our sun. The inference seems forced upon us that the same process
of concentration which has gone on in the case of our solar
nebula has been going on in the case of other nebulae. The
history of the sun is but a type of the history of stars in
general. And when we consider that all other visible stars and
nebulae are cooling and contracting bodies, like our sun, to what
other conclusion could we very well come? When we look at Sirius,
for instance, we do not see him surrounded by planets, for at
such a distance no planet could be visible, even Sirius himself,
though fourteen times larger than our sun, appearing only as a
"twinkling little star." But a comparative survey of the heavens
assures us that Sirius can hardly have arrived at his present
stage of concentration without detaching, planet-forming rings,
for there is no reason for supposing that mechanical laws out
there are at all different from what they are in our own system.
And the same kind of inference must apply to all the matured
stars which we see in the heavens.

When we duly take all these things into the account, the case of
our solar system will appear as only one of a thousand cases of
evolution and dissolution with which the heavens furnish us.
Other stars, like our sun, have undoubtedly started as vaporous
masses, and have thrown off planets in contracting. The inference
may seem a bold one, but it after all involves no other
assumption than that of the continuity of natural phenomena. It
is not likely, therefore, that the solar system will forever be
left to itself. Stars which strongly gravitate toward each other,
while moving through a perennially resisting medium, must in time
be drawn together. The collision of our extinct sun with one of
the Pleiades, after this manner, would very likely suffice to