Evening star., 1934-12-19
SUN M|DDLE-AGED,
| LOSING HEAT FAST
Mt. Wilson Scientist Tells OF
! Flaming Orb Surrounded
by Elderly Neighbors.
BY THOMAS r. HENRY.

The sun was pictured as middle
aged star surrounded by elderly neigh
bors by DR.. Walter S. Adams, director
of the Mount Wilson Observatory, in
the snnual Arthur lecture of the
Smithsonian Institution at the Ma
tional Museum last night.
The majority Of the stars within the
immediate neighbornood of the solar
systematic immediate neighborhood
being a vast field of space with ra-
dius of about the distance light NOV
ing at 1856 900 miles a second can
cover in IS years-are dwarfs giving
out only fraction of the light and
heat of the sun, Dr. Adams said. They
represent what the sun may be ex-
pected to look like eventually when it
has radiated away in substance for a
few billion years more.
Proxima Centauri Fading.
One of the most striking examples OF
all is the suns nearest neighbor, the
star Proxima Centauri in the South
ern Hemisphere, which is between four
and five light years distant and gives
out only about one ten-thouSandth
part of the radiation poured into space
by the parent star of the solar system.
This is the faint companion star to
Alpha Centauri, an orb of about the
size of the sun itself Proxima Cen
tauri may be special case, but the
heavens are studded with other faint
and dying stars.
The implication is, DR.. Adams said,
that in about 10000, 100000, 900 years
the sun will have radiated away about
half its present mass and until that
time there probably will be little de-
crease in the amount of light and heat
it sends to the earth. In any event,
DIR. Adams said the living earth need
not be concerned at its impending
fate from a cold and lifeless sun.
Sun Nears Red Dwarf Stage.
While the concept of stellar evolu-
ton has undergone far-reaching
changes in the past few years, DR..
Adams said, there can be little ques-
tion that the sun-a star fairly typical
Of billions in the heavens-is in the
sequence of decline and already has
passed its best days. 1t is on its way
LOW dld I1lC leu oWdI1 SUdRe. FIOU-
ably the majority of the stars through
out the Milky Way galaxy are In this
stage, DR.. Adams pointed out. They
are so small that they cannot be de-
tected outside the immediate solar
neighborhood, but there is no reason
to believe that this is in any way ex-
ceptional.
DR.. Adams located the sun as
approximately 100000, 900 600, 900 900
miles from the center of the Milky
Way galaxy in the constellation at
Saggitarius and slightly to the north
ward of the plane of the Milky Way.
The latest calculations fix the length
across the galaxy as about 100000
light years, or approximately 600 oOO,-
O00, 900, 900, 900 miles. He pictured all
the stars as rotating around this CEN
ter at varying speeds, depending upon
their distances. The speed of the sun
in this motion is about 165 miles a
minute, and it will complete a single
revolution in its gigantic orbit in ap-
proximately 265 100000 years.
Star Spacings Are Vast.
While the stars seem to dot the
heavens in great numbers-so that in
the direction of the Milky Way they
appear as a continuous band of lumi-
Mostly to the naked eye-measure-
ments Of the distances around the sun,
a fairly tropical locality, show enor-
nous distances between them. The
average distance Is about 10000 00O-
100000 miles. In these vast inter-
spaces there are to be found only ex-
tremely tenuouS gas and coSmic dust
clouds.
Because the whole Milky Way galaxy
is rotating around its center in Saggi-
tarius, DR.. Adams said, it Is possible
to calculate its total mass, which turns
out to be about 100000 900, 900 900
times that of the sun. This would
mean that if matter were distributed
evenly throughout its whole expanse
instead of being concentrated in stars
and star systems, there would be an
average of Is grains for a space 1000
times that of the earth.
Gas Lost by Contraction.
Present indications are. DR.. Adams
said, that the billions of stars do not
represent all sizes and intensities, but,
like electric light bulbs, fall into def
mite candle power classifications, from
the enormous supergiants to the tiny
dwarfs. The law of growth in the
stellar system apparently reverses the
organic law. A star is born a giant
and ages into a dwarf. It comes into
being an enormous, extremely tenuous
mass of gas, which heats as it con-
tracts and then begins to lose its heat
through radiation, passing at some
stage in its history through approx
mately the present state of the sun.
DR.. Adams described the method
being used at the Mount Wilson OBJ
servatory to determine the distances of
great numbers of stars too far away to
be surveyed" by the Photographic
paralax method, which gives the most
reliable measurements. BY variations
in spectra, which depends upon the
state of the star itself, it is possible to
arrive at an equation which gives a
very fair approximation of distance.