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December Solstice
The December solstice, also known as the southern solstice, is the solstice that occurs each December – typically on 21 December, but may vary by one day in either direction according to the Gregorian calendar. In the Northern Hemisphere, the December solstice is the winter solstice (the day with the shortest period of daylight), whilst in the Southern Hemisphere it is the summer solstice (the day with the longest period of daylight). The solstice also marks the changing of seasons in many countries. 21 December is the first day of winter (in the Northern Hemisphere) and the first day of summer (in the Southern Hemisphere). __TOC__ Solar year The December-solstice solar year is the solar year based on the December solstice. It is thus the length of time between adjacent December solstices. The length of the December-solstice year has been relatively stable between 6000 BC and AD 2000, in the range of 49 minutes 30 seconds to 50 minutes in excess of 365 days 5 hou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Year
A tropical year or solar year (or tropical period) is the time that the Sun takes to return to the same position in the sky of a celestial body of the Solar System such as the Earth, completing a full cycle of seasons; for example, the time from vernal equinox to vernal equinox, or from summer solstice to summer solstice. It is the type of year used by tropical solar calendars. The solar year is one type of astronomical year and particular orbital period. Another type is the sidereal year (or sidereal orbital period), which is the time it takes Earth to complete one full orbit around the Sun as measured with respect to the fixed stars, resulting in a duration of 20 minutes longer than the tropical year, because of the precession of the equinoxes. Since antiquity, astronomers have progressively refined the definition of the tropical year. The entry for "year, tropical" in the '' Astronomical Almanac Online Glossary'' states: An equivalent, more descriptive, definition is "Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calendars
A calendar is a system of organizing days. This is done by giving names to periods of time, typically days, weeks, months and years. A date is the designation of a single and specific day within such a system. A calendar is also a physical record (often paper) of such a system. A calendar can also mean a list of planned events, such as a court calendar or a partly or fully chronological list of documents, such as a calendar of wills. Periods in a calendar (such as years and months) are usually, though not necessarily, synchronized with the cycle of the sun or the moon. The most common type of pre-modern calendar was the lunisolar calendar, a lunar calendar that occasionally adds one intercalary month to remain synchronized with the solar year over the long term. Etymology The term ''calendar'' is taken from , the term for the first day of the month in the Roman calendar, related to the verb 'to call out', referring to the "calling" of the new moon when it was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Midsummer
Midsummer is a celebration of the season of summer usually held at a date around the summer solstice. It has pagan pre-Christian roots in Europe. The undivided Christian Church designated June 24 as the feast day of the early Christian martyr St John the Baptist, and the observance of St John's Day begins the evening before, known as Saint John's Eve. These are commemorated by many Christian denominations, such as the Roman Catholic Church, Lutheran Churches, and Anglican Communion, as well as by freemasonry. In Sweden, the Midsummer is such an important festivity that there have been proposals to make the Midsummer's Eve the National Day of Sweden, instead of June 6. In Finland, Estonia, Latvia and Lithuania, Midsummer's festival is a public holiday. In Denmark and Norway, it may also be referred to as St. Hans Day. History Saint John's Day, the feast day of Saint John the Baptist, was established by the undivided Christian Church in the 4th century AD, in honour of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
September Equinox
The September equinox (or southward equinox) is the moment when the Sun appears to cross the celestial equator, heading southward. Because of differences between the calendar year and the tropical year, the September equinox may occur anytime from September 21 to 24. At the equinox, the Sun as viewed from the equator rises due east and sets due west. Before the Southward equinox, the Sun rises and sets more northerly, and afterwards, it rises and sets more southerly. The equinox may be taken to mark the end of astronomical summer and the beginning of astronomical autumn (autumnal equinox) in the Northern Hemisphere, while marking the end of astronomical winter and the start of astronomical spring (vernal equinox) in the Southern Hemisphere. Occurrences The September equinox is one point in time commonly used to determine the length of the tropical year. The dates and times of the September equinoxes that occur from the year 2017 to 2027 (UTC) are listed as follows: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
June Solstice
