The Elk County advocate. [volume] (Ridgway, Pa.) 1868-1883, 1878-08-01
ORIGIN OF HEAT WAVES.
where ths Itot Weather Conc. tsr.u


whete the Hot Weather Comes from.
Now that the torrid season is prac.
tically over (says the New York 7'i6une)
one OF the questions naturally suggested
by the terrific heat waves which spas
medically fall upon us is /: "What is
their origin Are they due TO local infiu-
ences, or directly caused by fluctuations
in the sun itself u Does that great
source of heat and light remain uniform
in its supplies, or are its forces subject
to periodic ebb and fow2 In short, is
the sun variable star ? Startling as an
affirmative answer to the last question
might appear, there would really be
nothing strange in such q fact. The
fixed stars are known to be gigantic
suns, shining by their own light, and
giving out, undoubtedly, enormous
quantities of heat, although we are too
distant to perceive it, and each is prob
ably the centre of an attendant system
OF planets, just as Our sun is. Yet
among these far-of worlds we find many
subject to periodic variations of bril-.
liancy, appearing and disappearing with
almostcIockwork regularity, or suddenly
haring up as new stars and as quickly
fading away forever.
One of the most striking examples
OF this variability is the star MIRA,
or "the wonderful" in the constel-
lation of The Whale. This singu-
lar body passes every year through
succession of changes 80 extreme that
for five months it is absolutely invisible,
although. when at its brightest, it equals
IN splendor q star of the second magni-
l Ttu cd -
always the same. 1t does not increase or
diminish by the same graduation, nor
are the successive intervals of its varia-
tions constant. In fact while the aver
age period of its changes is about 331
days, the star is also subject to many
minor Irregularities. Another variable
sun OF slort period is Algol in Perseus.
At It's brightest this star is commonly of
the second magnitude, but in less than
four hours it falls to one of the fourth
magnitude, and remains in that con-
| dition for twenty minutes. Then it be-
gins to increase in brightness, and in
three hoursand half more has regained
its rank as asecond magnitude star, and
continues to hold it for two days and
a hall, when it again passes through it's
periodic changes. These are by no
means isolated cases. The number of
stars known to be variable is large
some of them pass through their round
of variations in long and others in short
periods, and all are apparently liable to
| fluctuations which conform to no fixed
rules, ~~tA---------
Several facts seem to indicate that our
sun Is variable star of the same kind,
though not subject to such extreme
changes as Mira and Algol. 1t is fright
full to think what would happen if it dis
| appeared altogether for four years, as
Mira once did, or even if it went through
such rapid variations of brilliancy as we
see in Algol but that sun does vary can
hardly be doubted. In some years its
surface is found to be almost perfectly
at rest In Others, its forces seem to be
| in an extraordinary state of activity,
giving rise to enormous spots which
undergo the most rapid and violent
changes, and throwing out vast masses
of incandescent gases to inconceivable
| distances. How these changes are pro-
duced still remains mystery. On the
supposition that the suns heat was kept
up by constant stream of meteors fall
ing into that body, it was natural to
| suppose that the variations in the
amount of heat thrown off depended
upon irregularitiset in the. supply hefaits
accepted theory, however, that the tenn
perature OF the sun is sustained, not by
enormous showers of meteors, but by
the contraction of its own mass, these
variations of heat and light are probably
due to corresponding variations in the
process of condensation. Judging from
the outbreak and disappearance of solar
spots, it seems probable that the sun
goes through these changes, on an aver
age, every eleven years, though the time
may extend to thirteen years, or be less
than ten. Taking this period of eleven
years, and remembering that Jupiter
revolves around the sun in nearly the
same period, some astronomers have
sought to show that the greater of the
solar variations were due to the action
of that planet, while others have argu d
that the minor changes were caused by
the earth and Venus. These views,
however, seem to rest Oh no solid foun-
dation.
But, whatever be the cause, it may be
safely assumed from the periodic preva.
lence and disappearance of the spots
auu iIola otutT luulChtlOue, Uilab tQ6 SUD
like 80 many of the stars, is really
variable, passing through its phases in
aperiod of about eleven years, and that to
its variations, and not to local influences,
must be ascribed those extraordinary
outbursts of heat which make life intoi-
cradle in summer and are doubtless
the origin of our exceptionally mild
winters. 1t seems probable, too, that
our heated terms are likely to be much |
more severe in the years OF n-spot |
abundance, than in those when solar
disturbances are few, though on this
point there is no conclusive evidence.
The fearful heat of 1872, however, oc-
Cured near the sun-spot maximum,
while the milder infections both of this |
simmer and of 1876 happened near the |
sun-spot minimum. Future .observa.
tions will no doubt throw much light on |
these obscure points, and it may even
be that as our knowledge of solar phy-
sizes increases we shall be able to predict |
the arrival of these unusual heat waves,
and thus rob them of half their terrors. |
A Short Starv of Paris Iifa