If we observe the sky without being seduced by what passes for modern knowledge, it should be clear to the meanest intelligence that all objects in the universe revolve around the earth. They are pasted on an enveloping screen which keeps going round. Its axis of rotation runs through the pole star. We see different parts of the screen from different places on the earth. Those in India cannot see the Southern Cross; those in Mauritius cannot see the Pole Star.
Well, that cannot be quite right, for some objects change their positions with respect to one another. The moon is particularly wayward. It runs faster than the others; every thirty days it comes back to the position it started from.
And then, all the objects sway around the equator; they amble north and south. In summer they all move north, in winter south. A few are even more wayward. Some, such as Mercury and Venus, race ahead for some time and then retrace their steps. Others, such as Jupiter and Saturn, similarly accelerate and decelerate, but over longer periods. These objects wander across the sky in a rather disorderly way.
Aristotle (384-322 BC), a student of Plato, systematized this picture. The earth was in the middle of a shell ' the firmament. Above the firmament were three circles housing fire, which heated the earth, water, which rained on earth, and air, which buffeted the earth with hurricanes. Beyond the three elements moved the planets; the sun was the earth's fourth planet, beyond the moon, Mercury and Venus. Beyond them were the stars. They all moved in imperfect circles, like ellipses.
Scholars who followed Aristotle made observations of the movement of heavenly bodies and tried to fit them to circular models, but there were discrepancies between the two. They made more sophisticated models, which are however lost. Finally, Claudius Ptolemy (85-165), who lived in Roman Egypt, wrote a huge mathematical text which has come down to us in the Latin translation of the Arabic translation of the original Greek, called Almagest. His theory was that all heavenly bodies went round the earth, but that the centre of rotation ' called the equant ' was slightly displaced from the earth, so they came closer to the earth sometimes and sometimes receded. And they themselves revolved in small circles, called epicycles, around a point which revolved round the earth. When even epicycles failed to fit observations, Ptolemy revolved plants in epicycles which themselves revolved around points going round in epicycles around a point rotating round the earth. He kept adding epicycles until his model came close to observations.
Ptolemy's theory survived for 1,400 years. It reigned not just because it fitted facts, but because it was consecrated in the Bible; the ninety-third Psalm said, 'Thou hast fixed the Earth immovable and firm, Thy throne firm from of old; for all eternity Thou art God.' That settled all doubt. The church ruled people's hearts, and the lands it owned and the tax it collected gave it control on their livelihoods. So geocentricity was orthodoxy.
Then in 1489, Lucas Watzenrode became bishop of Varmia, which was then in East Prussia; it is now a part of Russia, which took it after it defeated Germany in World War II and pushed it westwards. As was normal in that age, he appointed his 16-year-old nephew, Nicolaus, canon of his cathedral in Frauenburg. Nicolaus did not have to do much, but it gave him income. So he took off for Italy. He studied law in Bologna and medicine in Padua and, after seven years of perambulation, became doctor of canonic law from Ferrara. Then he returned to his job, started collecting tithes from tenant farmers of the church, and eventually set up home in the tower of the wall facing the Frauenburg cathedral.
From the 50-ft tower he had plenty of opportunity to watch stars. He started recording their positions, and matching them to Ptolemy's circles. On doing this, he found that the point near the earth around which everything revolved was in the same place as the sun. If he assumed that it was the sun, it enabled him to dispense with many of Ptolemy's epicycles.
Nicolaus was faced with a dilemma. On the one hand, he had made a fantastic discovery which should have been publicized from the rooftop. On the other hand, what he now believed went against the Bible, and could expose him to the charge of heresy. So he chose to keep quiet. In any case, there were no journals of astronomy in his time to publish his theory; and publishing a book would have been a mammoth undertaking. Movable type printing had been invented only a century earlier ' Johannes Gutenberg had set the Bible to type only in 1455. There were few printers; none of them was within a few hundred miles of him. Science was done very differently in that age. A scholar gathered a few students around him and lectured to them; students travelled from teacher to teacher to gather knowledge. There were universities with libraries; but few other than dedicated scholars collected books. Those who did, treasured them; they read them again and again, and made copious notes in their margins.
Then one scholar in Wittenberg, Georg Joachim Rheticus, heard about the strange theories of Nicolaus (I may as well reveal his last name ' Copernicus), and decided to go and learn about them from the horse's mouth. He arrived in Frauenberg in 1538.
He found that Copernicus had written up his theory in a huge tome full of observation and mathematics (it started with the admonition: 'Those who do not know geometry may not enter here'). Fascinated by Copernicus's heliocentric theory, he wrote off a 70-page introduction called 'Narratio Prima' (First Description), and got it printed in nearby Danzig. It was an immediate sensation; next year it was reprinted in Basel. It took him two years, but he finally persuaded Copernicus to let him take his manuscript for publication by Petreius, a famous academic printer in Wittenberg. In 1543, it was published under the title, Nicolai Copernici Torinensis De Revolutionibus Orbium Coelestium Libri Sex (Six Books on the Revolutions of the Heavenly Spheres by Nicolaus Copernicus of Torin).
Copernicus was 70 when De Revolutionibus was published; he died soon after. Others became more famous for their heliocentric views, particularly Galileo, because he was persecuted for heresy, and Kepler, because of his three elegant laws. Arthur Koestler, in The Sleepwalkers, his popular 1959 book on early astronomers, called Copernicus's De Revolutionibus the book nobody read. Incensed by that dismissal, Owen Gingerich, research professor of astronomy and history of natural sciences in Harvard, spent a lifetime tracing all copies of De Revolutionibus and finding out who had owned and read them. In the process, he became an expert on the book, was often consulted by antiquarian book dealers on the quality and provenance of copies they handled, and was called to court as expert. He tells the story of his revolutionocentric career in The Book Nobody Read: One Man's Quest to Visit Every Surviving Copy of One of the World's Great Books (Arrow).