending on the locality, including good luck charms, origami fish, cactus branches, etc. At Tết, every house is decorated by Yellow Apricot blossoms in the central and southern parts of Vietnam. In the north, some people decorate their house with a plum blossoms (also called hoa mai in Vietnamese, but referring to a different species from
Vesak known as Wesak, Buddha Purnima and Buddha Day, is a holiday traditionally observed by Buddhists and some Hindus on different days in India, Sri Lanka, Tibet, Bhutan, Singapore, Cambodia, Malaysia, Myanmar and the Philippines and in China, South Korea, North Korea and Vietnam as "Buddha's Birthday" as well as in other parts of the world. The festival commemorates the birth and death of Gautama Buddha in the Theravada or southern tradition; the decision to agree to celebrate Wesākha as the Buddha’s birthday was formalized at the first conference of the World Fellowship of Buddhists held in Sri Lanka in 1950, although festivals at this time in the Buddhist world are a centuries-old tradition. The resolution, adopted at the World Conference reads as follows: That this Conference of the World Fellowship of Buddhists, while recording its appreciation of the gracious act of His Majesty, the Maharaja of Nepal in making the full-moon day of Vesak a Public Holiday in Nepal, earnestly requests the Heads of Governments of all countries in which large or small number of Buddhists are to be found, to take steps to make the full-moon day in the month of May a Public Holiday in honour of the Buddha, universally acclaimed as one of the greatest benefactors of Humanity.
On Vesākha Day, Buddhists all over the world commemorate events of significance to Buddhists of all traditions: The birth and the passing away of Gautama Buddha. As Buddhism spread from India it was assimilated into many foreign cultures, Vesākha is celebrated in many different ways all over the world. In India, Vaishakh Purnima day is known as Buddha Jayanti day and has been traditionally accepted as Buddha's birth day. In 1999, the United Nations resolved to internationally observe the day of Vesak at its headquarters and offices; the name of the observance is derived from the Pali term vesākha or Sanskrit vaiśākha, the name of the lunar month used in ancient India falling in April–May. In Mahayana Buddhist traditions, the holiday is known by its Sanskrit name and derived variants of it. Local renditions of the name vary by language, including: Assamese: বুদ্ধ পূর্ণিমা Buddho Purnima Bengali: বুদ্ধ পূর্ণিমা Buddho Purnima, বুদ্ধ জয়ন্তী Buddho Joyonti Dzongkha: སྟོན་པའི་དུས་ཆེན་༥ འཛོམས་ Dhüchen Nga Zom Burmese: ကဆုန်လပြည့် ဗုဒ္ဓနေ့ "Full Moon Day of Kason" Chinese: 佛陀誕辰紀念日.
Some countries celebrated Vesākha on the 1st, others celebrated the holiday on the 31st because of a different local lunar observance. The difference manifests in the observance of other Buddhist holidays, which are traditionally observed at the local full moon. In 2012, Vesak was observed on 28 April in Hong Kong and Taiwan, on 5 May in Sri Lanka, on 6 May in India and Bangladesh, on 28 May in South Korea and on 4 June in Thailand.. In 2014, Vesak is celebrated on 13 May in Myanmar and Thailand while it is observed on 15 May in Indonesia. On Vesākha, devout Buddhists and followers alike assemble in their various temples before dawn for the ceremonial and honorable hoisting of the Buddhist flag and the singing of hymns in praise of the holy triple gem: The Buddha, The Dharma, The Sangha. Devotees may bring simple offerings of flowers and joss-sticks to lay at the feet of their teacher; these symbolic offerings are to remind followers that just as the beautiful flowers would wither away after a short while and the candles and joss-sticks would soon burn out, so too is life subject to decay and destruction.
