Heavenly sphere, definition, and study. A-Z index of Cognitio.

The celestial sphere is an imaginary sphere of the arbitrary radius on whose surface all the stars are projected. The celestial sphere is called geocentric, if it has entered the center of the earth, local if it has the eye of the observer, heliocentric if it has the center of the Sun.Sun, definition and study. A-Z index of Cognitio.

The origin of this ray arbitrariness lies in the fact that beyond a certain distance we are no longer able to visually assess the distance of the bodies, so the stars seem all the same distance. During the apparent daytime motion of the stars, only two points of the sky, antipodal, remain intact: they are the celestial poles. The celestial sphere, then, seems to rotate itself around an axis passing through the poles, called heavenly axis. Since the visible stars and their positions on the celestial vault vary with the observer’s position on Earth, it is useful to refer to the vertical of the site and the astronomical horizon of the observer.Earth, definition and study. A-Z index of Cognitio.

The concept of “celestial sphere” dates back to the ancient Ptolemaic system, prior to the Copernican Revolution, in which it was believed that the stars and the planets were really fixed on orbits of different magnitude, located in one another and having Earth as the center.Ptolemaic system, definition and study. A-Z index of Cognitio.

The motion of celestial bodies such as the Sun or the Moon was due to the rotating movement of these spheres, moving by dragging them with them. Moon, definition and study. A-Z index of Cognitio.

It was in any case transparent and invisible balls, composed of an ethereal substance, that is, a crystalline element of a spiritual nature, not present in the sublunar world. Pythagoras saw in them mathematical relationships that produced heavenly harmony, the so-called “ball music”, imperceptible to the human ear, capable of affecting the quality of earthly life.

Heavenly sphere, definition, and study. A-Z index of Cognitio.

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Heavenly sphere, definition and study. A-Z index of Cognitio.