2016 Likewise, trading and bartering subsistence foods, particularly between different regions, is an ancient practice in Alaska and around the circumpolar north. Tom Yulsman, Discover Magazine, This marks the first time the poles of Venus have been directly studied, owing to Venus Express’ circumpolar orbit, which also allowed a global view. 2022 The chances of favorable winds persistently occurring such that the circumpolar deep water no longer flows onto the shelf and melts the ice is small. 2023 Permafrost thaw threatens hundreds of Arctic villages and cities, and could put up to 70 percent of circumpolar infrastructure at high risk by mid-century, his team writes, costing billions to repair roads, bolster structures, and ensure that trains don’t derail on warped tracks. Alena Naiden, Anchorage Daily News, 18 Aug. ISBN 978-2-85036-458-7.Recent Examples on the Web The widespread environmental changes are only expected to continue to affect circumpolar communities, which adds urgency to collaboration between engineers, permafrost scientists and Arctic residents. "We, the navigators : the ancient art of landfinding in the Pacific". "Sun will align directly over Kaaba, Islam's holiest shrine, on Friday". "Determining the Sacred Direction of Islam". : CS1 maint: location missing publisher ( link) Breve diccionario etimológico de la lengua castellana (in Spanish) (3rd ed.). Cambridge English Pronouncing Dictionary (18th ed.). Roach, Peter Setter, Jane Esling, John (eds.). On the International Space Station, zenith and nadir are used instead of up and down, referring to directions within and around the station, relative to the earth. The NASA Orbital Debris Observatory and the Large Zenith Telescope are both zenith telescopes, since the use of liquid mirrors meant these telescopes could only point straight up. The astronomical meridian is also determined by the zenith, and is defined as a circle on the celestial sphere that passes through the zenith, nadir, and the celestial poles.Ī zenith telescope is a type of telescope designed to point straight up at or near the zenith, and used for precision measurement of star positions, to simplify telescope construction, or both. In astronomy, the altitude in the horizontal coordinate system and the zenith angle are complementary angles, with the horizon perpendicular to the zenith. Īt a given location during the course of a day, the Sun reaches not only its zenith but also its nadir, at the antipode of that location 12 hours from solar noon. In Islamic astronomy, the passing of the Sun over the zenith of Mecca becomes the basis of the qibla observation by shadows twice a year on 27/28 May and 15/16 July. The Sun reaches the observer's zenith when it is 90° above the horizon, and this only happens between the Tropic of Cancer and the Tropic of Capricorn. a star) and the local zenith - that is, the complement of the altitude angle (or elevation angle). In a scientific context, the zenith is the direction of reference for measuring the zenith angle (or zenith angular distance), the angle between a direction of interest (e.g. This sense of the word is often used to describe the position of the Sun ("The sun reached its zenith."), but to an astronomer, the Sun does not have its own zenith and is at the zenith only if it is directly overhead. The term zenith sometimes means the highest point, way, or level reached by a celestial body on its daily apparent path around a given point of observation.
This happens only at solar noon on certain days in the tropics, where the trees' latitude and the Sun's declination are equal. Relevance and use Angles and planes of a celestial sphere The shadows of trees are the shortest on Earth when the Sun is directly overhead (at the zenith). Through the Old French cenith, zenith first appeared in the 17th century. It was reduced to samt ("direction") and miswritten as senit/ cenit, the m being misread as ni. The word zenith derives from an inaccurate reading of the Arabic expression سمت الرأس ( samt al-ras), meaning "direction of the head" or "path above the head", by Medieval Latin scribes in the Middle Ages (during the 14th century), possibly through Old Spanish. The zenith is the "highest" point on the celestial sphere. "Above" means in the vertical direction ( plumb line) opposite to the gravity direction at that location ( nadir). The zenith ( UK: / ˈ z ɛ n ɪ θ/, US: / ˈ z iː n ɪ θ/) is an imaginary point directly "above" a particular location, on the celestial sphere.
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Look up zenith in Wiktionary, the free dictionary.
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