Devotees are enjoined to make a special effort to refrain from killing of any kind. They are encouraged to partake of vegetarian food for the day. In some countries, notably Sri Lanka, two days are set aside for the celebration of Vesākha and all liquor shops and slaughter houses are closed by government decree during the two days. Birds and animals are released by the thousands in what is known as a'symbolic act of liberation' of giving freedom to those who are in captivity, imprisoned, or tortured against their will; some devout Buddhists will wear a simple white dress and spend the whole day in temples with renewed determination
Scotland is a country, part of the United Kingdom. Sharing a border with England to the southeast, Scotland is otherwise surrounded by the Atlantic Ocean to the north and west, by the North Sea to the northeast and by the Irish Sea to the south. In addition to the mainland, situated on the northern third of the island of Great Britain, Scotland has over 790 islands, including the Northern Isles and the Hebrides; the Kingdom of Scotland emerged as an independent sovereign state in the Early Middle Ages and continued to exist until 1707. By inheritance in 1603, James VI, King of Scots, became King of England and King of Ireland, thus forming a personal union of the three kingdoms. Scotland subsequently entered into a political union with the Kingdom of England on 1 May 1707 to create the new Kingdom of Great Britain; the union created a new Parliament of Great Britain, which succeeded both the Parliament of Scotland and the Parliament of England. In 1801, the Kingdom of Great Britain and Kingdom of Ireland enacted a political union to create a United Kingdom.
The majority of Ireland subsequently seceded from the UK in 1922. Within Scotland, the monarchy of the United Kingdom has continued to use a variety of styles and other royal symbols of statehood specific to the pre-union Kingdom of Scotland; the legal system within Scotland has remained separate from those of England and Wales and Northern Ireland. The continued existence of legal, educational and other institutions distinct from those in the remainder of the UK have all contributed to the continuation of Scottish culture and national identity since the 1707 union with England; the Scottish Parliament, a unicameral legislature comprising 129 members, was established in 1999 and has authority over those areas of domestic policy which have been devolved by the United Kingdom Parliament. The head of the Scottish Government, the executive of the devolved legislature, is the First Minister of Scotland. Scotland is represented in the UK House of Commons by 59 MPs and in the European Parliament by 6 MEPs.
Scotland is a member of the British–Irish Council, sends five members of the Scottish Parliament to the British–Irish Parliamentary Assembly. Scotland is divided into councils. Glasgow City is the largest subdivision in Scotland in terms of population, with Highland being the largest in terms of area. "Scotland" comes from the Latin name for the Gaels. From the ninth century, the meaning of Scotia shifted to designate Gaelic Scotland and by the eleventh century the name was being used to refer to the core territory of the Kingdom of Alba in what is now east-central Scotland; the use of the words Scots and Scotland to encompass most of what is now Scotland became common in the Late Middle Ages, as the Kingdom of Alba expanded and came to encompass various peoples of diverse origins. Repeated glaciations, which covered the entire land mass of modern Scotland, destroyed any traces of human habitation that may have existed before the Mesolithic period, it is believed the first post-glacial groups of hunter-gatherers arrived in Scotland around 12,800 years ago, as the ice sheet retreated after the last glaciation.
At the time, Scotland was covered in forests, had more bog-land, the main form of transport was by water. These settlers began building the first known permanent houses on Scottish soil around 9,500 years ago, the first villages around 6,000 years ago; the well-preserved village of Skara Brae on the mainland of Orkney dates from this period. Neolithic habitation and ritual sites are common and well preserved in the Northern Isles and Western Isles, where a lack of trees led to most structures being built of local stone. Evidence of sophisticated pre-Christian belief systems is demonstrated by sites such as the Callanish Stones on Lewis and the Maes Howe on Orkney, which were built in the third millennium BCE; the first written reference to Scotland was in 320 BC by Greek sailor Pytheas, who called the northern tip of Britain "Orcas", the source of the name of the Orkney islands. During the first millennium BCE, the society changed to a chiefdom model, as consolidation of settlement led to the concentration of wealth and underground stores of surplus food.
