153 relations: Absolute space and time, Albert Einstein, Amundsen–Scott South Pole Station, Analemma, Angular diameter, Antarctic Circle, Archaeological site, Arctic Circle, Aries (constellation), Astrolabe, Astronomical year numbering, Atacama people, Atmospheric refraction, Axial precession, Axial tilt, Aymara people, Bolivia, Cahokia, Cahokia Woodhenge, Canada, Cancer (astrology), Cancer (constellation), Capricorn (astrology), Capricornus, Celestial coordinate system, Celestial equator, Celestial navigation, Celestial sphere, Central Europe, Christian Church, Circle, Circumference, Cleomedes, Collinsville, Illinois, Colure, Constellation, Dakshinayana, December solstice, Declination, Earth, Earth's rotation, Easter, Eclipse, Ecliptic, El Fuerte de Samaipata, Ellipse, England, Equator, Equinox, Focus (geometry), ..., Frame of reference, Fremont Solstice Parade, Fremont, Seattle, Gate of the Sun, Gemini (constellation), Gnomon, Hanukkah, Hebrew calendar, Hindu calendar, Horizon, Horizontal coordinate system, Houghton Mifflin Harcourt, Indian Country Today, Inertial frame of reference, International Astronomical Union, Iran, Iranian calendars, Isaac Newton, Islamic calendar, Japan, John the Baptist, Judaism, June solstice, Korochun, Kupala Night, Kwanzaa, Latin, Leo (constellation), Makar Sankranti, Mapuche, Mars, Midnight sun, Midsummer, Minute and second of arc, Mississippian culture, Modern Paganism, Moon, Native Americans in the United States, Natural History (Pliny), New Zealand, North Pole, Northern Europe, Northern Hemisphere, Nowruz, Ophiuchus, Orbit, Orbital plane (astronomy), Parallel (geometry), Passover, Perihelion and aphelion, Perpendicular, Pinyin, Planet, Pliny the Elder, Polar night, Position of the Sun, Precession, Principle of relativity, Relative velocity, Right ascension, Roman Republic, Romanization of Japanese, Rotation, Sagittarius (constellation), Saint John's Eve, Sankranti, Saturnalia, Scorpius, Sea ice, Season, Setsubun, Sextant, Solar term, South America, South Pole, Southern Hemisphere, Sphere, Star, Subsolar point, Sukkot, Summer solstice, Sun, Sun path, Sunlight, Taurus (constellation), The American Heritage Dictionary of the English Language, Timber circle, Time zone, Tiwanaku, Tropic of Cancer, Tropic of Capricorn, United States, United States Naval Observatory, University of California Press, Uttarayana, Vernier scale, We Tripantu, Wheel of the Year, Winter solstice, Yaldā Night, Yule, Zodiac, Zoroastrian calendar. Expand index (103 more) » « Shrink index
Absolute space and time is a concept in physics and philosophy about the properties of the universe.
Albert Einstein (14 March 1879 – 18 April 1955) was a German-born theoretical physicist who developed the theory of relativity, one of the two pillars of modern physics (alongside quantum mechanics).
The Amundsen–Scott South Pole Station is a United States scientific research station at the South Pole, the southernmost place on the Earth.
In astronomy, an analemma (from Greek ἀνάλημμα analēmma "support") is a diagram showing the variation of the position of the Sun in the sky over the course of a year, as viewed at a fixed time of day and from a fixed location on the Earth.
The angular diameter, angular size, apparent diameter, or apparent size is an angular measurement describing how large a sphere or circle appears from a given point of view.
The Antarctic Circle is the most southerly of the five major circles of latitude that mark maps of the Earth.
An archaeological site is a place (or group of physical sites) in which evidence of past activity is preserved (either prehistoric or historic or contemporary), and which has been, or may be, investigated using the discipline of archaeology and represents a part of the archaeological record.
The Arctic Circle is the most northerly of the five major circles of latitude as shown on maps of Earth.
Aries is one of the constellations of the zodiac.
