The Ocala evening star. [volume] (Ocala, Fla.) 1895-1943, 1907-12-13
THE EARTH'S INTERIOR
Our Planets Core Is Liquid, Yet
It's as Rigid as Steel.
UNDER ENORMOUS PRESSURE

NcIknef faoSK Ncf meIai OoGIC Rer7a n
There In the State In Which We See
II on the SurfEce-The Lava That
Breaks Through the Earth's Crust.
The idea that the interior OF the globe
Is composed Of flowing lava has long
since been abandoned. but the picture
that modern science Offers of the in
side of the earth is hardly less ap,
palling. All Investigations unite 20
prove that tie heat Increases as we de-
Sccnd deeper in the terrestrial crust
at such a rate that forty or fifty miles
down no substance with which we are
acquainted could remain unmpIted. And
yet the same science tells Us that the
core of the globe is enormously more
rigid than the hardest steel This ap-
parent contradiction is due 10 tie ire
mendous pressure inside the earth No
rock and no metal can remain there in
the state in which we see it on the sur
face. Its molecules must lose the adj
herence characteristic Of solid b.. lies
in consequence Of the heat. but still
, they are not free to flow like an or,li-
nary liquid. because OF the compression
to which they are subjected
The phenomena of earthquakes have
given wonderful information about the
internal state of the globe All OBJ
servations show that the shocks OF
earthquakes are confined to a thin up
per shell. They originate at depth
of only few miles at the most. But
the vibrations which they set going
are felt all through the earth. often ex-
tending 10 the antip0des. The great
core. held rigid by the pressure. is ex-
trpmely elastic, aud it responds to
shock like ball of steel or Of glass.
The density of the earth increases to
ward the center. 1t is only in the up
per part OF the crust that local move
ments can take place. causing shocks
| and changes of level at the surface
Deeper down everything is gripped and
immovable. except. as already re-
marked. that the molecules Of the rocks
and metals there are subject to vibra.
ton like those OF bell against which
blow is struck
But this Is not ALL Whenever a local
release from the pressure is brought
! about by changes near the surface the
! potentially liquid but effectually solid
core at that point may suddenly be-
come fluid and gush forth through
volcanic throat or other vent But
( such effects cannot extend TO any great
depth. Nothing comes to us from the
vast interior mass. That remains a
perpetual mystery. far beyond the
searching hand of science Indirectly
4 however. we may learn much about it,
Astronomical considerations throw n
great deal OF light upon the subject
We see that through the planetary sys-
tenn rotating globes are f1attened mt the
poles. The same thing is true of the
earth. Its equator bulges: its polar
regions are drawn inward Mechan-
ical laws assure us that the cause is
to be found in the fact that the earth
and the other planets have assumed
shape under the influence of the cen
trifugal force of their rotation. That
force is necessarily greatest at the
equator. Beginning as completed mol
ten bodies. they have commenced to So
.
sumed an elliflordal form due to their
rotation.
Another very significant fact is that
the shape OF the earth corresponds with
that which a globe rotating with its
velocity would have If composed of
materials arranged to their density
that is to say, growing denser toward
hn ha lie
must be deep down in the globe: the
lighter materials have remained at the
surface. This again corresponds with
the facts of observation. We know
the total weight" and the average
density OF the earth. Ii weighs" six
seXtillions of tons. and its average
density is five and a half times that OF
water. But the substances composing
the crust of the earth have an average
density Of twice that of water. 1t
follows that the heaviest things in the
earth, on the average. exist deep with
in its exterior For all that we can
tell. its inner core may be wholly me-
tallc. At the center there is probably
an enormous aggregation OF dense me-
tallc substances.
An indication that the inner parts of
the earth consist largely if not mainly
or iron Is TO be found in the mag
netiSm of the globe. The earth is a
great permanent magnet. If we could
learn the facts 1t might turn out that
iron is the most abundant substance
in the solar system and perhaps in
the whole universe. The majority Of
the meteorites that fall upon the earth
consist of solid iron Blow the earth
to pieces and in the resulting cloud
Of fragments the rocks that we are
familiar with would be almost imper-
ceptible. There would be rain of
iron and other metals descending upon
the moon and upon any other attract
ing body in the vicinity.
This view OF the interior Of the
globe dispoSes of the notion. so pictur-
esquely developed in one of Jules
Nerne's romances. OF the existence Of
vast cavernous openings in the inte-
riOr of the earth. Such void spaces.