Newcomb: "At the present time we can only say that the nebular hypothesis is indicated by the general tendencies of the laws of nature, that it has not been proved to be inconsistent with any fact, that it is almost a necessary consequence of the only theory by which we can account for the origin and conservation of the sun's heat, but that it rests on the assumption that this conservation is to be explained by the laws of nature as we now see them in operation.
Newcomb, Popular Astronomy; Lick Observatory publications.
Newcomb, was used from 1882 to 'goo; and since then the value 8.80" has been employed, having been adopted at a Paris conference in 1896.1 Five fundamentally different methods of determining the distance of the sun have been worked out and applied.
From an investigation of all the observations upon Mercury and the other three interior planets, Simon Newcomb found it almost out of the question that any such mass of matter could exist without changing either the figure of the sun itself or the motion of the planes of the orbits of either Mercury or Venus.
Newcomb found an excess of motions in the perihelion of Mars amounting to about 5" per century.