The New York herald., 1922-10-29


Observatory.
BY DONALD H. MENZEL, M. A..
Graduate College, Princeton.
A STRONONiY is the most ancient
~ Of all the sciences. AS far back
as the archeologist is able to
find records Of primitive man we are
able to trace its influence. Ancient
temples are placed so that the sun or
some certain constellation will light
them at different times of the year.
1t is said that the Egyptians built one
OF the pyramids SO that the Pleiades
could be seen through it's main pas
sage. Throughout history we find the
rich and varied traditions Of astronomy
playing an important part in the de-
velopment of civilization. In the Dark
Ages the pSeudo-science. astrology,
hourished and served its purpose.
While 1t was based on the erroneous
supposition that the affairs Of men
could be foretold from the stars, It
finally led scientists to investigate the
myriad hosts Of heaven in the hope
Of finding their relation to humanity.
1t was not until 1910, however, that
the means of doing this was given us.
In that year Calico made the first
celestial telescope and we began our
study Of the heavens to find the place
Of the earth in the universe. That
event alone ushered in the modern
era and left the superstition 81 the
medieval ages far in the rear; but for.
many years our progress was slow.
The telescope was q help. but We had
to learn how, to use it to the greatest
advantage.
Finally we learned that the planets
were more or less solid masses, cool.
and revolving about the sun. from
which they reflected the light that
rendered them visible. 1t was not
difficult matter to find their distances.
Stars Far More Distant
And Shine by Own Light
Astronomers soon came to recognize
the differences between planets and
stars. The latter are at a much greater
distance and shine by their own light.
In fact, they are suns. some Of them
giants in size and shining because they
are hot balls of glowing gas. Their
distances were unknown. and all at
tempts to measure them were unsuc-
cessful until Bessell, in 1888, succeeded
In determining the distance Of 81
Eygni, small star just visible to
the naked eye.
The only method that astronomers
gould use for finding the "parallax,"
which is the astronomical name for
distance, was the application of the
well known fact that near object
viewed from two different positions
will appear to have moved with refer
ence to objects further away. The
tirst estimate Of stellar distances came
from measuring the amount Of this
shift Of the near star among the fur
ther faint ones.
As this method could be applied only
10 the fcw nearest stars. research on
this line was at a standstill again un-
III recently. Within the past decade a
new era Of astronomy has risen. Aim
less star gazing was cast aside and
theoretical work was done which had
COR a foundation the we'll known laws
Of physics and chemistry bound to-
gether with the chains of mathematics.
These theories. which were verified by
experiment and research, established a
fundamental basis for the recent ad-
vancee.
One Of the questions for which an
mswer was sought and found was, how
are the stars formed? With the help
Of mathematics DR.. Henry Norris Rus
sell, now professor OF astronomy at
Princeton University, was able to cal
rulate just what the process was. 1t
was found that any large mass Of mat
ter in space would gradually collect to-
gethcr and contract by the forces Of
gravitation. M
Interior Pressure Causes
Intense Light and Heat
As the gaseous mass grows smaller
and smaller the pressure In the center
keeps increasing. and as a result the
star heats itself to incandescence. At
first glowing family red, as It's evolu
ton progresses, II becomes orange.
yellow and then dazzling white. In
this latter state the temperature Of the
stars surface is about twice that of
tho sun. while it emits perhaps as
much as 10000 times the quantity of
tight.
The giant star has now become much
smaller and the original material is
so condensed that we find the next
stage in it's history is cooling. The
dwarf star. so called in contrast to the
giant Il once was. now reverses the
original process and becomes yellow.
orange and red In turn as it's tempera-
ture decreases.
The final state of star Is, of course,
hlackness. We find that the sun is
well advanced In the dwarf. stage and
that, unless new. forces come into play.
the end Of the next twenty million
years will see its extinction.
Hussell's work has put a powerful
nstrument Of research into the keep