An astrolabe (ἀστρολάβος astrolabos; ٱلأَسْطُرلاب al-Asturlāb; اَختِرِیاب Akhteriab) is an elaborate inclinometer, historically used by astronomers and navigators to measure the inclined position in the sky of a celestial body, day or night.
Astronomical year numbering is based on AD/CE year numbering, but follows normal decimal integer numbering more strictly.
The Atacama people, known as atacameños or atacamas in Spanish and kunzas, likan-antai or likanantaí in English, are an indigenous people from the Atacama Desert and altiplano region in the north of Chile and Argentina and southern Bolivia.
Atmospheric refraction is the deviation of light or other electromagnetic wave from a straight line as it passes through the atmosphere due to the variation in air density as a function of height.
In astronomy, axial precession is a gravity-induced, slow, and continuous change in the orientation of an astronomical body's rotational axis.
In astronomy, axial tilt, also known as obliquity, is the angle between an object's rotational axis and its orbital axis, or, equivalently, the angle between its equatorial plane and orbital plane.
The Aymara or Aimara (aymara) people are an indigenous nation in the Andes and Altiplano regions of South America; about 1 million live in Bolivia, Peru and Chile.
Bolivia (Mborivia; Buliwya; Wuliwya), officially known as the Plurinational State of Bolivia (Estado Plurinacional de Bolivia), is a landlocked country located in western-central South America.
The Cahokia Mounds State Historic Site (11 MS 2) is the site of a pre-Columbian Native American city (circa 1050–1350 CE) directly across the Mississippi River from modern St. Louis, Missouri.
The Cahokia Woodhenge was a series of large timber circles located roughly to the west of Monks Mound at the Mississippian culture Cahokia archaeological site near Collinsville, Illinois.
Canada is a country located in the northern part of North America.
Cancer (♋️) is the fourth astrological sign in the Zodiac, originating from the constellation of Cancer.
Cancer is one of the twelve constellations of the zodiac.
Capricorn ♑- is the tenth astrological sign in the zodiac, originating from the constellation of Capricornus.
Capricornus is one of the constellations of the zodiac.
In astronomy, a celestial coordinate system is a system for specifying positions of celestial objects: satellites, planets, stars, galaxies, and so on.
The celestial equator is the great circle of the imaginary celestial sphere on the same plane as the equator of Earth.
Celestial navigation, also known as astronavigation, is the ancient and modern practice of position fixing that enables a navigator to transition through a space without having to rely on estimated calculations, or dead reckoning, to know their position.
In astronomy and navigation, the celestial sphere is an abstract sphere with an arbitrarily large radius concentric to Earth.
Central Europe is the region comprising the central part of Europe.
"Christian Church" is an ecclesiological term generally used by Protestants to refer to the whole group of people belonging to Christianity throughout the history of Christianity.
A circle is a simple closed shape.
In geometry, the circumference (from Latin circumferentia, meaning "carrying around") of a circle is the (linear) distance around it.
Cleomedes (Κλεομήδης) was a Greek astronomer who is known chiefly for his book On the Circular Motions of the Celestial Bodies (Κυκλικὴ θεωρία μετεώρων).
Collinsville is a city located mainly in Madison County, and partially in St. Clair County, both in Illinois.
Colure, in astronomy, is either of the two principal meridians of the celestial sphere.
A constellation is a group of stars that are considered to form imaginary outlines or meaningful patterns on the celestial sphere, typically representing animals, mythological people or gods, mythological creatures, or manufactured devices.
Dakshinayana (दक्षिणायण) is the six-month period between Summer solstice and Winter solstice, when the sun travels towards the south on the celestial sphere.
The December solstice, also known as the southern solstice, is the solstice that occurs each December, typically between the 20th and the 22nd day of the month according to the Gregorian calendar.
In astronomy, declination (abbreviated dec; symbol δ) is one of the two angles that locate a point on the celestial sphere in the equatorial coordinate system, the other being hour angle.
Earth is the third planet from the Sun and the only astronomical object known to harbor life.
