Comets, bodies which in many points seem allied to meteorites, probably have, as we shall shortly see, a similar origin. II. _Motion of the Stars; how of such different velocities, and always in straight lines._ It will be only when the two bodies, coming from contrary directions, collide with equal momentum that the entire motion will be stopped. But in the case of stellar masses moving, as it were, at random in every direction this is a condition which will but rarely occur. Accordingly, in most cases the resulting stars will have more or less motion. In short, the stars should, according to the theory, be moving in all directions and with all varieties of velocity. Further, it follows that these motions ought to be in perfectly straight lines, and not in definite orbits of any kind. So far as observation has yet determined, all these conditions seem to be fulfilled. Sometimes it will happen that the two bodies will strike each other obliquely. In this case the resulting star, both as to the direction and velocity of its motion, will, to a large extent, be the resultant of the two concurrent forces. III. _Motion of the Stars not due to their Mutual Attractions._ According to the theory the absolute motion of the stars is due, not to the influence of gravity, but to motions which originally belonged to the two component masses out of which the star arose; motion regarding the origin of which science can no more inform us than it can regarding the origin of the masses themselves. There is strong presumptive evidence that the motion of the stars is due to this cause. We know that there are stars which have a far greater velocity than can result from gravitation, such, for example, as the star 1830 Groombridge, which has a velocity of 200 miles per second. Suppose, with Professor Newcomb, that the number of stars belonging to the universe amounts to 100,000,000, and that these have, on the average, five times the mass of the sun, and are spread out in a layer across which light requires 30,000 years to pass. Then computation shows that, unless the attractive power of the whole were sixty-four times greater than it really is, it could not have conferred on Groombridge the motion which it possesses, or arrest it in its onward course.[7] We are therefore forced, as Professor Newcomb remarks, to one of two alternatives, viz.: “Either the bodies which compose our universe are vastly more massive and numerous than telescopic examination seems to indicate, or 1830 Groombridge is a runaway star, flying on a boundless course through infinite space, with such momentum that the attraction of all the bodies of the universe can never stop it.” [Footnote 7: Newcomb’s _Astronomy_, p. 487, English edition, 1878.]