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Origin. Occurrence. History. Production. Monetary use. Other applications. Toxicity. See also. References. Further reading. External links. Gold is a chemical element with the symbol Au (from the Latin word aurum) and the atomic number 79. In its pure form, it is a bright, slightly orange-yellow, dense, soft, malleable, and ductile metal.
Golden ratio. A golden rectangle with long side a + b and short side a can be divided into two pieces: a similar golden rectangle (shaded red, right) with long side a and short side b and a square (shaded blue, left) with sides of length a. This illustrates the relationship a + b a = a b = φ.
History is an academic discipline which uses a narrative to describe, examine, question, and analyze past events, and investigate their patterns of cause and effect. [6] [7] Historians debate which narrative best explains an event, as well as the significance of different causes and effects.
The geologic time scale or geological time scale ( GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochronology (a scientific branch of geology that aims to determine the age of rocks).
Ancient Greece ( Greek: Ἑλλάς, romanized : Hellás) was a northeastern Mediterranean civilization, existing from the Greek Dark Ages of the 12th–9th centuries BC to the end of classical antiquity ( c. 600 AD ), that comprised a loose collection of culturally and linguistically related city-states and other territories.
In the history of Europe, the Middle Ages or medieval period (also spelt mediaeval or mediæval) [1] [2] lasted from approximately 500 to 1500 AD, although some prefer other start and end dates. The Middle Ages is the second of the three traditional divisions of Western history: antiquity, medieval, and modern.
Genghis Khan (born Temüjin; c.1162 – August 1227), also known as Chinggis Khan, [a] was the founder and first khan of the Mongol Empire, which he ruled from 1206 until his death in 1227; it later became the largest contiguous empire in history.
