half-spherical
71Fusion power — The Sun is a natural fusion reactor. Fusion power is the power generated by nuclear fusion processes. In fusion reactions two light atomic nuclei fuse together to form a heavier nucleus (in contrast with fission power). In doing so they release a …
72Dalek variants — …
73Muḥammad ibn Mūsā al-Khwārizmī — al Khwārizmī redirects here. For other uses, see al Khwārizmī (disambiguation). Muḥammad ibn Mūsā al Khwārizmī …
74Polyhedron — Polyhedra redirects here. For the relational database system, see Polyhedra DBMS. For the game magazine, see Polyhedron (magazine). For the scientific journal, see Polyhedron (journal). Some Polyhedra Dodecahedron (Regular polyhedron) …
75galaxy — /gal euhk see/, n., pl. galaxies. 1. Astron. a. a large system of stars held together by mutual gravitation and isolated from similar systems by vast regions of space. b. (usually cap.) See Milky Way. 2. any large and brilliant or impressive… …
76Alhazen — For the Moon crater, see Alhazen (crater). For the asteroid, see 59239 Alhazen. Alhazen Alhazen (Ibn al Haytham) …
77Hipparchus — (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… …
78X-ray crystallography — can locate every atom in a zeolite, an aluminosilicate with many important applications, such as water purification. X ray crystallography is a method of determining the arrangement of atoms within a crystal, in which a beam of X rays strikes a… …
79Hyperbolic geometry — Lines through a given point P and asymptotic to line R. A triangle immersed in a saddle shape plane (a hyperbolic paraboloid), as well as two diverging ultraparall …
80Schwarzschild coordinates — In the theory of Lorentzian manifolds, spherically symmetric spacetimes admit a family of nested round spheres . In such a spacetime, a particularly important kind of coordinate chart is the Schwarzschild chart, a kind of polar spherical… …
