Diagram showing the relationship between the Zenith, the Nadir, and different types of Horizon. Note how the Nadir is opposite the Zenith.
The nadir (from Arabicﻧـدﻳﺭnadeerنظيرnathir, "opposite") is the astronomical term for the point in the sky directly below the observer, or more precisely, the point in the sky with an inclination of −90°. In simple terms, if you are standing on the earth, it is the direction "down" toward your feet. Look up nadir in Wiktionary, the free dictionary. ... Image File history File links Zenith-Nadir-Horizon. ... Image File history File links Zenith-Nadir-Horizon. ... In broad terms, the zenith is the direction pointing directly above a particular location (perpendicular, orthogonal). ... Horizon. ... Arabic redirects here. ... For other uses, see Astronomy (disambiguation). ...
Geometrically, it is the point on the celestial sphere intersected by a line drawn from the observer's location on the Earth's surface through the center of the Earth. The point opposite the nadir is the zenith. Nadir also refers to a downward-facing viewing angle of an orbiting satellite, such as is employed during remote sensing of the atmosphere. The celestial sphere is divided by the celestial equator. ... In broad terms, the zenith is the direction pointing directly above a particular location (perpendicular, orthogonal). ... For other uses, see Satellite (disambiguation). ... Air redirects here. ...
Nadir also means rare or unique in Arabic and Hebrew (נדיר).
Other sciences
By association, nadir is also used to mean the lowest point in a number of fields:
In hydrology nadir may refer to the low point in a lake level varying by season or for a long term natural cycle.
In economics, nadir means a low in the price of products.
In medicine, nadir can also be used to refer to the lowest blood count for a given patient in a given period of time (i.e., a patient's ANC Nadir or absolute neutrophil count). For example, patients undergoing chemotherapy will exhibit an ANC Nadir a week after starting therapy due to bone marrow suppression.
Nadir Shah (Persian: نادر شاه) (Nadir Qoli Beg (Persian: نادر قلی بیگ), also Tahmasp-Qoli Khan (Persian: تهماسپ قلی خان) also Nadir Shah Afshar (Persian: نادر شاه افشار)) (October 22, 1688 - June, 1747) ruled as Shah of Iran (1736–47) and was the founder of the short-lived Afsharid dynasty.
Nadir was given the cities on the west of Aras River in addition to Karbala and Basra in southern Iraq.
Nadir was surprised in his sleep by Salah Bey, captain of the guards, and cut with a sword.
Nadir, however, was the powerful figure of the realm.
In 1736 Nadir deposed Abbas and himself became shah, thus ending the rule of the Safavid dynasty.
Although the dynasty he founded, the Afshar dynasty (173649), was short-lived, Nadir is generally regarded as one of the greatest of all rulers of Persia.