The sun. [volume] (New York [N.Y.]) 1833-1916, 1904-09-14
RADIUM AND SOLAR HEAT.
Latest Great Discovery Throws New
Light Upon Age OF the Earth.
From the National Rcpiew.

| From the National RcpteD.
The discovery of radio activity makes 1t
necessary to reconsider our estimates Of the
! time during which the earth can have been
| fitted for the abode Of living beings.
Consider first the sun 8 heat. We know
| that the sun Ia incandescent-that 1t Is a glow
| ing white hot body. 1t has been giving of
heat for countless ages. Now, how can this
| heat supply be kept up Why does the sun
not cool down. owing to the loss OF its prime
val heat?
The most obvious answer would be that
this does happen. but that the cooling Of so
| large a body Is too slow to be noticeable
| even in very long periods o; time. That might
| seem at first sight to be n plausible solution
| enough. But calculation con clusively proves
that it is insufficient The heat which is
stored up In white hot body would very
soon be exhausted if it gave out heat at ary-
thing like the rate that the sun does.
The same reason prevent cur supposing
that combustion can account for the output
OF solar heat.
Until lately the theory advanced by Won
Helmholtz has held the field. He showed
that II the sun was assumed TO be steadily
contracting TO smaller Dimensions. II. IN fsot
the outer parts were assumed to be falling
down on the inner ones. enough heat would be
generated In the process to account for the
observed output for a considerable period.
Is oo to Se
by the most careful observ ations on the sun q
diameter which can be made.
tons of this kind are affected by considerable
sources OF uncertainty; but when due allow
hsye fos nsss Of cam
m ndf sup Indeed Vsry hsh saihoty
by human standards. But there are strong
reasons for Regarding II as an insufficient
partly zooloR ical.
The earth's surface Ia composed. in the
oonsclidated mud. deposited &C one On on top
OF the other. These layers extend to an
enormous thickness. as we are able to see
lowest ones have been brought to the surface
by upheaval. We can form some idea Of the
iaysrs would Si take II we examine cases where
lent opinion is that fifty million years is quito
very lowest of the stratfed rocks land por-
haps even the very lowest, contain fossils.
thus II is certain that the EARTH surface was
fitted for the abode OF animal life at the time
they were deposited. In other, words, its
temperature cannot have then been widely
must have been shining then with much tho
same brilliancy that 1t docs now GO that geo
lo gical eyidenceseems to require much older
age for the suns heat than IL mas been possible
to account for.
Zoology points in the same direction. Con-
COnIleNlit Ol
OF the bodies of the higher animals. and esne-
cially OF the human body: consider further the
fact that not the slightest essential alteratonof
development of that, structure has been OBJ
served to take place during HISTORICAL periods.
and II will be admitted that no small allowance
OF time is required for the Darwnan process
Of natural selection. by which the most COM
plicated types, Of life are believed to have
been developed from the simplest
Now that the development of heat by radio
active change has been recognized II il pos
sibie to understand how the suns heat can
have continued for much longer periods
than were formerly intelligihle, for the
present output OF solar heat would be toler.
ably we'll accounted for il the sun contained
ms much radium as pitchblende does. The
radinm present at any one moment would.
il il true have only a limited life; IL Is neces-
sarv To assume the constant evolution OF
radium, or of some other radioactive ele;;
other similar minerals. a Thousand million
years heat, can without improbabiity be
thusaccounted for.
The hypothesis that radioactive processes
are at work in the sun Is not altogether with
out confirmation, though we have no direct
proof Of IT., for helium Is abundant In the
sun: and helium n, so for as we know, essen
TALLY product Of radioactive change