Introduction

Newton's mechanics fundamentally altered man's vision of the universe, affecting the way we conceive of the physical world. Others before him, such as Copernicus (1473–1543), Kepler and Galileo (1564–1642), had helped clear a long trail of false starts and half truths that they had inherited. Some of the earliest physical “laws” turned out to be utterly wrong. Aristotle, for example, made pronouncements coming from pure thought that were largely untested by physical experiment, and so did Plato (ca. 428–348 bce), who incorrectly concluded that planets travel in perfect circles. Even during the early decades of the Renaissance such teachings were considered gospel. Plato's ancient dictum “Save the circles” became so much a part of Kepler's motivating inspiration that when he finally did discover the truth, that planets travel along ellipses, the disillusioned scientist regarded it as a sad commentary about our universe.

We've become much wiser through the ages, and now know that science has two sides, strategic and tactical. That is, science requires both the armchair for thought and the laboratory for data-collecting. Nicolaus Copernicus realized this and made careful observations of the heavens, culminating in his life's great opus, De revolutionibus (On the Revolutions). Galileo eventually embraced the Copernican model and then openly sup- ported it. This created great consternation in the Church, for it was angered yet had to tread carefully: Galileo was articulate, brilliant and immensely popular.