Evening capital. (Annapolis, Md.) 1884-1910, 1892-10-03
THE EARTH MUST DIE.
An Illustration Showing That the Solar
System win Inevitably Expire.


Consider fywheel or clockwork as
driven by weight and the heat gener-
ated by friction against the motion OF
wheels and pendulum and by impacts
of teeth against the pallets ofsan escape
ment. Our knowledge of properties of
matter and Of modes OF propagation of
heat by radiation or condnction, and of
the efficiency of heat as . motor, discov-
cred by several thousand years Of OBJ
servation and several hupdred years of
experiment and dynamical theory, suf.
fees to show that when the weight is
run down and the potential energy (or
capacity to do work. which it had in the
beginning has been all spent in the heat,
this heat is not available for raising the
weight and giving the clockwork re-
newed lease Of motivity.
The solar system, according to the
best modern scientific belief, is dy-
namically analogous TO the clockwork
IN all the essentials of our consideration
Not going back in thought to begin
ming of which science knows nothing,
let us compare the solar system as ID
was 5000 years ago with the solar sys-
clockwork which three hours ago was
known to be going with its'weight par
tally run down, and which is still go
ing with its weight not yet wholly ran
down.
During these ], 900 years the sun has
been giving out radiant heat Qight be-
ing included in the designation radiant
heat in all directions, propagated at
the rate Of about nine and half million
million kilometers per year, and there
fore twenty eight and half Thousand
million million kilometers in 5000 years
We do not know whether the light which
left the sun 5000 years ago is stilltravel-
ing outward with almost undiminishea
energy or whether nearly all is already
dissipated in heat, warming the lumini-
ferrous ether or ponderable bodies which
have obstructed its course. We may,
think, feel snre that it is partly still
travelling outward as radiant heat, and
partly spent Cor dissipatedD in warming
ponderable matter (or ponderable mat
ter and the lnininiferous ether)
The running down of the weight in
the clockworlS has its perfect analogue,
as Helmholtz was, believe, in reality
the very first to point ont in the shrink.
age of the sun from century to century
under the influence of the mutual gray
itational attractions between its parts.
The heat producing efficiency of the fire
which there would be il the sun We're a
globe of gunpowder or guncotton burn
ing from its outward surface inward
that is to say, the work done by the po-
tential energy of the chemical affisiity
between uncombined oxygen and carbon
and hydrocarbons, attractive forces as
truly forces and subject to dynamic law
as is the force of gravity itself, is abso-
lutely infinitesinlal in comparison with
the work dore by the gravitational at
traction ON the shrinking mass adduced
by Helmholtz as the real Source of the
suns heat.
The whole story of energy now in the
sun, whether of actual heat correspond
ing to the SUMS high temperature or of
potential energy (as of the not run down
weight of the clockwork) potential en-
ergy of gravitation depending on the
extent of future shrinkage which the
sun is destined to experiences essen
TALLY finite, and there is much less of it
now than there was 100000 years ago
Similar considerations of action on a
vastly smaller scale are of course appli-
cable to terrestrial plutonic energy and
thoroughly dispose Of the terrestrial "per-
petual motion" by which Lyell and other
followers of Hutton, on as sound prin-
ciples as those of the humblest Inechan-
ical perpetual motjonist, tried to find
that the earth can go on forever as it is,
illuminated by the sun from infinity of
time past to infnity of time future, al
ways habitation for race after race of
plants and animals, built ON the ruins of
the habitations of preceding races Of
plants and animals
The doctrine Of the dissipation ener-
gy" forces upon us the conclusion that
within finite period of time past the
earth must have been, and within fin
ite period of time to come must again
be, unfit for the habitation of man as at
present constituted unless operations
have been and are to be performed
which are impossible under the laws
governing the known operations going
on at present in the material world
Fortnightly Review.