say.

In the case of the outer planets the answer to our question must
be in the negative. It now seems likely that Jupiter is a body
very much like our sun, only that the dark portion is too cool to
emit much, if any, light. It is doubtful whether Jupiter has
anything in the nature of a solid surface. Its interior is in all
likelihood a mass of molten matter far above a red heat, which is
surrounded by a comparatively cool, yet, to our measure, extremely
hot, vapor. The belt-like clouds which surround the planet are due
to this vapor combined with the rapid rotation. If there is any
solid surface below the atmosphere that we can see, it is swept by
winds such that nothing we have on earth could withstand them.
But, as we have said, the probabilities are very much against
there being anything like such a surface. At some great depth in
the fiery vapor there is a solid nucleus; that is all we can say.

The planet Saturn seems to be very much like that of Jupiter in
its composition. It receives so little heat from the sun that,
unless it is a mass of fiery vapor like Jupiter, the surface must
be far below the freezing-point.

We cannot speak with such certainty of Uranus and Neptune; yet the
probability seems to be that they are in much the same condition
as Saturn. They are known to have very dense atmospheres, which
are made known to us only by their absorbing some of the light of
the sun. But nothing is known of the composition of these
atmospheres.

To sum up our argument: the fact that, so far as we have yet been