Earth's rotation is the rotation of Planet Earth around its own axis.
Easter,Traditional names for the feast in English are "Easter Day", as in the Book of Common Prayer, "Easter Sunday", used by James Ussher and Samuel Pepys and plain "Easter", as in books printed in,, also called Pascha (Greek, Latin) or Resurrection Sunday, is a festival and holiday celebrating the resurrection of Jesus from the dead, described in the New Testament as having occurred on the third day of his burial after his crucifixion by the Romans at Calvary 30 AD.
An eclipse is an astronomical event that occurs when an astronomical object is temporarily obscured, either by passing into the shadow of another body or by having another body pass between it and the viewer.
The ecliptic is the circular path on the celestial sphere that the Sun follows over the course of a year; it is the basis of the ecliptic coordinate system.
El Fuerte de Samaipata or Fort Samaipata, also known simply as "El Fuerte", is a Pre-Columbian archaeological site and UNESCO World Heritage Site located in Florida Province, Santa Cruz Department, Bolivia.
In mathematics, an ellipse is a curve in a plane surrounding two focal points such that the sum of the distances to the two focal points is constant for every point on the curve.
England is a country that is part of the United Kingdom.
An equator of a rotating spheroid (such as a planet) is its zeroth circle of latitude (parallel).
An equinox is commonly regarded as the moment the plane (extended indefinitely in all directions) of Earth's equator passes through the center of the Sun, which occurs twice each year, around 20 March and 22-23 September.
In geometry, focuses or foci, singular focus, are special points with reference to which any of a variety of curves is constructed.
In physics, a frame of reference (or reference frame) consists of an abstract coordinate system and the set of physical reference points that uniquely fix (locate and orient) the coordinate system and standardize measurements.
The Fremont Solstice Parade is an annual event produced in June by the Fremont Arts Council (FAC), a non-profit organization based in the Fremont neighborhood of Seattle, Washington, USA, that supports the arts and artists in and around the city.
Fremont is a neighborhood in Seattle, Washington.
The Gate of the Sun is a megalithic solid stone arch or gateway constructed by the ancient Tiwanaku culture of Bolivia.
Gemini is one of the constellations of the zodiac.
A gnomon (from Greek γνώμων, gnōmōn, literally: "one that knows or examines") is the part of a sundial that casts a shadow.
Hanukkah (חֲנֻכָּה, Tiberian:, usually spelled rtl, pronounced in Modern Hebrew, or in Yiddish; a transliteration also romanized as Chanukah or Ḥanukah) is a Jewish holiday commemorating the rededication of the Holy Temple (the Second Temple) in Jerusalem at the time of the Maccabean Revolt against the Seleucid Empire.
The Hebrew or Jewish calendar (Ha-Luah ha-Ivri) is a lunisolar calendar used today predominantly for Jewish religious observances.
Hindu calendar is a collective term for the various lunisolar calendars traditionally used in India.
The horizon or skyline is the apparent line that separates earth from sky, the line that divides all visible directions into two categories: those that intersect the Earth's surface, and those that do not.
The horizontal coordinate system is a celestial coordinate system that uses the observer's local horizon as the fundamental plane.
Houghton Mifflin Harcourt (HMH) is an educational and trade publisher in the United States.
Indian Country Today (ICT, formerly known as ICMN, or ICTMN) is a website and formerly weekly online newsletter that is a national news source for and about Native American people in North America as well as First Nations people in Canada and Indigenous people worldwide.
An inertial frame of reference in classical physics and special relativity is a frame of reference in which a body with zero net force acting upon it is not accelerating; that is, such a body is at rest or it is moving at a constant speed in a straight line.
The International Astronomical Union (IAU; Union astronomique internationale, UAI) is an international association of professional astronomers, at the PhD level and beyond, active in professional research and education in astronomy.
