Search results
Results From The WOW.Com Content Network
The four spheres (for which most of the other spheres are a subtype of) are the atmosphere, the biosphere, the hydrosphere and the geosphere. Earth's ecosphere lies it self within the heliosphere (the Sun's astrosphere). [4] Listed roughly from outermost to innermost the named spheres of the Earth are:
In Greek antiquity the ideas of celestial spheres and rings first appeared in the cosmology of Anaximander in the early 6th century BC. [7] In his cosmology both the Sun and Moon are circular open vents in tubular rings of fire enclosed in tubes of condensed air; these rings constitute the rims of rotating chariot-like wheels pivoting on the Earth at their centre.
[4] In this way, astronomers can predict geocentric or heliocentric positions of objects on the celestial sphere, without the need to calculate the individual geometry of any particular observer, and the utility of the celestial sphere is maintained. Individual observers can work out their own small offsets from the mean positions, if necessary.
Since spherical geometry violates the parallel postulate, there exists no such triangle on the surface of a sphere. The sum of the angles of a triangle on a sphere is 180°(1 + 4f), where f is the fraction of the sphere's surface that is enclosed by the triangle.
[4] [5] The Goldberg–Coxeter construction is an expansion of the concepts underlying geodesic polyhedra. 3 constructions for a {3,5+} 6,0 An icosahedron and related symmetry polyhedra can be used to define a high geodesic polyhedron by dividing triangular faces into smaller triangles, and projecting all the new vertices onto a sphere.
In this sense, the biosphere is but one of four separate components of the geochemical model, the other three being geosphere, hydrosphere, and atmosphere. When these four component spheres are combined into one system, it is known as the ecosphere. This term was coined during the 1960s and encompasses both biological and physical components of ...
The Middle Ages broadly inherited the concept of the four elements of earth, water, air and fire arranged in concentric spheres about the earth as centre: [3] as the purest of the four elements, fire - and the sphere of fire - stood highest in the ascending sequence of the scala naturae, and closest to the superlunary world of the aether. [4]
As theorized by Isaac Newton and Christiaan Huygens, [3]: 4 the Earth is flattened at the poles and bulged at the equator. Thus, geodesy represents the figure of the Earth as an oblate spheroid. The oblate spheroid, or oblate ellipsoid, is an ellipsoid of revolution obtained by rotating an ellipse about its shorter axis.