The first Roman incursion into Scotland occurred in 79 AD. After the Roman victory, Roman forts were set along the Gask Ridge close to the Highland line, but by three years after the battle, the Roman armies had withdrawn to the Southern Uplands; the Romans erected Hadrian's Wall in northern England and the Limes Britannicus became the northern border of the Roman Empire. The Roman influence on the southern part of the country was considerable, they introduced Christianity to Scotland. Beginning in the sixth century, the area, now Scotland was divided into three areas: Pictland, a patchwork of small lordships in central Scotland; these societies were based on the family unit and had sharp divisions in wealth, although the vast majority were poor and worked full-time in subsistence agriculture. The Picts kept slaves through the ninth century. Gaelic influence over Pictland and Northumbria was facilitated by the large number of Gaelic-speaking clerics working as missionaries. Operating in the sixth ce
The Mid-Autumn Festival is a harvest festival celebrated notably by the Chinese and Vietnamese people. The festival is held on the 15th day of the 8th month of the lunar calendar with full moon at night, corresponding to late September to early October of the Gregorian calendar with a full moon at night. Mooncakes, a rich pastry filled with sweet bean paste or lotus seed paste are traditionally eaten during the festival; the Mid-Autumn Festival is known by other names, such as: Moon Festival or Harvest Moon Festival, because of the celebration's association with the full moon on this night, as well as the traditions of moon worship and moon gazing. Jūng-chāu Jit, official name in Cantonese. Tết Trung Thu, official name in Vietnamese. Zhōngqiū Jié, the official name in Mandarin. Lantern Festival, a term sometimes used in Singapore and Indonesia, not to be confused with the Lantern Festival in China that occurs on the 15th day of the first month of the Chinese calendar. Reunion Festival, in earlier times, a woman in China took this occasion to visit her parents before returning to celebrate with her husband and his parents.
Children's Festival, in Vietnam, because of the emphasis on the celebration of children. The festival celebrates three fundamental concepts that are connected: Gathering, such as family and friends coming together, or harvesting crops for the festival. It's said the moon is roundest on this day which means family reunion; this is the main reason why the festival is thought to be important. Thanksgiving, to give thanks for the harvest, or for harmonious unions Praying, such as for babies, a spouse, longevity, or for a good futureTraditions and myths surrounding the festival are formed around these concepts, although traditions have changed over time due to changes in technology, economy and religion. It's about well being together; the Chinese have celebrated the harvest during the autumn full moon since the Shang dynasty. For the Baiyue peoples, the harvest time commemorated the dragon; the celebration as a festival only started to gain popularity during the early Tang dynasty. One legend explains that Emperor Xuanzong of Tang started to hold formal celebrations in his palace after having explored the Moon-Palace.
The term mid-autumn first appeared in Rites of Zhou, a written collection of rituals of the Western Zhou dynasty. Empress Dowager Cixi enjoyed celebrating Mid-Autumn Festival so much that she would spend the period between the thirteenth and seventeenth day of the eighth month staging elaborate rituals. An important part of the festival celebration is moon worship; the ancient Chinese believed in rejuvenation being associated with the moon and water, connected this concept to the menstruation of women, calling it "monthly water". The Zhuang people, for example, have an ancient fable saying the sun and moon are a couple and the stars are their children, when the moon is pregnant, it becomes round, becomes crescent after giving birth to a child; these beliefs made it popular among women to give offerings to the moon on this evening. In some areas of China, there are still customs in which "men do not worship the moon and the women do not offer sacrifices to the kitchen gods."Offerings are made to a more well-known lunar deity, Chang'e, known as the Moon Goddess of Immortality.
The myths associated with Chang'e explain the origin of moon worship during this day. One version of the story is as follows, as described in Lihui Yang's Handbook of Chinese Mythology: In the ancient past, there was a hero named Hou Yi, excellent at archery, his wife was Chang'e. One year, the ten suns rose in the sky together. Yi left only one to provide light. An immortal sent him the elixir of immortality. Yi did not want to leave Chang'e and be immortal without her, so he let Chang'e keep the elixir, but Pang Meng, one of his apprentices, knew this secret. So, on the fifteenth of August in the lunar calendar, when Yi went hunting, Peng Meng broke into Yi's house and forced Chang'e to give the elixir to him. Chang'e refused to do so. Instead, she flew into the sky. Since she loved much her husband and hoped to live nearby, she chose the moon for her residence; when Yi came back and learned what had happened, he felt so sad that he displayed the fruits and cakes Chang'e liked in the yard and gave sacrifices to his wife.
