The Man of Science

Abstract

The 1860s formed a crucial period in the development of astronomy. Since the scientific revolution of the seventeenth century, in which astronomy had played a major role, astronomers had been trying to build up a picture of the world based mainly on the accurate measurement of position and of changes in position. Newton had suggested that one force, gravitation, ruled the uni-verse, and throughout the eighteenth century astronomers had been concerned with substantiating his claim and extending it to as many cases of bodies in motion as possible. Since the planets and their satellites constituted the most obvious examples of motions amongst the celestial bodies, attention had at first been mainly confined to the solar system. By the nineteenth century, the most obvious difficulties in the reconciliation of Newtonian theory with the observations had been overcome; the prospect for astronomy seemed to be mainly one of increasing the accuracy of both observation and theory. In this respect, the state of astronomy in the first half of the nineteenth century might be compared with that of physics in the second half. However, just when the heroic age of classical astronomy seemed to be drawing to a close, a new aspect of astronomy began to blossom, the study of celestial bodies as physical objects rather than simply as dynamical ones. Of course, there had always been some work of this type in astronomy. When Galileo first used a telescope for astronomical observation, two of his earliest discoveries were the rugged nature of the Moon’s surface and the existence of dark spots on the Sun’s face. But this sort of observation had come to take a subordinate place to the main interest in positional work.