sphericity
21Dark Ages (historiography) — Petrarch, who conceived the idea of a European Dark Age . From Cycle of Famous Men and Women, Andrea di Bartolo di Bargilla, c. 1450 Dark Ages is a historical periodization emphasizing the cultural and economic deterioration that supposedly… …
22Zhang Heng — For other uses, see Zhang Heng (disambiguation). This is a Chinese name; the family name is Zhang. Zhang Heng (張衡) Born …
23Sedimentary rock — Middle Triassic marginal marine sequence of siltstones (below) and limestones (above), Virgin Formation, southwestern Utah, USA Sedimentary rock are types of rock that are formed by the deposition of material at the Earth s surface and within… …
24Mappa mundi — The Hereford Mappa Mundi, about 1300, Hereford Cathedral, England. Mappa mundi (Latin [ˈmappa ˈmʊndiː]; plural = mappae mundi) is a general term used to describe medieval European maps of the world. These maps range in size and complexity from… …
25Microsphere — Not to be confused with microparticle. Microsphere are small spherical particles, with diameters in the micrometer range (typically 1 μm to 1000 μm (1 mm)). Microspheres are sometimes referred to as microparticles. Microspheres can …
26Roundness (object) — Roundness is the measure of the sharpness of a particle s edges and corners. Calculation in two dimensions A single trace covering the full rotation is made and at each equally spaced angle, heta i, a measurement, R i, of the radius or distance… …
27Myth of the Flat Earth — For mythologies involving the belief in a Flat Earth, see Flat Earth. The famous Flat Earth Flammarion engraving originates with Flammarion s 1888 L atmosphère: météorologie populaire (p. 163) …
28map — mappable, adj. mapper, n. /map/, n., v., mapped, mapping. n. 1. a representation, usually on a flat surface, as of the features of an area of the earth or a portion of the heavens, showing them in their respective forms, sizes, and relationships… …
29Map — /map/, n. Walter, c1140 1209?, Welsh ecclesiastic, poet, and satirist. Also, Mapes /mayps, may peez/. * * * I Graphic representation, drawn to scale and usually on a flat surface, of features usually geographic, geologic, or geopolitical of an… …
30MAP — See modified American plan. * * * I Graphic representation, drawn to scale and usually on a flat surface, of features usually geographic, geologic, or geopolitical of an area of the Earth or of any celestial body. Globes are maps represented on… …
