may happen to the solar system from without, and is of the nature of an unforeseen catastrophe. Our Sun might, as we remarked, be run into. For so far as we know at present the stars are moving among themselves without any too careful regard for one another. The swarm may be circling a central Sun as André states, but the individual stars behave more like the random particles of a gas with licensed freedom to collide; whereas we may liken the members of the solar system to molecules in the solid state held to a centre from which they can never greatly depart. Their motions thus afford a sense of security lacking in the universe at large.
Such an accident, a collision actual or virtual with another sun, would probably occur with some dark star; of which we sketched the ultimate results in our first chapter. The immediate ones would be of a most disastrous kind. For prefatory to the new birth would be the dissolution to make such resurrection possible. Destruction might come direct, or indirectly through the Sun. For though the Sun would be the tramp's objective point, we might inadvertently find ourselves in the way. The choice would be purely academic; between being powdered, or deorbited and burnt up.
So remote is this contingency that it need cause us no immediate alarm, as I carefully pointed out. But so strong is the instinct of self-preservation and so pleasur-
