(Vol. ix., p. 36.)
It is certainly an uncomfortable idea to suppose that the asteroids are the
fragments of a former world, perhaps accompanied with satellites which have
been scattered either by internal convulsion or external violence. By
looking into the constitution and powers contained within our own earth, we
know that the means are not wanting to rend us asunder under the combined
effects of volcanic action, intense heat, and water, meeting deep within
the substance of the earth under great pressure.
However, there is much to be said against the theory of Olbers,
notwithstanding its plausibility. The distance between the internal
asteroid Flora, and the external one Hygeia, exceeds ninety millions of
miles; or nearly the distance between the earth and the sun. The force
which could shatter a world into fragments, and drive them asunder to such
an extent, must indeed be tremendous.
Mr. Hind has drawn attention to the singular fact, that the asteroids
"appear to separate the planets of small mass from the greater bodies of
the system, the planets which rotate on their axes in about the same time
as our earth from those which are whirled round in less than half that
time, though of ten times the diameter of the earth and," he continues, "it
may yet be found that these small bodies, so far from being portions {130}
of the wreck of a planet, were created in their present state for some wise
purpose, which the progress of astronomy in future ages may eventually
unfold."
One thing I think is certain, that no disruption of a world belonging to
our system could take place without producing some perceptible effect upon
every other member of the system. The single centre of attraction being
suddenly diffused and spread abroad into many smaller ones, at variable
distances, must produce a sudden sway and alteration of position in all the
other planets, and to a certain extent, derange their respective economies.
From this some striking changes would necessarily arise, such as in the
length of their respective periods of revolution, the amount of light and
heat, and other physical conditions. Certain geological phenomena should be
found to confirm such a change, if these suppositions be true.
As far as the theological part of the question is concerned, it is, I
should think, opposed to Olbers' theory. Human intellect can scarcely
conceive the necessity for the utter breaking up of a globe, even for the
most grievous amount of sin. A more merciful dispensation was granted to
our earth in the deluge; and the Power which removed all but eight lives
from the earth could have equally removed the eight also, without
destroying the integrity of the globe. It is as easy, and far more
reasonable I think, to suppose, that the same Power which gave to Saturn a
satellite nearly equal in size to Mars, should throw a cluster of minute
planetoids into the space which, according to Bodes' empirical law, should
have been devoted to one planet of larger dimensions.
Whilst addressing you on astronomical subjects, I would beg leave to offer
a few remarks upon Saturn, which I have not observed in any work on
astronomy which I have yet consulted. This planet, with its satellites,
appear to exhibit a close resemblance to the solar system, just as if it
were a model of it.
Besides his rings, Saturn is attended by eight satellites, so far as is at
present known. The names of the satellites in their order from the body of
the planet, are 1. Mimas, 2. Euceladus, 3. Tethys, 4. Dione, 5. Rhea, 6.
Titan, 7. Hyperion, 8. Japetus. If we place them in a list in their order,
and overagainst each place the names of the planets in their order from the
sun, certain parallelisms will appear:
1. Mimas 1. Mercury.
2. Euceladus 2. Venus.
3. Tethys 3. Earth.
4. Dione 4. Mars.
5. Rhea 5. Asteroids.
6. Titan 6. Jupiter.
7. Hyperion 7. Saturn.
8. Japetus 8. Uranus.
The relative magnitudes and relative positions of these bodies correspond
in many points, I believe, so far as is at present known. Titan, like
Jupiter, is the largest of his system; being but little less in size than
the primary planet Mars. The next in magnitude is Japetus. Rhea is supposed
to be of considerable size. The four inner ones are smaller than the
others. Sir William Herschell considered that Tethys was larger than
Euceladus, and Euceladus larger than Mimas. Dione and Hyperion have not yet
been well estimated. These dimensions, if correct, correspond in many
points with those of the planets. The first three satellites revolve in
orbits of less diameter than that of our moon. The orbit of Dione, the
fourth satellite, is almost precisely at the same distance from its primary
as the moon is from the earth. As if to carry out the parallelism to the
utmost, the zodiacal light of the sun has often been compared to the ring
of Saturn.
One remark it would appear arises out of these observations, viz. that the
laws of attraction and gravitation seem to require, for the proper
regulation of the whole system, that where a number of bodies of various
sizes revolve round one common centre, the larger body should revolve at a
certain relative distance from that centre. Thus Titan, like a huge
pendulum, seems to sway and maintain the regularity of the minor system,
just as Jupiter may be imagined to do in the great one.
I must not intrude too far on your valuable space, but there remain some
interesting points for discussion in the Saturnian system.