Bristol news. [volume] (Bristol, Va. & Tenn.) 1867-189?, 1880-12-21
SCIENTIFIC.
How Long Will the Sun Last
PROF. c. A. YOUNG GIVES HIS VIEWS on
TIE FUTURE OF TIE UNIVERSE.
Popular Science Monthly.

How is the heat of the sun maintain
ed? How long has it lasted already P
How long will il continue? Are there
any signs of increase or of diminution?
After affirming that, In the present state
of science, only somewhat vague and
unsatisfactory replies are possible. Prof.
Young holds that, SO FAR as observation
goes, we can only say that the outpour-
ing of the solar heat, amazing rs II, ap-
pears to have gone on unchanged is
through all the centuries of human his
tory. The author thinks that there is
some truth in each Of the two theories
which have been proposed to account
for The suns fire.
As to the first, the impact Of meteoric
matter, 1t is quite certain that solar heat
IL thus Produced; but the question Is
whether the supply Of meteoric matter
Is sufficient TO account for any great pro
norton Of the whole. After giving Sir
william Thompson's calculation OF the
amount of heat which would be produced
by each Of the planets falling into the
sun from It's present orbit, by which 1t
appears that Jupiter would maintain the
SUMS present expenditure Of energy for
80, ,2ji years, and Mercury for SIX years
and 2l5 days, and that the collapse OF
all the planets upon the sun would gem
crate sufficient heat to maintain IFS sup
ply for nearly 4G,OW years, and after es-
iitnating that matter equal to only about
one-hundredth part Of the mass of the
earth, falling annually upon the solar
surface. would maintain It's radiation III
definitely. Prof. Young thinks II i'm
pr0bablc. from astronomical reasons,
that any such quantity Of matter can be
supposed 10 reach tile sun. No large q
quantity Of matter would neCessiiate q
vastly greater quantity circulating
around Tic sun, between IL and the plan
ct Mercury. But If there were near Tue
sun mcicsric matter eqnalling, for eX-
ample. the mass Of tic earth, II ought TO
produce an observable effect on the mo-
lions of Mercury, and no such effect has
vet been detected. ,
Astronomers, therefore falling 10 End
\ full explanation ~ the cause Of solar
energy in this bypothcsis, have adopted
A SECOND one, which ", That the suns
diameter ~ slowly contracting, ana that
the gaseous mass ~ gradually llquciying
and becoming solid. The conclusion Is
drawn that, if this theory DC correct;
there must come . lime when there VIII
he no solar heat, as there has also Deen 2
time when it began. How iar forward
/, the end. how far backward the begin
mnyY NcwcOmb IL authority for the
.taiement that with its present radiation,
tho aun will shrink to half its present
diameter In about five million years.
Reduced TO this sizG, and eight times "a
dcnsc as now, II wOuld cease to be main
lv gascons, and ia temperature would
Legin 10 fall. Hence, NewcOmb assigns
os ihe term during which the SIN can
s1nnlv heat enough 10 support life on
the earth. ~ wc know life, period Of
ten million years. ..e,..,
The writer somewhat more confident
Iy casts his eye backward, nDd concludes
iIot the sun cannot have been emitting
heat M the present rate for more tlian
cio ohteen million years lfiis heat had een
Granted lu the manner described. II the
sun has contracted from diameter even
many times larger Than that of Nep.
| uune's orbit 10 its present dimensions,
No "a probably true In the main. 1--WE nip
inexdrably shut up to the conclusion that
,he total life of The solar system, from
he birth TO its death, IL included 10 some
such spacc of time ~ thirty millions oI
vears, no reasonable allowance for The
fnll of meteorlc matter" &C., could
raise II TO sixty millions" The posHl'
blllty of collision with wandering stars
mud suggestion Of ways as yet uncon'
celyed OF for restoring wasted energy
are followed by the statement that "th'
nreeent order Of things appears TO b'
limited IN either direction by the terml
mi catastrophes which are yelled u
clouds as yet impenetrable'"