Scientific certainties of planetary life Author:Thomas Collyns Simon Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: in complete isolation. It has also been mentioned that a great many of the fixed stars of our group, as well as the one we call our sun, are found to have each a... more » distinct orbitual movement of its own, and that now all stars are supposed to have such, to which it is difficult as well as unnecessary to assign any other centre than the common one of the whole group; and this, notwithstanding the ordinary impression, need not by any means or in any case, be either a self- luminous or an opaque body—either a visible one or one invisible; for we know that the laws of gravitation do not require or even admit of this; we know that all the materials, for instance, that enter into the composition of the earth are attracted, not to any one definite portion of the internal substance, but to a mathematical point at the centre, which constitutes the centre of gravity to the whole mass. Now further : Our telescopes show us a great number of the stars of our own group that have other immensely distant bodies revolving round each of them, precisely in the same way as we see the planets of our system revolving round our sun; and in periods sometimes greater, sometimesless than the greater periods of our system. These distant bodies are thus therefore carried, in their attendance upon their suns, around the general centre of our firmament, Justin the same way as the planets of our system are carried with our sun around the same common centre, and not very unlike the way in which our moon is carried round our sun in her attendance upon the earth. This is peculiarly observable in what are called the binary systems; in most of which it is placed beyond all doubt that stars not only can act but do act as suns or central forces to planets exactly in the same way as our sun does. Whether the planets of...« less