People soon learned about these activities, since they were sympathetic to Chang'e they participated in these sacrifices with Yi. Handbook of Chinese Mythology describes an alternate common version of the myth: After the hero Houyi shot down nine of the ten suns, he was pronounced king by the thankful people. However, he soon became a tyrannical ruler. In order to live long without death, he asked for the elixir from Xiwangmu, but his wife, Chang'e, stole it on the fifteenth of August because she did not want the cruel king to live long and hurt more people. She took the magic potion to prevent her husband from becoming immortal. Houyi was so angry when discovered that Chang'e took the elixir, he shot at his wife as she flew toward the moon, though he missed. Chang' e became the spirit of the moon. Houyi died. Thereafter, people offer a sacrifice to Chang'e on every lunar fifteenth of August to commemorate Chang'e's action; the festival was a time to enjoy the successful reaping of rice and wheat with food offerings made in honor of the moon.
Today, it is still an occasion for ou
In astronomy, the new moon is the first lunar phase, when the Moon and Sun have the same ecliptic longitude. At this phase, the lunar disk is not visible to the unaided eye, except when silhouetted during a solar eclipse. Daylight outshines the earthlight; the actual phase is a thin crescent. The original meaning of the term new moon, still sometimes used in non-astronomical contexts, was the first visible crescent of the Moon, after conjunction with the Sun; this crescent moon is visible when low above the western horizon shortly after sunset and before moonset. A lunation or synodic month is the average time from one new moon to the next. In the J2000.0 epoch, the average length of a lunation is 29.530588 days. However, the length of any one synodic month can vary from 29.26 to 29.80 days due to the perturbing effects of the Sun's gravity on the Moon's eccentric orbit. In a lunar calendar, each month corresponds to a lunation; each lunar cycle can be assigned a unique lunation number to identify it.
The length of a lunation is about 29.53 days. Its precise duration is linked to many phenomena in nature, such as the variation between spring and neap tides. An approximate formula to compute the mean moments of new moon for successive months is: d = 5.597661 + 29.5305888610 × N + × N 2 where N is an integer, starting with 0 for the first new moon in the year 2000, and, incremented by 1 for each successive synodic month. To obtain this moment expressed in Universal Time, add the result of following approximate correction to the result d obtained above: − 0.000739 − × N 2 daysPeriodic perturbations change the time of true conjunction from these mean values. For all new moons between 1601 and 2401, the maximum difference is 0.592 days = 14h13m in either direction. The duration of a lunation varies in this period between 29.272 and 29.833 days, i.e. −0.259d = 6h12m shorter, or +0.302d = 7h15m longer than average. This range is smaller than the difference between mean and true conjunction, because during one lunation the periodic terms cannot all change to their maximum opposite value.
See the article on the full moon cycle for a simple method to compute the moment of new moon more accurately. The long-term error of the formula is approximately: 1 cy2 seconds in TT, 11 cy2 seconds in UT The moment of mean conjunction can be computed from an expression for the mean ecliptical longitude of the Moon minus the mean ecliptical longitude of the Sun. Jean Meeus gave formulae to compute this in his Astronomical Formulae for Calculators based on the ephemerides of Brown and Newcomb; these are now outdated: Chapront et al. published improved parameters. Meeus's formula uses a fractional variable to allow computation of the four main phases, uses a second variable for the secular terms. For the convenience of the reader, the formula given above is based on Chapront's latest parameters and expressed with a single integer variable, the following additional terms have been added: constant term: Like Meeus, apply the constant terms of the aberration of light for the Sun's motion and light-time correction for the Moon to obtain the apparent difference in ecliptical longitudes:Sun: +20.496" Moon: −0.704" Correction in conjunction: −0.000451 daysFor UT: at 1 January 2000, ΔT was +63.83 s.
