Lazarus Secretarius [antikvár]

Greek scientific thinking first developed in the Ionian schools, mainly in Miletus in Asia Minor. Thales of Miletus, one of the founders of Greek nature philosophy t hought the Earth to be disk-shaped, resting upon something, maybe the world ocean, by its weight. However, his disciple, Anaximander, alsó of Miletus, already believed that the Earth was floating in space "at an equal distance from everything". The Pythagoreans were the first to say that the Earth was spherical, the sphere being the most perfect of all shapes. This was their great achievement. Pythagorean numerology, the effort to construct a world out of numbers, however, soon lost credit. Zeno's aporias and later the diagonal of the square raised problems to which there appeared to be no solution. It turnéd out that if the number one is given for the sides of a square, there is no number which would describe the square's diagonal (yjl being irrational). The fact that the thinking of the Pythagoreans ended up in irrationalism probably hindered the spreading of the view that the Earth was a sphere. After the Athenian and Italian schools the scene where the brilliance of the Hellenic spirit shone for the last time was the town of Alexandria. The Hellenistic period of Alexandria was marked by the Lyceum moving there from Athens, the foundation of the Museion, and by names like Euclid-whose Elements served as a standard textbook up to the turn of the 20th century-or Aristarchus, Eratosthenes and Hipparchus. Aristarchus of Samos pointed out that the Sun is considerably larger than the Earth, and the proportion of their diameters is more than 19 to 3. Moreover, as mentioned by Archimedes, he was convinced that the Sun and the fixed stars did not move, and it was the Earth which moved aröund the Sun on a circular orbit. It is a pity that the work of Aristarchus is lost and his arguments are no longer known. The fact that the rotation axis of the Earth does not circle the sky year by year as the orbiting Earth would require seemed a strong argument against Aristarchus's views. It was, however, one to which Aristarchus himself found the right answer: the Earth's orbit is negligibly small compared to the distance of the fixed stars; their relation is like the relation of the sphere's centre to its surface. It was in the work of Ptolemy, one of the last great scientists of the Hellenistic period of Alexandria, that the knowledge of the Antiquity about the Earth and the Universe found its final synthesis. His two most important works were the Zúvra&cr and rewypoi(poKri öq>f\yr\aia. The first systematically expounds the geocentric world view, mainly on the basis of Hipparchus's measurements, the deferents and epicycles; the second one maps out the Earth which Ptolemy regarded to be spherical. Since the surface of the sphere cannot be expressed as a pláne, Ptolemy supplied his maps, covering the whole world then known, with the grid of geographic coordinates which he created on the basis of the theory of projections, and determined the coordinates of several hundred geographical locations. A geocentric or heliocentric Universe and a disk-shaped or spherical Earth are different notions but they are closely connected. The Copernican Universe would be inconceivable without the concept of a spherical Earth. Both of Ptolemy's works were closely related to the evolution of the Copernican world view. Not long after. Ptolemy's death, the Edict of Milán (333 A.D.) adopted Christianity as the state religion of the Román Empire. The early Church did not take any definite position on the issue of the Universe and the disk-shaped or spherical Earth. The 3rd century Church father Origen was still a free thinker. At the beginning of the 5th century, however, St. Augustine, Bishop of Hippo, laid down the 5