Big Bang. Simon Singh

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СКАЧАТЬ into Latin, the Almagest was his most significant achievement.

      Thanks to the efforts of Gerard and other translators, European scholars were able to reacquaint themselves with the writings of the past, and astronomical research in Europe was reinvigorated. Paradoxically, progress became stifled, because there was such reverence for the writings of the ancient Greeks that nobody dared to question their work. It was assumed that the classical scholars had mastered everything that could ever be understood, so books such as the Almagest were taken as gospel. This was despite the fact that the ancients had made some of the biggest blunders imaginable. For example, the writings of Aristotle were considered sacred, even though he had stated that men have more teeth than women, a generalisation based on the observation that stallions have more teeth than mares. Although he was married twice, Aristotle apparently never bothered to look into the mouth of either of his wives. He might have been a superlative logician, but he failed to grasp the concepts of observation and experimentation. The irony is that scholars had waited for centuries to recover the wisdom of the ancients – and then they had to spend centuries unlearning all the ancients’ mistakes. Indeed, after Gerard’s translation of the Almagest in 1175, Ptolemy’s Earth-centred model of the universe continued to survive intact for another four hundred years.

      In the meantime, however, a few minor criticisms did emerge from such figures as Alfonso X, King of Castile and León (1221—84). Having made Toledo his capital, he instructed his astronomers to draw up what became known as the Alphonsine Tables of planetary motion, based partly on their own observations and partly on translated Arabic tables. Although he was a strong patron of astronomy, Alfonso remained resolutely unimpressed with Ptolemy’s intricate system of deferents, epicycles, equants and eccentrics: ‘If the Lord Almighty had consulted me before embarking upon Creation, I should have recommended something simpler.’

       Table 2

      This table lists various criteria against which the Earth-centred and Sun-centred models could be judged, based on what was known in the first millennium AD. The ticks and crosses give crude indications of how well each theory fared in relation to the seven criteria, and a question mark

Criterion	Earth-centred model	Success
1. Common sense	It seems obvious that everything revolves around the Earth
2. Awareness of motion	We do not detect any motion, therefore the Earth cannot be moving
3. Falling to the ground	The centrality of the Earth explains why objects appear to fall downwards, i.e. objects are being attracted to the centre of the universe
4. Stellar parallax	There is no detection of stellar parallax, absence of which is compatible with a static Earth and a stationary observer
5. Predicting planetary orbits	Very close agreement — the best yet
6. Retrograde paths of planets	Explained with epicycles and deferents
7. Simplicity	Very complicated – epicycles, deferents, equants and eccentrics

Criterion	Sun-centred model	Success
1. Common sense	It requires a leap of imagination and logic to see that the Earth might circle the Sun
2. Awareness of motion	We do not detect any motion, which is not easy to explain if the Earth is moving
3. Falling to the ground	There is no obvious explanation for why objects fall to the ground in a model where the Earth is not centrally located
4. Stellar parallax	The Earth moves, so the apparent lack of stellar parallax must be due to huge stellar distances; hopefully parallax would be detected with better equipment
5. Predicting planetary orbits	Good agreement, but not as good as in the Earth-centred model
6. Retrograde paths of planets	A natural consequence of the motion of the Earth and our changing vantage point
7. Simplicity	Very simple – everything follows circles

      Then, in the fourteenth century, Nicole d’Oresme, chaplain to Charles V of France, openly stated that the case for an Earth-centred universe had not been fully proved, although he did not go as far as saying that he believed it to be wrong. And in fifteenth-century Germany, Cardinal Nicholas of Cusa suggested that the Earth is not the hub of the universe, but he stopped short of suggesting that the Sun should occupy the vacated throne.

      The world would have to wait until the sixteenth century before an astronomer would have the courage to rearrange the universe and seriously challenge the cosmology of the Greeks. The man who would eventually reinvent Aristarchus’ Sun-centred universe was christened Mikolaj Kopernik, but he is СКАЧАТЬ