= Paper =
the Greek notion of sphere is part of a process of continuity / rupture which goes back to Sumer. There, the cosmos becomes in astronomy the celestial sphere, known under two aspects: that of the theory where, although absent from the lexicon, we can deduce from two tangent circles which wrap it; and that of the practice where is used the hemispherical sundial, named scaphe by the Greeks; at the same time, the "totality" is, on the clay tablet, a perfect disk / ring. In Greece, the mathematical sphere, which assumes a perfect shape and acquires for the human thought a remarkable efficiency, also ensues from the vision of a cosmos influenced by Mesopotamia and feeds, in the diverse stages of its elaboration, contributions of the Babylonian astronomy.
