a shadow cast by variation

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• Shadow — A shadow is an area where direct light from a light source cannot reach due to obstruction by an object. It occupies all of the space behind an opaque object with light in front of it. The cross section of a shadow is a two dimensional silhouette …   Wikipedia

• Shadow volume — Example of Carmack s stencil shadowing in Doom 3. Shadow volume is a technique used in 3D computer graphics to add shadows to a rendered scene. They were first proposed by Frank Crow in 1977[1] as the geometry describing the 3D shape of the… …   Wikipedia

• Backstaff — Not to be confused with Ballastella. Davis quadrant from the beginning of the 18th century The backstaff or back quadrant is a navigational instrument that was used to measure the altitude of a celestial body, in particular the sun or moon. When… …   Wikipedia

• Equation of time — The equation of time is the difference over the course of a year between time as read from a sundial and time as read from a clock, measured in an ideal situation (ie. in a location at the centre of a time zone, and which does not use daylight… …   Wikipedia

• shade — I (New American Roget s College Thesaurus) n. shadiness, shadow, umbrage, gloom, gloaming, dimness, darkness; obscurity; duskiness; shading, tone; curtain, veil, film, haziness, haze, misti[ness], cloudiness; color, hue, tint; nuance, degree;… …   English dictionary for students

• History of timekeeping devices — For thousands of years, devices have been used to measure and keep track of time. The current sexagesimal system of time measurement dates to approximately 2000 BC, in Sumer. The Ancient Egyptians divided the day into two 12 hour periods, and… …   Wikipedia

• physical science, principles of — Introduction       the procedures and concepts employed by those who study the inorganic world.        physical science, like all the natural sciences, is concerned with describing and relating to one another those experiences of the surrounding… …   Universalium

• Ethnic Malays — This article is about the Malay ethnic group. For the Malay race, see Malay race. For other uses, see Malay (disambiguation). Malay Melayu ملايو …   Wikipedia

• Hipparchus — (Greek polytonic|Ἵππαρχος; ca. 190 BC ndash; ca. 120 BC) was a Greek astronomer, geographer, and mathematician of the Hellenistic period.Hipparchus was born in Nicaea (now Iznik, Turkey), and probably died on the island of Rhodes. He is known to… …   Wikipedia

• CULTURAL LIFE — Introduction The movement for the return to Zion which emerged as a force at the end of the 19th century was based on a variety of motivations, including the political – the demand for an independent homeland where the Jews could forge their own… …   Encyclopedia of Judaism

• Eye — For other uses, see Eye (disambiguation), Ocular (disambiguation), Ocular, and Oculus. For taxon specific articles, see human eye, simple eye in invertebrates, mollusc eye, and arthropod eye. Eye …   Wikipedia