Evening journal., 1892-09-14
THE EARTH MUST DIE.
An Illustration showing That the Solar
system win Inevitably Expire.

An Illustration showing That the Solar
system W1l Inevitably Expire.
Consider hywheel or clockworlS as /
driven by weight and the heat gener-
ated by friction against the motion of |
wheels and pendulum ana by impacts
Of teeth against the pallets of an escape
mont. Our knowledge Of properties of
matter and of modes of propagation of |
heat by radiation or conduction, and of |
the efficiency Of heat as u motor, discoy-
cred by several thousand years of OBJ
servation and several hundred years of
experiment and dynamical theory. suf-
fees TO show that when the weight is
run down and the potential energy Tor
capacity to do work. which it had IN the
beginning has been all spent in tho heat,
this heat is not available for raising the
weight and giving the clockwork re-
newod lease of motivity.
The solar system, according 20 the
best modern scientific belief, is dy-
nanically analogous to the cloclswork
in all tho essentials of our consideration.
Not going back in thought TO begin
ming Of which science knows nothing,
let us compare the solar system as it
was 5000 years ago with the solar sys-
tenn as it IS now. Let our analogue be
q clockwork which throo hours ago was
known 70 be going with its weight par
TALLY run down, and which IS still go
ing with its weight nc. yet wholly ran
down.
During these 5000 years tho sun has
been giving ont radiant heat Digit be-
ing included in the designation "radiant
heat') in all directions, propagated at
the ratio Of about nine and a half million
million lilmetors per year, aud there
fore twenty eight and half thousand
million million lIilomoters IN 5000 years.
We do not know whether tho light which
left tho sun 5000 years ago is still travel
ing outward with almost undiminished
energy or whether nearly oil S. already
disapated ia heat, warming the luinini-
ferrous ether or ponderable bodies which
have INSTRUCTED its course. We may,
think, feel sure that IL IS partly still
travelling outward rs radiant heat, and
partly spent tor dissipaied) in warming
| ponderable matter Tor ponderable mat.
ter and the luniniferous ether.
The running down of tho weight in
the clockwork hns its perfect analogue.
rs Holmholtz was, believe, in reality
tho very FIRST TO point out in the shrink
ago Of the sun from century 10 century
under the influence Of tho mutual gray
itationnl attractions between It's parts.
Tho heat producing efficiency Of the fire
which there would be If tho sun were q
| globe OF gunpowder or guncotton burn
ing from It's outward surface inward
that is 10 say, the work dono by the po-
tential energy of the chemical affinity
between uncombined oxygen ana carbon
and hydrocarbons, attracti~e forces as
truly forces and subject to dynamic law
as Is tho force OF gravity itself, is ALSO
lutely inhnitesimal ia comparison with
the work done by the gravitational at
traction on tho shrinking mass ndduced
by Helmholtz as tho real source Of the
sums heat
Tho whole story Of energy now IN On,
sun, whether Of actual heat correspond
ing to the SUMS high temperature or o.
potential energy las Of the not run dow
weight Of the clockworlz)-potoniial en-
ergy Of gravitahon depending on III
extent Of future ehrinkage which th
sun Is destined TO exporienco-is oascn
TALLY fnito, and there Is much less Of /
now than there was 300 600 years ago
Similar considerations of action on
vastly smaller scale arc Of course appli
cable TO terrestrial plutoniSoncrgy, an,
thoroughly dispose Of the terrestrial 'por
petual motion" by which Lyell and othe
followers Of Hutton, on as sound prin
ciples as those Of the humblest inochan
ical perpetual motonist, tried 20 fn'
that tho earth eau 90 on forever ns it IS
Illuminated by the sun from inhnity O
time past to infnity Of time future, al
waye habitation for rnce after race o
plants and animals, built on the ruins O
tho habitations Of preceding races o
plants and animals.
The doctrine OF tho "dicsipaton cnes
gy' forces upon us tho conclusion tha
: within a finite period Of thnc past Tn
, earth must have been, and within q fin
ite period Of tifno to como must agaii
, be, unfit for the habitation of man as n
} present constituted unless operation
? have been and are 20 be perfounc'
which arc impossible under the law
governing the known operations goin.
on at present in the material world
J Fortnightly Review.
Dogs That nnthc Regularly.