The June solstice is the solstice on Earth that occurs annually between 20 and 22 June according to the Gregorian calendar. In the Northern Hemisphere, the June solstice is the summer solstice (the day with the longest period of daylight), while in the Southern Hemisphere it is the winter solstice (the day with the shortest period of daylight). It is also known as the northern solstice. Solar year The June solstice solar year is the solar year based on the June solstice. It is thus the length of time between adjacent June solstices. The length of the day on June solstice See also Astronomy * March equinox * September equinox * December solstice Holidays * Holi Holi (), also known as the Festival of Colours, the Festival of Spring, and the Festival of Love,The New Oxford Dictionary of English (1998) p. 874 "Holi /'həʊli:/ noun a Hindu spring festival ...". is an ancient Hindu religious festival ... * Inti Raymi * Kupala Night * Midnight sun * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
March Equinox
The March equinox or northward equinox is the equinox on the Earth when the subsolar point appears to leave the Southern Hemisphere and cross the celestial equator, heading northward as seen from Earth. The March equinox is known as the vernal equinox (spring equinox) in the Northern Hemisphere and as the autumnal equinox in the Southern Hemisphere. On the Gregorian calendar, the northward equinox can occur as early as 19 March or as late as 21 March at 0° longitude. For a common year the computed time slippage is about 5 hours 49 minutes ''later'' than the previous year, and for a leap year about 18 hours 11 minutes ''earlier'' than the previous year. Balancing the increases of the common years against the losses of the leap years keeps the calendar date of the March equinox from drifting more than one day from 20 March each year. The March equinox may be taken to mark the beginning of astronomical spring and the end of astronomical winter in the Northern Hemisphere ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Summer
Summer is the hottest of the four temperate seasons, occurring after spring and before autumn. At or centred on the summer solstice, the earliest sunrise and latest sunset occurs, daylight hours are longest and dark hours are shortest, with day length decreasing as the season progresses after the solstice. The date of the beginning of summer varies according to climate, tradition, and culture. When it is summer in the Northern Hemisphere, it is winter in the Southern Hemisphere, and vice versa. Timing From an astronomical view, the equinoxes and solstices would be the middle of the respective seasons, but sometimes astronomical summer is defined as starting at the solstice, the time of maximal insolation, often identified with the 21st day of June or December. By solar reckoning, summer instead starts on May Day and the summer solstice is Midsummer. A variable seasonal lag means that the meteorological centre of the season, which is based on average temperature patte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solstice
A solstice is an event that occurs when the Sun appears to reach its most northerly or southerly excursion relative to the celestial equator on the celestial sphere. Two solstices occur annually, around June 21 and December 21. In many countries, the seasons of the year are determined by the solstices and the equinoxes. The term ''solstice'' can also be used in a broader sense, as the day when this occurs. The day of a solstice in either hemisphere has either the most sunlight of the year ( summer solstice) or the least sunlight of the year ( winter solstice) for any place other than the Equator. Alternative terms, with no ambiguity as to which hemisphere is the context, are "June solstice" and " December solstice", referring to the months in which they take place every year. The word ''solstice'' is derived from the Latin ''sol'' ("sun") and ''sistere'' ("to stand still"), because at the solstices, the Sun's declination appears to "stand still"; that is, the seasonal m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Winter
Winter is the coldest season of the year in polar and temperate climates. It occurs after autumn and before spring. The tilt of Earth's axis causes seasons; winter occurs when a hemisphere is oriented away from the Sun. Different cultures define different dates as the start of winter, and some use a definition based on weather. When it is winter in the Northern Hemisphere, it is summer in the Southern Hemisphere, and vice versa. In many regions, winter brings snow and freezing temperatures. The moment of winter solstice is when the Sun's elevation with respect to the North or South Pole is at its most negative value; that is, the Sun is at its farthest below the horizon as measured from the pole. The day on which this occurs has the shortest day and the longest night, with day length increasing and night length decreasing as the season progresses after the solstice. The earliest sunset and latest sunrise dates outside the polar regions differ from the date of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Summer Solstice
The summer solstice, also called the estival solstice or midsummer, occurs when one of Earth's poles has its maximum tilt toward the Sun. It happens twice yearly, once in each hemisphere (Northern and Southern). For that hemisphere, the summer solstice is the day with the longest period of daylight and shortest night of the year, when the Sun is at its highest position in the sky. Within the Arctic circle (for the Northern hemisphere) or Antarctic circle (for the Southern), there is continuous daylight around the summer solstice. The opposite event is the winter solstice. The summer solstice occurs during summer. This is the June solstice (usually 20 or 21 June) in the Northern hemisphere and the December solstice (usually 21 or 22 December) in the Southern. On the summer solstice, Earth's maximum axial tilt toward the Sun is 23.44°. Likewise, the Sun's declination from the celestial equator is 23.44°. Since prehistory, the summer solstice has been seen as a significant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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