Iran (ایران), also known as Persia, officially the Islamic Republic of Iran (جمهوری اسلامی ایران), is a sovereign state in Western Asia. With over 81 million inhabitants, Iran is the world's 18th-most-populous country. Comprising a land area of, it is the second-largest country in the Middle East and the 17th-largest in the world. Iran is bordered to the northwest by Armenia and the Republic of Azerbaijan, to the north by the Caspian Sea, to the northeast by Turkmenistan, to the east by Afghanistan and Pakistan, to the south by the Persian Gulf and the Gulf of Oman, and to the west by Turkey and Iraq. The country's central location in Eurasia and Western Asia, and its proximity to the Strait of Hormuz, give it geostrategic importance. Tehran is the country's capital and largest city, as well as its leading economic and cultural center. Iran is home to one of the world's oldest civilizations, beginning with the formation of the Elamite kingdoms in the fourth millennium BCE. It was first unified by the Iranian Medes in the seventh century BCE, reaching its greatest territorial size in the sixth century BCE, when Cyrus the Great founded the Achaemenid Empire, which stretched from Eastern Europe to the Indus Valley, becoming one of the largest empires in history. The Iranian realm fell to Alexander the Great in the fourth century BCE and was divided into several Hellenistic states. An Iranian rebellion culminated in the establishment of the Parthian Empire, which was succeeded in the third century CE by the Sasanian Empire, a leading world power for the next four centuries. Arab Muslims conquered the empire in the seventh century CE, displacing the indigenous faiths of Zoroastrianism and Manichaeism with Islam. Iran made major contributions to the Islamic Golden Age that followed, producing many influential figures in art and science. After two centuries, a period of various native Muslim dynasties began, which were later conquered by the Turks and the Mongols. The rise of the Safavids in the 15th century led to the reestablishment of a unified Iranian state and national identity, with the country's conversion to Shia Islam marking a turning point in Iranian and Muslim history. Under Nader Shah, Iran was one of the most powerful states in the 18th century, though by the 19th century, a series of conflicts with the Russian Empire led to significant territorial losses. Popular unrest led to the establishment of a constitutional monarchy and the country's first legislature. A 1953 coup instigated by the United Kingdom and the United States resulted in greater autocracy and growing anti-Western resentment. Subsequent unrest against foreign influence and political repression led to the 1979 Revolution and the establishment of an Islamic republic, a political system that includes elements of a parliamentary democracy vetted and supervised by a theocracy governed by an autocratic "Supreme Leader". During the 1980s, the country was engaged in a war with Iraq, which lasted for almost nine years and resulted in a high number of casualties and economic losses for both sides. According to international reports, Iran's human rights record is exceptionally poor. The regime in Iran is undemocratic, and has frequently persecuted and arrested critics of the government and its Supreme Leader. Women's rights in Iran are described as seriously inadequate, and children's rights have been severely violated, with more child offenders being executed in Iran than in any other country in the world. Since the 2000s, Iran's controversial nuclear program has raised concerns, which is part of the basis of the international sanctions against the country. The Joint Comprehensive Plan of Action, an agreement reached between Iran and the P5+1, was created on 14 July 2015, aimed to loosen the nuclear sanctions in exchange for Iran's restriction in producing enriched uranium. Iran is a founding member of the UN, ECO, NAM, OIC, and OPEC. It is a major regional and middle power, and its large reserves of fossil fuels – which include the world's largest natural gas supply and the fourth-largest proven oil reserves – exert considerable influence in international energy security and the world economy. The country's rich cultural legacy is reflected in part by its 22 UNESCO World Heritage Sites, the third-largest number in Asia and eleventh-largest in the world. Iran is a multicultural country comprising numerous ethnic and linguistic groups, the largest being Persians (61%), Azeris (16%), Kurds (10%), and Lurs (6%).
The Iranian calendars (گاهشماری ایرانی Gâhshomâriye Irâni) are a succession of calendars invented or used for over two millennia in Iran (Persia).
Sir Isaac Newton (25 December 1642 – 20 March 1726/27) was an English mathematician, astronomer, theologian, author and physicist (described in his own day as a "natural philosopher") who is widely recognised as one of the most influential scientists of all time, and a key figure in the scientific revolution.
