Seven Heaven

Il più antico calcolatore analogico della storia è conosciuto col nome di Calcolatore o Macchina di Antikythera, e risale al I secolo a.C..
Si tratta di un complesso planetario, mosso da ruote dentate, che serviva per calcolare il sorgere del sole, le fasi lunari, i movimenti dei 5 pianeti allora conosciuti, gli equinozi, i mesi e i giorni della settimana.
Ad un primo esame delle caratteristiche del Calcolatore di Antikythera si poteva pensare ad una macchina “fuori dal tempo”: gli archeologi concordavano nell’affermare che in quel tempo non era possibile produrre apparecchiature di tale complessità cinematica.

Oggi sul settimanale inglese Nature Tony Freeth e Mike G. Edmunds, della University of Cardiff, e il team di studiosi Greci, Inglesi e Americani, che da diverso tempo studia il manufatto hanno sciolto ogni dubbio. Hanno usato la tomografia tridimensionale a raggi X per ottenere immagini ad alta definizione delle parti sotto la superficie del meccanismo.

The Antikythera Mechanism is a unique Greek geared device, constructed around the end of the second century bc. It is known that it calculated and displayed celestial information, particularly cycles such as the phases of the moon and a luni-solar calendar. Calendars were important to ancient societies for timing agricultural activity and fixing religious festivals. Eclipses and planetary motions were often interpreted as omens, while the calm regularity of the astronomical cycles must have been philosophically attractive in an uncertain and violent world. Named after its place of discovery in 1901 in a Roman shipwreck, the Antikythera Mechanism is technically more complex than any known device for at least a millennium afterwards. Its specific functions have remained controversial because its gears and the inscriptions upon its faces are only fragmentary. Here we report surface imaging and high-resolution X-ray tomography of the surviving fragments, enabling us to reconstruct the gear function and double the number of deciphered inscriptions. The mechanism predicted lunar and solar eclipses on the basis of Babylonian arithmetic-progression cycles. The inscriptions support suggestions of mechanical display of planetary positions now lost. In the second century bc, Hipparchos developed a theory to explain the irregularities of the Moon’s motion across the sky caused by its elliptic orbit. We find a mechanical realization of this theory in the gearing of the mechanism, revealing an unexpected degree of technical sophistication for the period.

[From the following article:Decoding the ancient Greek astronomical calculator known as the Antikythera Mechanism
T. Freeth, Y. Bitsakis, X. Moussas, J. H. Seiradakis, A. Tselikas, H. Mangou, M. Zafeiropoulou, R. Hadland, D. Bate, A. Ramsey, M. Allen, A. Crawley, P. Hockley, T. Malzbender, D. Gelb, W. Ambrisco and M. G. Edmunds
Nature 444, 587-591(30 November 2006)
doi:10.1038/nature05357 ]

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