for
ten thousand years might gather some faint suggestion of an answer, or
he might not. All we can do is to seek for some hints by study and
comparison with other stars.

The stars are suns. To put it in another way, the sun is one of the
stars, and rather a small one at that. If the sun is moving in the way
I have described, may not the stars also be in motion, each on a
journey of its own through the wilderness of space? To this question
astronomy gives an affirmative answer. Most of the stars nearest to us
are found to be in motion, some faster than the sun, some more slowly,
and the same is doubtless true of all; only the century of accurate
observations at our disposal does not show the motion of the distant
ones. A given motion seems slower the more distant the moving body; we
have to watch a steamship on the horizon some little time to see that
she moves at all. Thus it is that the unsolved problem of the motion of
our sun is only one branch of a yet more stupendous one: What mean the
motions of the stars--how did they begin, and how, if ever, will they
end? So far as we can yet see, each star is going straight ahead on its
own journey, without regard to its neighbors, if other stars can be so
called. Is each describing some vast orbit which, though looking like a
straight line during the short period of our observation, will really
be seen to curve after ten thousand or a hundred thousand years, or
will it go straight on forever? If the laws of motion are true for all
space and all time, as we are forced to believe, then each moving star
will go on in an unbending line forever unless hindered by the
attraction of other stars. If they go on thus, they must, after
countless years, scatter in all directions, so that the inhabitants of
each shall see only a black, starless sky.

Mathematical science can throw only a few glimmers of light on the
questions thus suggested. From what little we know of the masses,
distances, and numbers of the stars we see a possibility that the more
slow-moving ones may, in long ages, be stopped in their onward courses
or brought into orbits of some sort by the attraction of their millions
of fellows. But it is hard to admit even this possibility in the case
of the swift-moving ones. Attraction, varying as the inverse square of
the distance, diminishes so rapidly as the distance increases that, at
the distances which separate the stars, it is small indeed. We could
not, with the mos