The Islamic, Muslim, or Hijri calendar (التقويم الهجري at-taqwīm al-hijrī) is a lunar calendar consisting of 12 months in a year of 354 or 355 days.
Japan (日本; Nippon or Nihon; formally 日本国 or Nihon-koku, lit. "State of Japan") is a sovereign island country in East Asia.
John the Baptist (יוחנן המטביל Yokhanan HaMatbil, Ἰωάννης ὁ βαπτιστής, Iōánnēs ho baptistḗs or Ἰωάννης ὁ βαπτίζων, Iōánnēs ho baptízōn,Lang, Bernhard (2009) International Review of Biblical Studies Brill Academic Pub p. 380 – "33/34 CE Herod Antipas's marriage to Herodias (and beginning of the ministry of Jesus in a sabbatical year); 35 CE – death of John the Baptist" ⲓⲱⲁⲛⲛⲏⲥ ⲡⲓⲡⲣⲟⲇⲣⲟⲙⲟⲥ or ⲓⲱ̅ⲁ ⲡⲓⲣϥϯⲱⲙⲥ, يوحنا المعمدان) was a Jewish itinerant preacherCross, F. L. (ed.) (2005) Oxford Dictionary of the Christian Church, 3rd ed.
Judaism (originally from Hebrew, Yehudah, "Judah"; via Latin and Greek) is the religion of the Jewish people.
The June solstice, also known as the northern solstice, is the solstice on the Earth that occurs each June falling on the 20th to 22nd according to the Gregorian calendar.
Koročun or Kračun (see other variants below) one of the names of Slavic pagan holiday Koliada.
Kupala Night, (Іван Купала; Купалле; Иван-Купала; Noc Kupały), is celebrated in Ukraine, Poland, Belarus and Russia, currently on the night of 6/7 July in the Gregorian calendar, which is 24/25 June in the Julian calendar.
Kwanzaa is a celebration held in the United States and in other nations of the African diaspora in the Americas and lasts a week.
Latin (Latin: lingua latīna) is a classical language belonging to the Italic branch of the Indo-European languages.
Leo is one of the constellations of the zodiac, lying between Cancer the crab to the west and Virgo the maiden to the east.
Makar Sankranti, also known as Makara Sankrānti (Sanskrit: मकर सङ्क्रान्ति) or Maghi, is a festival day in the Hindu calendar, in reference to deity Surya (sun).
The Mapuche are a group of indigenous inhabitants of south-central Chile and southwestern Argentina, including parts of present-day Patagonia.
Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System after Mercury.
The midnight sun is a natural phenomenon that occurs in the summer months in places north of the Arctic Circle or south of the Antarctic Circle, when the sun remains visible at the local midnight.
Midsummer is the period of time centered upon the summer solstice, and more specifically the northern European celebrations that accompany the actual solstice or take place on a day between June 19 and June 25 and the preceding evening.
A minute of arc, arcminute (arcmin), arc minute, or minute arc is a unit of angular measurement equal to of one degree.
The Mississippian culture was a mound-building Native American civilization archeologists date from approximately 800 CE to 1600 CE, varying regionally.
Modern Paganism, also known as Contemporary Paganism and Neopaganism, is a collective term for new religious movements influenced by or claiming to be derived from the various historical pagan beliefs of pre-modern Europe, North Africa and the Near East.
The Moon is an astronomical body that orbits planet Earth and is Earth's only permanent natural satellite.
Native Americans, also known as American Indians, Indians, Indigenous Americans and other terms, are the indigenous peoples of the United States.
The Natural History (Naturalis Historia) is a book about the whole of the natural world in Latin by Pliny the Elder, a Roman author and naval commander who died in 79 AD.
New Zealand (Aotearoa) is a sovereign island country in the southwestern Pacific Ocean.
The North Pole, also known as the Geographic North Pole or Terrestrial North Pole, is (subject to the caveats explained below) defined as the point in the Northern Hemisphere where the Earth's axis of rotation meets its surface.
