Analog October 1985 [antikvár]

iditaidMORE THAN ONE WAY Stdnley SchmidtThe first astronomy book I can remember reading contained two pages on the origin of the Sotar System, admitting that nobody really knew how it happened but outlining two general types of theories which had been proposed. One was the old Kant-Laplace "nebular hypothesis," in which the Sun was formed by the gravitational contraction of a mass of gas. Because of the conservation of angular momentum, the mass would tend to spin faster as its volume shrank, and if it sped up enough it might fling equatorial matter off into space, there to coalesce into planets. The other model in my old book was the Cham-berlin-Moulton theory, in which the material for planets was pulled from the4Sun by the tidal attraction of another star passing nearby. The book freely admitted that both theories, in the forms they had then, failed to explain a good deal that needed explaining.However, most subsequent models are recognizable descendants of one or the other of these. The question of which way it actually happened has long been a subject of more than local interest because of the implications the answer might have for the abundance of "solar" systemsand the things that might inhabit them, if what happened here was some version of the Kant-Laplace model, planet formation would seem to be a normal part of star formation, and the universe would teem with planets and life. But if it took an event as specialAnalog Science Fiction!Science Fact