Pittsburg dispatch. [volume] (Pittsburg [Pa.]) 1880-1923, 1892-05-01
WHY THE Sun SHINES.
Professor Young Explains the Source
of All Earthly Life
THE DIFFERENT KINDS OF RAYS
How Sun Light Differs From That Given BY
the Carbon Filament.
THE GREAT ORB Is TOO HOT TO BuRN
THE DIFFERENT KINDS OF RAYS
THE GREAT ORB Is TOO HOT TO BURN
WRITTEN FOR THE p1sPATcH.I

artificial light. Hence has arisen ratner
common idea that there is something mys-'
terious about it, that sunshine cannot De
explained in the same way as the light OF
fame, for instance.
The sun shines simply because it Is hot
tremendously so. The sun does not shine
as frefies and glow worms do; they give
light only, without much heat, emitting
only rays that affect the eye. The sun
sheds off ravs of all kinds-not only such
as are visible, but others which are equally
invisible but bring an immense amount OF
warmth to the earth. The visible rays OF
the sun-its light. in the strict sense OF the
word light-form but small fraction Of its
whole radiation. Now only very hot bodies
act in this way. ''Phosphorescent" bodies,
which emit visible rays alone without
others in their company, may be cool
while they shine; not so those which send
out all kinds of rays together.
Power shown by rhe Glass.
That the sun is really most intensely hot
is directly shown by means of a burning
glass. Many years ago great lens Of This
sort, nearly four feet across. was made in
England as a present to the Emperor OF China
Before il was sent off some experiments
were made with it. and the results were
very interesting and instructive. When
properly set up in bright sunshine and adj
iusted, it gathered all the rays that fell
upon its broad surface into a small bright
spot called the 'tfocus" (the word means
fire place") and there the concentrated
rays were so intense that nothing could be
found to withstand it. The focus was hot
49, Lo dapoa kuav how
to make, so that even lime and platinum
melted in it like wax.
Now the point is that such a focus can
never be quite so hot as the surface Of the
sun itself. In this case it was only about
as hot as it would be at a distance from the
sun equal to the moons distance from the
earth. There is no question that the suns
surface is intensely hot; and if SO it must
shine of necessity.
Next comes the question, ''What makes
it hot?"
Until the days of electricity nearly all
our artificial lights came from flames in
which something was burning; is the suns
surface, then, burning flame? No, It is
too hot to burn.
The Sun Is Too Hot to Burn.
The very essence of combustion, or burn
Ing, is that two or more chemical elements
are entering into combination with each
other, producing heat in the process When
stick of wood burns the oxygen Of the
afr is seizing upon and combining with the
hydrogen and carbon that mainly compose
the wood; and the molecules OF carbon,
after their hydrogen partners have COM
bined with oxygen companions. themselves
are attracted by other oxygen molecules and
glow and shine for a while until consumed
and converted by the new union into the
so-called carbonic acid. Now this COM
bination of oxygen and carbon pro-
duces a certain fixed temperature, which
can never be exceeded by a fame
involving those materials; and if the mole
cules of oxygen and hydrogen, or of oxy-
gen and carbon, come together at q higher
temperature, j. E., in some place where it is
already hotter than they could make it by
their union, they refuse to conoine. Nay
further, if vapor or water, or carbonic aci
gas, be exposed to such a temperature, th'
composite molecules come to pieces, s.
speak-to use the technical term, the h
gen and oxygen. or the carbon and o.
are "dissociated''- combine again
as the temperature falls sufficiently.
Now the suns surface is In o.
bility hotter than the "dissociat
perature of any elements known
emit there; and this is what
saying that the substances of
''too hot to burn"
Source of Heat in tn
But there are other way
by which heat may be g
temperature raised beyc
known. A smith, by har
with proper precautions,
hot. In boring hole wi
wood and gimlet are he
car a1les are heated b
set the ca on-fre. In &C
certain machinery it is m
so that means have to be
doing damage.
Now it IS believed that
ball Of gases and vapors, kep.
shrinkage in size. There is no
that the shrinkage of such ball undo.
force of the mutual attraction of its par
ticles must heat it. 1t can be proved
mathematically-it is not mere matter of
guesswork or opinion-that if the sun is
now shrinking at such a rate that its dame
ter diminishes more than about 800 feet
year it must be growing continually hotter.
If the shrinkage is less than this it may be
cooling off slowly.
Almost all astronomers agree in suppos-
ing that at one time, ages ago, the sun was q
great whirling nebula or cloud, filling the
whole space now occupied by the solar sys-
TEN, and that the system has come into its
present condition by the slow condensation
of this primeyal cloud. The smaller globes
the planets-have solidifed and ceased to
shrink to any great extent. and SO have
cooled down completely, like the earth.
Electricity Not the Source.
But in the great central globe the process
is not finished, and is not likely to be for
millions of years to come, so that 1t still
glows with fiery heat that no furnace can
rival, and blazes with brilliance more daz-
cling than any human art can produce. For
myself do not think it necessary to look
further for an explanation of the intensity
of sunlight. But there are some who do not
feel quite satisfied and are disposed to call p
in the aid of electric action.
It is true of course, that thing can be
heated, and that to temperature beyond
any known limit, by passing through it an .
electrical current of sufficient intensity.
The carbon ilament of an electric (incan-
deseent) lamp is not burning" but is
made hot and luminous by the current
flowing through it. /
Those, therefore, who are dissatisfied with
the mechanical explanation of the solar
heat as produced by shrinkage, maintain
that the suns light is generated by intense
electric currents circulating upon its sur
face.
1t would take too long to show why this
is hardly likely, and the discussion would
not be suited to these columns; but there .
is no way known in which electric currents
of sufficient power could be made to act
over the whole surface of sphere at once,
nor any reason to suppose that it can be
done. Still, it is quite possible, and even
likely, that the exceptional brilliancy Of
small portions of the surface here and there
may be caused, in part, by some action Of
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