Northern Europe is the general term for the geographical region in Europe that is approximately north of the southern coast of the Baltic Sea.
The Northern Hemisphere is the half of Earth that is north of the Equator.
Nowruz (نوروز,; literally "new day") is the name of the Iranian New Year, also known as the Persian New Year, which is celebrated worldwide by various ethno-linguistic groups as the beginning of the New Year.
Ophiuchus is a large constellation straddling the celestial equator.
In physics, an orbit is the gravitationally curved trajectory of an object, such as the trajectory of a planet around a star or a natural satellite around a planet.
The orbital plane of a revolving body is the geometric plane on which its orbit lies.
In geometry, parallel lines are lines in a plane which do not meet; that is, two lines in a plane that do not intersect or touch each other at any point are said to be parallel.
Passover or Pesach (from Hebrew Pesah, Pesakh) is a major, biblically derived Jewish holiday.
The perihelion of any orbit of a celestial body about the Sun is the point where the body comes nearest to the Sun.
In elementary geometry, the property of being perpendicular (perpendicularity) is the relationship between two lines which meet at a right angle (90 degrees).
Hanyu Pinyin Romanization, often abbreviated to pinyin, is the official romanization system for Standard Chinese in mainland China and to some extent in Taiwan.
A planet is an astronomical body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.
Pliny the Elder (born Gaius Plinius Secundus, AD 23–79) was a Roman author, naturalist and natural philosopher, a naval and army commander of the early Roman Empire, and friend of emperor Vespasian.
The polar night occurs in the northernmost and southernmost regions of the Earth when the night lasts for more than 24 hours.
The position of the Sun in the sky is a function of both the time and the geographic location of observation on Earth's surface.
Precession is a change in the orientation of the rotational axis of a rotating body.
In physics, the principle of relativity is the requirement that the equations describing the laws of physics have the same form in all admissible frames of reference.
The relative velocity \vec_ (also \vec_ or \vec_) is the velocity of an object or observer B in the rest frame of another object or observer A.
Right ascension (abbreviated RA; symbol) is the angular distance measured only eastward along the celestial equator from the Sun at the March equinox to the (hour circle of the) point above the earth in question.
The Roman Republic (Res publica Romana) was the era of classical Roman civilization beginning with the overthrow of the Roman Kingdom, traditionally dated to 509 BC, and ending in 27 BC with the establishment of the Roman Empire.
The romanization of Japanese is the use of Latin script to write the Japanese language.
A rotation is a circular movement of an object around a center (or point) of rotation.
Sagittarius is one of the constellations of the zodiac.
When the sun sets on 23 June, Saint John's Eve, is the eve of celebration before the Feast Day of Saint John the Baptist.
Sankranti (संक्रान्ति saṁkrānti) means transmigration of the Sun from one Rāshi (constellation of the zodiac in Indian astronomy) to the next.
Saturnalia was an ancient Roman festival in honour of the god Saturn, held on 17 December of the Julian calendar and later expanded with festivities through to 23 December.
Scorpius is one of the constellations of the zodiac.
Sea ice arises as seawater freezes.
A season is a division of the year marked by changes in weather, ecology, and amount of daylight.
is the day before the beginning of spring in Japan.
A sextant is a doubly reflecting navigation instrument that measures the angular distance between two visible objects.
A solar term is any of 24 points in traditional East Asian lunisolar calendars that matches a particular astronomical event or signifies some natural phenomenon.
South America is a continent in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere.
The South Pole, also known as the Geographic South Pole or Terrestrial South Pole, is one of the two points where the Earth's axis of rotation intersects its surface.
The Southern Hemisphere is the half of Earth that is south of the Equator.
A sphere (from Greek σφαῖρα — sphaira, "globe, ball") is a perfectly round geometrical object in three-dimensional space that is the surface of a completely round ball (viz., analogous to the circular objects in two dimensions, where a "circle" circumscribes its "disk").
A star is type of astronomical object consisting of a luminous spheroid of plasma held together by its own gravity.