The term includes a tidal contribution of 0.5×. The most current estimate from Lunar Laser Ranging for the acceleration is:"/cy2. Therefore, the new quadratic term of D is = -6.8498"T2. Indeed, the polynomial provided by Chapront et alii provides the same value; this translates to a correction of +14.622×10−12N2 days to the time of conjunction. For UT: analysis of historical observations shows that ΔT has a long-term increase of +31 s/cy2. Converted to days and lunations, the correction from ET to UT becomes:−235×10−12N2 days; the theoretical tidal contribution to ΔT is about +42 s/cy2 the smaller observed value is thought to be due to changes in the shape of the Earth. Because the discrepancy is not explained, uncertainty of our prediction of UT may be as large as the difference between these values: 11 s/cy2; the error in the position of the Moon itself is only maybe 0.5"/cy2, or (because the apparent mean angular velocit
The full moon is the lunar phase when the Moon appears illuminated from Earth's perspective. This occurs when Earth is located between the Moon; this means that the lunar hemisphere facing Earth – the near side – is sunlit and appears as a circular disk, while the far side is dark. The full moon occurs once every month; when the Moon moves into Earth's shadow, a lunar eclipse occurs, during which all or part of the Moon's face may appear reddish due to the Rayleigh scattering of blue wavelengths and the refraction of sunlight through Earth's atmosphere. Lunar eclipses happen only during full moon and around points on its orbit where the satellite may pass through the planet's shadow. A lunar eclipse does not occur every month because the Moon's orbit is inclined 5.14° with respect to the ecliptic plane of Earth. Lunar eclipses happen only. Therefore, a lunar eclipse occurs every 6 months and 2 weeks before or after a solar eclipse, which occurs during new moon around the opposite node; the interval period between a new or full moon and the next same phase, a synodic month, averages about 29.53 days.
Therefore, in those lunar calendars in which each month begins on the day of the new moon, the full moon falls on either the 14th or 15th day of the lunar month. Because a calendar month consists of a whole number of days, a lunar month may be either 29 or 30 days long. A full moon is thought of as an event of a full night's duration; this is somewhat misleading because its phase seen from Earth continuously wanes. Its maximum illumination occurs at the moment waxing. For any given location, about half of these maximum full moons may be visible, while the other half occurs during the day, when the full moon is below the horizon. Many almanacs list full moons not only by date, but by their exact time in Coordinated Universal Time. Typical monthly calendars that include lunar phases may be offset by one day when used in a different time zone. Full moon is a suboptimal time for astronomical observation of the Moon because shadows vanish, it is a poor time for other observations because the bright sunlight reflected by the Moon, amplified by the opposition surge outshines many stars.
On 12 December 2008, the full moon occurred closer to the Earth than it had been at any time for the previous 15 years, called a supermoon. On 19 March 2011, another full supermoon occurred, closer to the Earth than at any time for the previous 18 years. On 14 November 2016, a full supermoon occurred closer to the Earth than at any time for the previous 68 years; the date and approximate time of a specific full moon can be calculated from the following equation: d = 20.362000 + 29.530588861 × N + 102.026 × 10 − 12 × N 2 where d is the number of days since 1 January 2000 00:00:00 in the Terrestrial Time scale used in astronomical ephemerides. The true time of a full moon may differ from this approximation by up to about 14.5 hours as a result of the non-circularity of the moon's orbit. See New moon for an explanation of the formula and its parameters; the age and apparent size of the full moon vary in a cycle of just under 14 synodic months, referred to as a full moon cycle. Full moons are traditionally associated with temporal insomnia and various "magical phenomena" such as lycanthropy.
Psychologists, have found that there is no strong evidence for effects on human behavior around the time of a full moon. They find that studies are not consistent, with some showing a positive effect and others showing a negative effect. In one instance, the 23 December 2000 issue of the British Medical Journal published two studies on dog bite admission to hospitals in England and Australia; the study of the Bradford Royal Infirmary found that dog bites were twice as common during a full moon, whereas the study conducted by the public hospitals in Australia found that they were less likely. Month names are names of moons in lunisolar calendars. Since the introduction of the solar Julian calendar in the Roman Empire, the Gregorian calendar worldwide, people no longer perceive month names as "moon" names; the traditional Old English month names were equated with the names of the Julian calendar from an early time. Some full moons have developed new names in modern times, e.g. the blue moon, the names "harvest moon" and "hunter's moon" for the full moons of autumn.
