Evening star. [volume] (Washington, D.C.) 1854-1972, 1880-11-27
HOW LONG WILL THE SUN LAST,
Professor C. A. Young Gives his
Views OH the Future Of the Uni.
verse;
1PopIllar Science N

verse;
Popular Science Monthly.l
HOW Is the heat of the sun maintained? How
long has it lasted already? How long Will it
continue? Are there any signs Of increase or OF
diminution? After affirming that, in the pre-
sent state OF science, only somewhat vague and
unsatisfactory replies are possible. Professor
Young holds that, so far as observation goes
we can only say that the outpouring of the solar
neat, amazing as it is, appears to have gone on
history. The author thinks that there is some
truth in each OF the two theories which have
been proposed to account for the suns fire.
g. AS to the first, the impact OF meteoric matter,
IL Is quite certain that solar heat is thus pro-
duced; but the question Is whether the supply
OF meteor1c matter Is sufficient to account for
any great proportion OF the whole. After CIV
Ing Sir William Thompson's calculation OF the
amount or heat which would be produced BY
each OF the planets falling into the sun from its
present orbit, by which it appears that Jupiter
would maintain the suns present expenditure
of energy for 32, 254 years. and Mercury for six
years and 2l9 days, and that the collapse OF all
the planets upon the sun would generate suti-
$4,000 years. and after estimating that matter
equal to only about one-hundredth part of the
mass OF the earth, falling annually upon the
soaf surface ro would maintain its radiation
from astronomical reasons, that any such
quantity of matter can be supposed to reach
the sun. So large quantity OF matter would
necesstate a vastly greater quantity circulat-
ing around the sun, between 1t and the planet
Mercury. But If there were near the sun mete-
ORIG matter eQualling, for example, the mass of
the earth, 1t ought TO produce an observable
effect on the motions of Mercury, and no such
effect has yet been detected.
Astronomers, therefore, failing to find full
explanation of the cause of solar energy in
this hypothesis, have adopted q second one,
which Is, that the suns diameter Is slowly con-
tract1ng. and that the gaseous mass is grad
ually liquefying and becoming solid. The con-
| there must come time when there will be no
solar heat as there has also been time when
IL began. HOW far forward is the end, how far
backward the beginning? NeWcOmb Is author
lty for the statement that, with its present
radiation, the sun will shrink to half its present
diameter IN about five million years. Reduced
to this size, and eight times as dense as now it
would cease to be mainly gaseous and its tenn.
| perature would begin to fail. Hence, NeWconb
assigns as the term during which the sun can
supply neat enough to support life on the earth,
| as we know life, period OF ten million years.
Ihe writer somewhat more confidently casts
| his eye backward, and concludes that the sun
| cannon nave been emitting heat at the present
rate 1or more than eighteen million years ii its
neat has been generated In the manner de
ameter even many times larger than that of
Neptune's orbit to its present dimensions, as ia
| PROBABLY true IN the main, 1--WE are ineXOraOly
| shut up to the conclusion that the total life OF
the solar system, from its birth to its death. is
| included In some such space Of time as thirty
millions OF years; no reasonable allowance for
| the fall OF meteoric NATTER &C., 'could raise it
to sixty millions" The possibility OF COLL
| sion with wandering stars, and the suggestion
| OF ways as yet unconceived of for restoring
| wasted energy, are followed by the statement
| that 1.-THE present order OF things appears to be
| limited In either direction by terminal catas-
trophies which are yelled in clouds as yet i'm
| penetrable. y