Pleasant ways in science / by Richard A. Proctor.

  • Proctor, Richard A. (Richard Anthony), 1837-1888.
Date:
1878
Catalogue details

Licence: Public Domain Mark

Credit: Pleasant ways in science / by Richard A. Proctor. Source: Wellcome Collection.

    35/462 (page 23)
    cesses suggested by Laplace are in accordance with the now known laws of physics ? To begin with, the original nebulous mass extending to a distance exceeding the earth's distance from the sun more than thirty times (this being only the distance of Neptune), if we assign to it a degree of compres- sion making its axial diameter half its equatorial diameter, would have had a volume exceeding the sun's (roughly) about 120,000,000,000 times, and in this degree its mean density would have been less than the sun's. This would correspond to a density equal (roughly) to about one- 400,000th part of the density of hydrogen gas at atmospheric, pressure. To suppose that a great mass of matter, having this exceedingly small mean density, and extending to a distance of three or four thousand millions of miles from its centre, could under any circumstances rotate as a whole, or behave in other respects after the fashion attributed to the gaseous erabryon of the solar system in ordinary descriptions of the nebular hypothesis, is altogether inconsistent with correct ideas of physical and dynamical laws. It is abso- lutely a necessity of any nebular hypothesis of the solar system, that from the very beginning a central nucleus and subordinate nuclei should form in it, and grow according to the results of the motions (at first to all intents and purposes independent) of its various parts. Granting this state of things, we arrive, by considering the combined effects of accretion and contraction, at a process of development according fully as well as that ordinarily described with the general relations described by Laplace, and accounting also (in a general way) for certain peculiarities which are in no degree explained by the ordinary theory. Amongst these may specially be noted the arrangement and distribution of the masses within the solar system, and the fact that so far as spectroscopic evidence enables us to judge, a general similarity of structure exists throughout the whole of the system. Inquiring as to the significance of his discovery, Dr. Draper remarks that it seems rather difficult at first sight