Lunar eclipses only happen during a full moon and cast a reddish tint over the face of the moon. This has been called a blood moon in popular culture; the "harvest moon" and "hunter's moon" are traditional terms for the full moons occurri
The Moon is an astronomical body that orbits planet Earth and is Earth's only permanent natural satellite. It is the fifth-largest natural satellite in the Solar System, the largest among planetary satellites relative to the size of the planet that it orbits; the Moon is after Jupiter's satellite Io the second-densest satellite in the Solar System among those whose densities are known. The Moon is thought to have formed not long after Earth; the most accepted explanation is that the Moon formed from the debris left over after a giant impact between Earth and a Mars-sized body called Theia. The Moon is in synchronous rotation with Earth, thus always shows the same side to Earth, the near side; the near side is marked by dark volcanic maria that fill the spaces between the bright ancient crustal highlands and the prominent impact craters. After the Sun, the Moon is the second-brightest visible celestial object in Earth's sky, its surface is dark, although compared to the night sky it appears bright, with a reflectance just higher than that of worn asphalt.
Its gravitational influence produces the ocean tides, body tides, the slight lengthening of the day. The Moon's average orbital distance is 1.28 light-seconds. This is about thirty times the diameter of Earth; the Moon's apparent size in the sky is the same as that of the Sun, since the star is about 400 times the lunar distance and diameter. Therefore, the Moon covers the Sun nearly during a total solar eclipse; this matching of apparent visual size will not continue in the far future because the Moon's distance from Earth is increasing. The Moon was first reached in September 1959 by an unmanned spacecraft; the United States' NASA Apollo program achieved the only manned lunar missions to date, beginning with the first manned orbital mission by Apollo 8 in 1968, six manned landings between 1969 and 1972, with the first being Apollo 11. These missions returned lunar rocks which have been used to develop a geological understanding of the Moon's origin, internal structure, the Moon's history. Since the Apollo 17 mission in 1972, the Moon has been visited only by unmanned spacecraft.
Both the Moon's natural prominence in the earthly sky and its regular cycle of phases as seen from Earth have provided cultural references and influences for human societies and cultures since time immemorial. Such cultural influences can be found in language, lunar calendar systems and mythology; the usual English proper name for Earth's natural satellite is "the Moon", which in nonscientific texts is not capitalized. The noun moon is derived from Old English mōna, which stems from Proto-Germanic *mēnô, which comes from Proto-Indo-European *mḗh₁n̥s "moon", "month", which comes from the Proto-Indo-European root *meh₁- "to measure", the month being the ancient unit of time measured by the Moon; the name "Luna" is used. In literature science fiction, "Luna" is used to distinguish it from other moons, while in poetry, the name has been used to denote personification of Earth's moon; the modern English adjective pertaining to the Moon is lunar, derived from the Latin word for the Moon, luna. The adjective selenic is so used to refer to the Moon that this meaning is not recorded in most major dictionaries.
It is derived from the Ancient Greek word for the Moon, σελήνη, from, however derived the prefix "seleno-", as in selenography, the study of the physical features of the Moon, as well as the element name selenium. Both the Greek goddess Selene and the Roman goddess Diana were alternatively called Cynthia; the names Luna and Selene are reflected in terminology for lunar orbits in words such as apolune and selenocentric. The name Diana comes from the Proto-Indo-European *diw-yo, "heavenly", which comes from the PIE root *dyeu- "to shine," which in many derivatives means "sky and god" and is the origin of Latin dies, "day"; the Moon formed 4.51 billion years ago, some 60 million years after the origin of the Solar System. Several forming mechanisms have been proposed, including the fission of the Moon from Earth's crust through centrifugal force, the gravitational capture of a pre-formed Moon, the co-formation of Earth and the Moon together in the primordial accretion disk; these hypotheses cannot account for the high angular momentum of the Earth–Moon system.
The prevailing hypothesis is that the Earth–Moon system formed after an impact of a Mars-sized body with the proto-Earth. The impact blasted material into Earth's orbit and the material accreted and formed the Moon; the Moon's far side has a crust, 30 mi thicker than that of the near side. This is thought to be; this hypothesis, although not perfect best explains the evidence. Eighteen months prior to an October 1984 conference on lunar origins, Bill Hartmann, Roger Phillips, Jeff Taylor challenged fellow lunar scientists: "You have eighteen months. Go back to your Apollo data, go back to your computer, do whatever you have to, but make up your mind. Don't come to our conference unless you have something to say about the Moon's birth." At the 1984 conference at Kona, the giant impact hypothesis emerged as the most consensual theory. Before the conference, there were parti