The Copernican Revolution:
It was right in the midst of these developments in the fifteenth century, that there came the first major break from the whole system of ancient thought. This was the work of Copernicus, who gave a clear and detailed explanation for the rotation of earth and other planets on their axis and their motion around a fixed sun which was at the centre. This model simplified astronomical calcuhtions, and also made them more precise. In such a model had been proposed by Greek astronomers like Aristarchus many centuries earlier. However, it was not given any importance because it ran counter to the established ideas of those times. This work of Cope~nicus was published in the very year of his death in 1543. Although his book attracted limited attention and there were objections to his model, his work-gave a great boost to further work by Galileo. We will talk about Galilee's work later in Sec. This was the first phase of what we now call the Scientific Revolution. In this phase, the old ways of thought were proving inadequate. By rejecting the old ideas, the men of Renaissance had cleared the grounds for new ideas of the succeeding century. In the use of science for practical purposes too, the Renaissance set the scene for. future developments. From now on science had become a necessity for profitable enterprises, trade and war.