The Salt Lake herald. [volume] (Salt Lake City [Utah]) 1870-1909, 1897-01-18

/ materials of which the earth is made.
| This is an instructive result. inaSmuch
as it shows US plainly that Jupiter must
/ be d globe of d totally different nature
from this earth on which we dwell.
The important fact to which our at
| tentiOn is thus directed may also be
emphasized in the following manner: II
/ can be shown that the earth is about
! five and one-half times as heavy as
/ globe of water would be which was
/ the same size as the earth. This result
is quite what might have been eX-
pected from the heavy character OF the
I rocks and the metals out Of which this
I globe has been built. But when we
make a similar calculation with gard
I to Jupiter we arrive at very 0iIer-
! ent result. The great planet IS. no
doubt, heavier than an~eQually large
globe of water, but it is not so heavy
as one and a half times Of such globes
This fact at once shows that the ma
terials of Jupiter cannot be at present
/ in the same physical state as are the
materials OF the earth. The very light
est Of terrestrial rocks. If formed into
d globe as big as Jupiter, would Ger
tainly be far heavier than the great
/ planet is actually found to be. We
are. therefore, forced TO the conclusion
that Jupiter is in some way or other a
very different body from our earth.
I LATEST DISCOVERIES REGARD
ING JUPITER'S COMPOSITION.
It first it might be supposed that the
/ great planet was built out OF some
materials not known to US on this
earth. and whose density is much be-
low that OF the actual elements out of
/ which our earth has been formed.
There was no doubt time when Such
d proposition if seriously made could
not have been easily refuted. But in
these latter days it is not possible to
contend that any member of the plan
etary system could be composed of
/ materials essentially different from
! those of which the earth is made. 1t
has been the triumph of modern
science TO have demonstrated by the
help of the SpectrOScOpe that the ele-
mentary substances of which the sun
and even the stars are constituted are
. essentially the same as the substances
of which our earth is composed. No
doubt the method of analysis which
announces this important result for
the sun and the stars, does not apply
/ exactly in the same manner to the
planets. It must be admitted that we
4 cannot assure ourselves by direct OBJ
/ serVatiOn that the planetary elements
are altogether the same as those on
4 the earth. To a certain extent, how
/ ever. the method is available even for
the planets, and it shows, for instance,
that Watery VapOr at least IS assured
I ~ present in the clouds surrounding
/ Jupiter The argument is, however,
/ sufficiently conclusive, for whenever
we have the opportunity of testing the
chemical nature of bodies elsewhere
in the universe, we invariably find
them to be constituted from the same
/ substance that we know on the earth.
1t follows that analogy forbids US to
suppose that there can be, to any eX-
tent elements in Jupiter different es-
fse,11 ioaG n
is formed
We may therefore take it for grant
/ ed that if chemists could obtain speci-
mems of Jupiter and take them into
/ their laboratories for examination. they
would find these specimens essentially
/ composed of those very same elements
with which they are already familiar
! in terrestrial chemistry. This being ad
mitted sc are now very close to the
explanation of the remarkable dispari-
~ between the bulk Of the giant planet
and its weight
/ JUPITER'S GREAT INTERNAL
HEAT.
There cannot be the least doubt that
Jupiter is very much hotter than the
earth. 1t must be understood that in
this statement I am not referring to
the heat derived from the sun. In so
!
F less heat than the earth, so that if
we We're only considering sun heat we
should find that Jupiter was much
{ colder than the earth. 1t can, indeed,
+ be shown that the share of sunbeams
which arrive at such distance as
/ that at which Jupiter is placed is only
about the 25th part of the share Of
sunbeamS which we enjoy. The heat
/ of Jupiter to which I now refer is of
quite a different kind. 1t is what is
known as internal heat.
We believe that the interior of the
earth is very hot, hotter indeed than
molten iron, though the temperature of
the surface OF cur globe is now but
little influenced by the internal heat.
on the other hand the sun is not only
/ extremely hot in the interior, but the
outer regions of the great luminary
are obviously in a state OF fierce mean
deScence. Let Us imagine the condi-
ton OF a globe somewhat intermediate
in condition between the earth and the
sun. Let Us suppose il hot enough at
the surface to transform any water
that might be present into steam,
though not hot enough to glow with
any visible light as a sunlike body. In
this way we might produce a globe
which would apparently possess the
same physical character as Jupiter. In
such q body the quantity of matter in
the VapCrOus form would swell the
bulk Of the globe in comparison with
that Of a colder globe Svhich might
contain quite as large an amount of
actual material In this consideration
we can no doubt find the reason why
Jupiter, though only 30 times as heavy
as the earth is certainly 1920 times as
big. Jupiter has certainly very much
more internal heat than our globe. The
outer parts Of the great planet con-
sist of layers of dense VapOr thou
sands of miles in thickness, which
have increased the bulk of Jupiter
enormously without adding to his
weight in anything like the same pro-
portion
These considerations viii explain the
peculiar aspect which Jupiter presents
TO the observer. It is obvious that in
the great planet the astronomer finds
before him an object of a widely diff
ferent character from the earth on
which he stands or from such bodies
as the moon and the planet Mars The
telescope shows the features on these |
objects TO be of permanent character /
The craters and mountains on the moon
are evidently solid and time reveals (
little or no change in them. 1t is per
haps not quite so true to say that the
features of Mars are permanent But
the fact that charts of Mars have been }