The subsolar point on a planet is where its sun is perceived to be directly overhead (in zenith); that is where the sun's rays are hitting the planet exactly perpendicular to its surface.
Sukkot (סוכות or סֻכּוֹת,, commonly translated as Feast of Tabernacles or Feast of the Ingathering, traditional Ashkenazi pronunciation Sukkos or Succos, literally Feast of Booths) is a biblical Jewish holiday celebrated on the 15th day of the seventh month, Tishrei (varies from late September to late October).
The summer solstice (or estival solstice), also known as midsummer, occurs when one of the Earth's poles has its maximum tilt toward the Sun.
The Sun is the star at the center of the Solar System.
Sun path, sometimes also called day arc, refers to the daily and seasonal arc-like path that the Sun appears to follow across the sky as the Earth rotates and orbits the Sun.
Sunlight is a portion of the electromagnetic radiation given off by the Sun, in particular infrared, visible, and ultraviolet light.
Taurus (Latin for "the Bull") is one of the constellations of the zodiac, which means it is crossed by the plane of the ecliptic.
The American Heritage Dictionary of the English Language (AHD) is an American dictionary of English published by Boston publisher Houghton Mifflin, the first edition of which appeared in 1969.
In archaeology, timber circles are circular arrangements of wooden posts interpreted as being either complexes of freestanding totem poles or as the supports for large circular buildings.
A time zone is a region of the globe that observes a uniform standard time for legal, commercial, and social purposes.
Tiwanaku (Tiahuanaco or Tiahuanacu) is a Pre-Columbian archaeological site in western Bolivia.
The Tropic of Cancer, also referred to as the Northern Tropic, is the most northerly circle of latitude on Earth at which the Sun can be directly overhead.
The Tropic of Capricorn (or the Southern Tropic) is the circle of latitude that contains the subsolar point on the December (or southern) solstice.
The United States of America (USA), commonly known as the United States (U.S.) or America, is a federal republic composed of 50 states, a federal district, five major self-governing territories, and various possessions.
The United States Naval Observatory (USNO) is one of the oldest scientific agencies in the United States, with a primary mission to produce Positioning, Navigation and Timing (PNT) for the United States Navy and the United States Department of Defense.
University of California Press, otherwise known as UC Press, is a publishing house associated with the University of California that engages in academic publishing.
The Surya Siddhanta defines Uttarāyaṇa or Uttarayan as the period between the Makara Sankranti (which currently occurs around January 14) and Karka Sankranti (which currently occurs around July 16).
A vernier scale is a visual aid that allows the user to measure more precisely than could be done unaided when reading a uniformly divided straight or circular measurement scale.
Wiñoy Tripantu is the Mapuche celebration of the return of the sun and is sometimes called the Mapuche New Year (Beca de investigación). Informe final 2003.
The Wheel of the Year is an annual cycle of seasonal festivals, observed by many modern Pagans.
The winter solstice (or hibernal solstice), also known as midwinter, is an astronomical phenomenon marking the day with the shortest period of daylight and the longest night of the year.
Shab-e Yalda ("Yalda night" شب یلدا) or Shab-e Chelleh ("night of forty", شب چله) is an Iranian festival celebrated on the "longest and darkest night of the year," Yalda is a winter solstice celebration, that is, in the night of the Northern Hemisphere's winter solstice.
Yule or Yuletide ("Yule time") was and is a festival observed by the historical Germanic peoples.
The zodiac is an area of the sky that extends approximately 8° north or south (as measured in celestial latitude) of the ecliptic, the apparent path of the Sun across the celestial sphere over the course of the year.
Adherents of Zoroastrianism use three distinct versions of traditional calendars for liturgical purposes, all derived from medieval Iranian calendars, ultimately based on the Babylonian calendar as used in the Achaemenid empire.
Ecliptic peak, First Point of Cancer, First Point of Capricorn, First point of Cancer, First point of Capricorn, First point of cancer, First point of capricorn, Solstices, Solstitial point, Summer equinox, Winter equinox.