Planets and Planetarians [antikvár]

INTRODUCTIONwhen ten years ago man stepped on the moon, even the sceptics must have sensed that the step was only the start of man's march into the realm of planets. An extraordinary realm, to be sure, which unlike things and processes on earth, appeared to man since ancient times as the realm of exactness. The regularity and precision of the motion ot planets became ultimately, in the hands of Newton, the clue to a physics which has not ceased unfolding more and more of the exactness that after all rules this globe of ours as well. One of the great triumphs of that physics was the demonstration by Laplace that the system of which our earth is a principal member has a very large measure of stability, though not an absolute one. The solar system, like anything else, is a child of time. It was born and has grown into its present frame which is destined to collapse in the long run. Indeed, it was a famous hypothesis submitted by Laplace that first assured scientific respectability to an evolutionary approach to the system of planets. In almost two centuries following the first publication of Laplace's nebular hypothesis, and especially during the last three generations, much effort has been spent on elucidating the history of the planetary system. That history is still to be traced out in an essentially satisfactory manner.Such may seem relatively little progress but even less has been made in what should seem a far easier task, namely, the historiography of those efforts aimed at tracing out that history, or the history of theories of the origin of planetary systems. In fact, there seems to exist on this topic no monograph sufficiently detailed and steeped in the reading of the original documents. While some essay-reviews of the state of the art covering the last few decades are of distinct help to the historian for a primary orientation, he should be rather suspicious of accounts concerning the first three decades of this century. Suspicion should yield to distrust as he tries to orient himself from texts and histories of astronomy about the 19th-century part of the story. Finally, he should not be unwilling to take the attitude of plain disbelief with respect to most secondary information about what had been really proposed during the 18th and 17th centuries on the quesdon. This sad record is largely the making of those who in proposing theories on the evoludon of the solar system offered a review of what had been said previously, and of those, also mostly scientifically trained men, who drafted histories of such theories. Their cavalier handling of the facts of scientific history may seem a small matter. Yet a reasonably correct presentation of those facts is of paramount importance with respect to the cultural impact of science. A sciendfic explanation influences cul-