The San Francisco call., 1896-06-21
WHEN THE WORLD
COMES TO AN END.
It May Happen by an En-
counter With a Va
grant Comet.
There May Be Sudden Changes in
the Suns Veil, Which Would
Burn Us Up.
But the Most Likely Fate, Says Gar.
rett P. Serviss, Is That of
Freezing to Death.
Will the world ever come to an endq

Will the world ever come to an end?
If so, when will its end be and in what
manner will it be brought about? Will
the earth be destroyed by fire or by frost,
or how may it be expected to end?
Garrett p Serviss answers these ques-
tions in an interesting way IN the New
York World. He says:
We can classify the possible accidents
by which the heavens might be caused, in
scriptural phrase, to ''roll up as scroll ,
and the "earth to melt with fervent heat"
under three principal heads:
First-Encounter with comets.
Second-Sudden changes in the sun.
Third ollisions with unknown bodies
in space
AS to encounters with comets, it should
be said, in the first place, that the chance
OF such an accident occurring is exceed
ingly slight, Notwithstanding the fact that
comets come soaring into the solar system
frop- every possible direction-from above
and from below, from the east and from
the west-having the most complete inde-
pendence of those influences which govern
the direction or the motions OF the planets.
Yet as a matter of fact, the earth has
actually encountered at least tTo comets,
although in neither case wa3 the meeting
a direct collision involving the entire mass
of the comet.
One OF these encounters took place in
1861, when great comet swished its tail
across the earth and the moon and there
by created a brief luminosity of the
atmosphere at night without producing
any other recognizable effect.
The other instance occurred in 1872,
when part-how large a part we do not
know-of Biela's comet met the earth at
the crossing point of their orbits, and was
burned in the upper air, producing a
splendid display of fireballs, but doing no
damage.
Another form of calculation has shown
that, on the average, an encounter between
the earth and comet cannot occur mo-
than once in 100000 years. Only we
have no means of telling when this period
of $4,000, 600 years began to run.
The next species of accident to be con-
sidered concerns what is going on in the
sun itself. We know that the sun is a
globe of matter, resembling the earth in
the nature of its materials, but existing at
stance must be in a gaseous state.
That is to say, the sun contains such
metals as iron and silver as well as such
gases as hydrogen, but, owing to the tre-
mendous heat, the iron and silver. as well
as every other substance in the sun, are
continually in the form of hot, glowing
gases. and are never cool enough to assume
the form of solid metallic masses which
they take on in the earth.
At the surface of this immense sphere of
metallic gases, which constitutes the sun,
and which is between 100000 and 900 600
miles in diameter, there is a partial cool
ing and the gases are little condensed
and tend to form vast glaring shell of
heated clouds, inclosing the blazing
nucleus of the sun within.
This cloudlike shell absorbs portion of
the radiation poured out from the interior
of the sun and the effects of that absorp-
ton are visible as black lines in the spec
trum of sunlight. A certain amount OF
the light and heat of the sun are thus cut
off and does not reach the earth and the
the other planets, as it would do but for
the absorbing shell surrounding the sun.
Thus we may say the sun wears veil
which renders its face less dazzling and its
gush of heat less intense for US than they
would be if the veil were removed.
Now, looking among the other suns of
space-the stars-we find some whose wells
of metallic vapor are thinner than our
suns and others which wear thicker wells
than that which covers the face of our god
of day.
One great star, Areturus, sun probably
hundreds and possibly thousands of times
more powerful than ours, Is fairly choked
by the density of its absorbing envelope,
or shell. Others still, like the wonderful
variable star Mira, show by their changes
that they are still further advanced
toward extinction, but that they probably
experience periodic outbursts during
which, for a short time, they blaze forth
with thousand times the fervor and in
tensity of heat and light than that they
ordinarily exhibit.
The application of all this to our present
discussion appears when we consider that
the phenomena of sunspots, which at one
time increases and at another time de-
crease in size and number, indicate that
our sun, too, is variable, and that although
lHeIe Is no human record OF any alteraUlOn
in the amount of the suns radiation suffi-
Gent to affect life on the earth, yet the
example of other stars shows that such an
alteration is possible.
To be sure, it is not likely to come about
suddenly, yet we cannot be absolutely cer-
tain on that point. There is considerable
historic evidence in favor of the view
which some astronomers have adopted
that the great star Sirius has, since the be-
ginning of the Christian era, changed in
color from red to white.
Analogy would lead us to believe that
such change must imply an alteration in
the spectrum of the stars light, such as
would be produced if the vast absorbing
veil that covers the face of Arcturus were
removed and that great sun permitted to
send forth its tremendous radiant energy
unimpeded. That thing happening to
Arcturus would, | think, result in the de-
struction of life on every planet circling
its rays.
AS to the probability of such an occur
rence-the chances for and against it-no
data exist for making calculation.
The third form of accident to which the
Il. .l-x