ay reasonably be included among the probable abodes
of life.

In order to form such judgments each planet must be examined by itself,
but first it is desirable to glance at the planetary system as a whole.
To do this we may throw off, in imagination, the dominance of the sun,
and suppose ourselves to be in the midst of open space, far removed both
from the sun and the other stars. In this situation it is only by
chance, or through foreknowledge, that we can distinguish our sun at
all, for it is lost among the stars; and when we discover it we find
that it is only one of the smaller and less conspicuous members of the
sparkling host.

We rapidly approach, and when we have arrived within a distance
comparable with that of its planets, we see that the sun has increased
in apparent magnitude, until now it enormously outshines all the other
stars, and its rays begin to produce the effect of daylight upon the
orbs that they reach. But we are in no danger of mistaking its apparent
superiority to its fellow stars for a real one, because we clearly
perceive that our nearness alone makes it seem so great and
overpowering.

And now we observe that this star that we have drawn near to has
attending it a number of minute satellites, faintly shining specks, that
circle about it as if charmed, like night-wandering insects, by its
splendor. It is manifest to us at the first glance that without the sun
these obedient little planets would not exist; it is his attraction that
binds them together in a system, and his rays that make them visible to
one another in the abyss of space. Although they vary in relative size,
yet we observe a striking similarity among them. They are all globular
bodies, they all turn upon their axes, they all travel about the sun in
the same direction, and their paths all lie very nearly in one plane.
Some of them have one or more moons, or satellites, circling about them
in imitation of their own revolution about the sun. Their family
relationship to one another and to the sun is so evident that it colors
our judgment about them as individuals; and when we happen to find, upon
closer approach, that one of them, the earth, is covered with vegetation
and water and filled with thousands of species of animated creatures, we
are disposed to believe, without further examination, that they are all
alike in this respect, just as they are all alike in receiving light and
heat from the sun.

This preliminary judgment,