Saint Mary's beacon. [volume] (Leonard Town, Md.) 1867-1983, 1878-08-15
Origin or Heat Wares.


Now that the torrid season Is practi-
calIy over, one of the questions natural-
Iy suggested by the terrific heat tsates
which spasmodieally fall upon us is I:
What is their origin! Are they due to
local influences; or directly caused By
fluctuations in the sun itselfi Docs that
great source Of light and heat remain
uniform In its supplies, or are its forces
subject 10 periodic ebb and flow In
shGrt, is the sun a variable star? ? Start
ling as an affirmative answer TO this
last question might appear, there would
really be nothing strange in such fact.
The fixed stars are known to be gigan-
tic suns, shining by their own light, and
giving out, undoubtedly, enormous
quantities of heat, although we are too
distant to perceive il, and each Is PRO-
baby the centre of an attendant system
of planets, just as our sun rises. Yet
among these far -6if worlds we find many
subject to periodic variations OF brilIian-
CIV, appearing and disappearing with al
most clockwork regularity, or suddenly
flashing up as new stars and rs quickly
fading away forever.
One of the most striking examples Of
this variability is the star Mira, or ''the
wonderful" in the constellation Of The
Whale. This singular body passes ev-
cry year through succession of changes
so extreme that for FIVE months it is abb
solutely invisible, although, when at ITS
brightest, il equals in splendor star oi
the second magnitude, Its greatest
brilIIancy, too, is not always the same.
II does not increase or diminish by the
same graduations, nor are the success
sive intervals of its variations constant.
In fact, while the average period Of Its
changes Is about 331 days. the star is
also subject to many minor irregulari-
ties. =
Another variable sun Of short period is
Algol in Persens. At its brightest, this
star is commonly Of the second magni-
tude, but in less than four hours Il falls
to one Of the fourth magnitude, and re-
mains in that condition for twenty min
utes. Then it begins to increase in
brightness, and in three hours and
half more has regalned its rank Is Sec
ond magnitude star, and cUntinues to
hold ii for two days and half, when it
again passes through its periodic changes.
These are By no means isolated cases.
The number of stars known TO be vari-
able is large; some ofthem pass through
their round of variations in long and
others in short periods, and all are ap-
parently liable to fluctuations which
conform TO no fixed rules.
Several facts, says the New York 1Fi-
bune from which we quote, seem to in
dicate that our sun is a variable star of
the same kind, though not subject to
such extreme changes as Mira and Al
gol. II is frightful to think what would
happen If it disappeared altogether for
Iour years, as Mira once did, or even il
It went through such rapid variations Of
brilliancy as We see in Algol; but that
the sun does vary can hardly be- doubt
ed. In some years its surface is found
to be almost perfectly az rest In 9TH
ers, its forces seem TO be in an eztraor-
dinary state Of activity, giving rise to
enormous spots which undergo the most
rapid and violent changes, and throw
ing out vast masses of incandescent
gases to inconceivable distances. How
these changes are produced still re-
mains a mystery. On the suppositioE
that the suns heat was kept Up by q
constant stream OF meteors falling into
that body, it was natural 20 suppose that
the variations in the amount Of heat
thrown off depended upon Irregularities
in the supply of its ineteUric fuel. On
the more generally accepted theory,
however, that the temperature OF the
sun is sustained, not by enormous show
ers Of meteors, but by the contraction
Of its own mass, these variations OF heat
and light are probably due to cores
pondfng variations in the process Of con-
densation. Judging from the outbreak
and Disappearance of solar spots, it
seems probable that the sun goes
through these changes, on an average,
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 re-
wolves around the sun in nearly the
same teFiod, some ASTRONOMERS have
sought 60 shcH that the greater Of the
solar variations were due to the seton
Of that planet, while others have sfgued
that the minor changes wete eatised BY
the earth and Venus. These views,
however, seem 10 rest On no solid feun'
dalton.
But whatever be the cause. il may be
safely assutned from the periodic pre-
valence and disappearatice ofthe spots
and IRON other Indications, that the sun,
like so many Of the stars, is really we
riabIe, passing through its phases IN a
period Of about eleven years. and that
10 It's vafisticns, and not to local infiu-
ences. must be ascribed those extrsor-
dinaTy oagb0fsts Of heat which make