{The Cosmogony of Laplace}

If now, in fancy, we select any one of the agglomerations considered as in their primary stages throughout the Universal sphere, and suppose this incipient agglomeration to be taking place at that point where the centre of our Sun exists – or rather where it did exist originally; for the Sun is perpetually shifting his position – we shall find ourselves met, and borne onward for a time at least, by the most magnificent of theories – by the Nebular Cosmogony of Laplace: – although ›Cosmogony‹ is far too comprehensive a term for what he really discusses – which is the constitution of our solar system alone – of one among the myriad of similar systems which make up the Universe Proper – that Universal sphere – that all-inclusive and absolute Kosmos which forms the subject of my present Discourse.

Confining himself to an obviously limited region – that of our solar system with its comparatively immediate vicinity – and merely assuming – that is to say, assuming without any basis whatever, either deductive or inductive – much of what I have been just endeavoring to place upon a more stable basis than assumption; assuming, for example, matter as diffused (without pretending to account for the diffusion) throughout, and somewhat beyond, the space occupied by our system – diffused in a state of heterogeneous nebulosity and obedient to that omniprevalent law of Gravity at whose principle he ventured to make no guess; – assuming all this (which is quite true, although he had no logical right to its assumption) Laplace has shown, dynamically and mathematically, that the results in such case necessarily ensuing, are those and those alone which we find manifested in the actually existing condition of the system itself.

To explain: – Let us conceive that particular agglomeration of which we have just spoken – the one at the point designated by our Sun's centre – to have so far proceeded that a vast quantity of nebulous matter has here assumed a roughly globular form; its centre being, of course, coincident with what is now, or rather was originally, the centre of our Sun; and its periphery extending out beyond the orbit of Neptune, the most remote of our planets: – in other words, let us suppose the diameter of this rough sphere to be some 6000 millions of miles. For ages, this mass of matter has been undergoing condensation, until at length it has become reduced into the bulk we imagine; having proceeded gradually, of course, from its atomic and imperceptible state, into what we understand of visible, palpable, or otherwise appreciable nebulosity.

Now, the condition of this mass implies a rotation about an imaginary axis – a rotation which, commencing with the absolute incipiency of the aggregation, has been ever since acquiring velocity. The very first two atoms which met, approaching each other from points not diametrically opposite, would, in rushing partially past each other, form a nucleus for the rotary movement described. How this would increase in velocity, is readily seen. The two atoms are joined by others: – an aggregation is formed. The mass continues to rotate while condensing. But any atom at the circumference has, of course, a more rapid motion than one nearer the centre. The outer atom, however, with its superior velocity, approaches the centre; carrying this superior velocity with it as it goes. Thus every atom, proceeding inwardly, and finally attaching itself to the condensed centre, adds something to the original velocity of that centre – that is to say, increases the rotary movement of the mass.