Evening capital. (Annapolis, Md.) 1884-1910, 1892-05-14
THE sun WILL CEASE.
A TIME MUST CONE WHEN HEAT
FROM THE SUN MUST CEASE.

Measuring Mans Days TO Come-The
Great Orb Of Light and Life May Last
100000 Years. but Not 10000. 900.
The Secret of the Suns Heat.
Il seems to be worth while to collect
together what may be said on the sub
ject of the duration of life on the globe
1t is a noteworthy fact that the posi-
bility of the continued existence of the
human race depends fundamentally
upon the question of heat If heat, or
what is equivalent to heat, does not
last, then man cannot last, either. There
is no shirking this plain truism
OF course it is obvious that the avail
able heat generally comes from the sun
So far as the coal goes, we have already
observed that as it is limited To quantity
it can afford no perennial supply
Doubtless there is in the earth some
quantity of other materials capable of
oxidation or Of undergoing other chemi-
cal change, in the course of which and
as an incident of such change heat is
evolved. The amount of heat that can
possibly arise from such sources is
strictly limited. There is in the entire
earth Just certain number of units of
heat possible from such combinations,
but after the combination has been eff.
fected there cannot be any more heat
from this source.
Then as to the internal heat of the
earth due to the incandescent state of
its interior. Here there is no doubt a
large store of energy, but still it is of
limited quantity, and it is also on the
wane. This heat is occasionally copious-
ly liberated by volcanoes, but ordinarily
the transit of heat from the interior to
the surface and its discharge from
thence by radiation is slow process
It is, however, sufficient for our present
purpose to observe that slow though the
escape may be, 1t is necessarily going
on. There is only definite number Of
units of heat contained in the interior of
the earth at this moment, and as they
are gradually diminishing, and as there
is no source from whence the loss can
be replenished, there is here no supply
of warmth that can be relied on perma-
nently.
1t goes without saying that the well
fare OF the human race is necessarily
connected with the continuance of the
suns beneficent action If the sun ever
ceases to shine, then must it be certain
that there is term beyond which hu-
man existence, or indeed organic ex-
istence of any type whatever, cannot
anv longer endure on earth
But we have grounds for knowing as
a certainty that the sun cannot escape
from the destiny that sooner or later
overtakes the spendthrift. In his inter
esting studies of this subject Professor
Langley gives a striking illustration of
the rate at which the solar heat is being
squandered at this moment. He remarks
that the great coal fields of Pennsylvania
contain enough of the precious mineral
to supply the wants of the United States
for 200 years. If all that tremendous
accumulation of fuel were to be extract.
ed and burned in one vast confagration
the total quantity of heat that would be
produced would no doubt be stupendous,
and yet, says this authority who has
taught us so much about the sun, all the
heat developed by that terrific coal fire
would not be equal TO that which the
sun pours forth in the thousandth part
Of each single second
When we reflect that this expenditure
of heat has been going on not alone for
the centuries during which the earth
has been the abode Of man, but also for
those periods which we cannot estimate
except by saying that they are doubtless
millions of years during which there
has been life on the globe, then indeed
we begin to comprehend how vast must
have been the capital OF heat with which
the sun started on its career.
And yet we feel certain that the inces
SAINT radiation from the sun must be
producing profound effect ON its stores
Of energy. The only way of reconciling
this with the total absence of evidence
of the expected changes is to be found
in the supposition that such is the
mighty mass Of the sun, such the pro-
digious supply Of heat, or what is equiv
alent to heat that it contains, that the
grand transformation through which it
Is passing proceeds at rate SO slow that
0uK1uk lie ages HGIcScA0AC w 0U& 0DoCA-
vations the results achieved have been
imperceptible. But the energy OF the
system is as surely declining as the en-
ergy Of the clock declines as the weight
runs down.
1t seems that the sun has already dis
sipated about four-ffths Of the energy
with which it may have originally been
endowed At all events, it seems that.
radiating energy at its present rate, the
sun may hold out for 4,O00, 900 years, or
for 1000, 900 years, but not for 10000
900 years. Here. then, we discern In
the remote future limit to the dura-
ton of life on this globe. We have seen
that it does not seem possible for any
other source Of heat TO be available for
replenishing the waning stores Of the
Iuminary. 1t may be that the heat was
originally impaired TO the sun as the
result Of some great collision between
two bodies which were both dark before