without limit or stay, save that which is given
by its inability to grasp the unbounded.
The two Herschels have in succession made some other most
remarkable observations on the regions of space. They have found
within the limits of our astral system, and generally in its outer fields, a
great number of objects which, from their foggy appearance, are called
nebulae; some of vast extent and irregular figure, as that in the sword of
Orion, which is visible to the naked eye; others of shape more defined;
others, again, in which small bright nuclei appear here and there over
the surface. Between this last form and another class of objects, which
appear as clusters of nuclei with nebulous matter around each nucleus,
there is but a step in what appears a chain of related things. Then, again,
our astral space shews what are called nebulous stars,--namely,
luminous spherical objects, bright in the centre and dull towards the
extremities. These appear to be only an advanced condition of the class
of objects above described. Finally, nebulous stars exist in every stage
of concentration, down to that state in which we see only a common
star with a slight BUR around it. It may be presumed that all these are
but stages in a progress, just as if, seeing a child, a boy, a youth, a
middle-aged, and an old man together, we might presume that the
whole were only variations of one being. Are we to suppose that we
have got a glimpse of the process through which a sun goes between its
original condition, as a mass of diffused nebulous matter, and its
full-formed state as a compact body? We shall see how far such an idea
is supported by other things known with regard to the occupants of
space, and the laws of matter.
A superficial view of the astronomy of the solar system gives us only
the idea of a vast luminous body (the sun) in the centre, and a few
smaller, though various sized bodies, revolving at different distances
around it; some of these, again, having smaller planets (satellites)
revolving around them. There are, however, some general features of
the solar system, which, when a profounder attention makes us
acquainted with them, strike the mind very forcibly.
It is, in the first place, remarkable, that the planets all move nearly IN
ONE PLANE, corresponding with the centre of the sun's body. Next, it
is not less remarkable that the motion of the sun on its axis, those of the
planets around the sun, and the satellites around their primaries, {9}
and the motions of all on their axes, are IN ONE DIRECTION--namely,
from west to east. Had all these matters been left to accident, the
chances against the uniformity which we find would have been, though
calculable, inconceivably great. Laplace states them at four millions of
millions to one. It is thus powerfully impressed on us, that the
uniformity of the motions, as well as their general adjustment to one
plane, must have been a consequence of some cause acting throughout
the whole system.
Some of the other relations of the bodies are not less remarkable. The
primary planets shew a progressive increase of bulk and diminution of
density, from the one nearest to the sun to that which is most distant.
With respect to density alone, we find, taking water as a measure and
counting it as one, that Saturn is 13/32, or less than half; Jupiter, 1 1/24;
Mars, 3 2/7; Earth, 4 1/2; Venus, 5 11/15; Mercury 9 9/10, or about the
weight of lead. Then the distances are curiously relative. It has been
found that if we place the following line of numbers, -
0 3 6 12 24 48 96 192,
and add 4 to each, we shall have a series denoting the respective
distances of the planets from the sun. It will stand thus -
4 7 10 16 28 52 100 196 Merc. Venus. Earth. Mars. Jupiter. Saturn.
Uranus.
It will be observed that the first row of figures goes on from the second
on the left hand in a succession of duplications, or multiplications by 2.
Surely there is here a most surprising proof of the unity which I am
claiming for the solar system. It was remarked when this curious
relation was first detected, that there was a want of a planet
corresponding to 28; the difficulty was afterwards considered as in a
great measure overcome, by the discovery of four small planets
revolving at nearly one mean distance from the sun, between Mars and
Jupiter. The distances bear an equally interesting mathematical relation
to the times of the revolutions round the sun. It has been found that,
with respect to any two planets, the squares of the times
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