The Indianapolis times. [volume] (Indianapolis [Ind.]) 1922-1965, 1931-03-25
6oIOr Sequence
ME giant-dwarf theor

covery made from observation Of
the heavens. This discovery was
that the stars could be arranged
in definite series on the basis of
size and color.
1t was found that the largest
stars in the heavens were red in
color. Slightly smaller stars were
orange. Stars just a little smaller
than the orange ones we're yellow.
Next came white stars and then
blue or blue-white ones. But these
blue-white stars apparently were at
turning point. For observation
showed that as the stars got still
smaller, the color sequences re
versed itself, going back through
white, yellow and orange to red.
Russell called the big stars giants
and the small ones dwarfs and on
this basis developed his famous
giant dwarf theory.
1t is a well-established fact that
the color of a star is an index of its
surface temperature. A red star
has a red-hot surface; a white star
has a white-hot surface.
The range Of temperature is from
1900 degrees Centigrade for a red
star. to 10000 degrees for a blue
white one.
Russell's original theory held that
a star started in life as a red giant.
Contraction, due to gravity, caused
the star to become hotter and so its
color changed, going from red to
orange, to yellow, to white, to blue
white.
But at this point it was thought
that the center of the star became
liquid due to the increase in pres
sure. Consequently, it was believed
that further contraction caused the
star to grow cooler and so it slipped
back along the color scale from
blue-white to red.
But now, in its old age, the star
was red dwarf.
Eddington'S Work
1T was largely the work of Sir
l. Arthur S. Eddington, famous
British astronomer, that led to the
revision of the Russell giant-dwarf
theory.
Eddington showed that In all
probability all stars from the red
giant to the red dwarf were gaseous
masses.
He discounted the idea that star
could have a liquid interior, al
though there are some astronomers
today who still incline toward that
view.
From Eddington's work, it also
became necessary to seek for sources
Of energy in the star other than
contraction.
Another difficulty came from the
fact that on the basis of the theory
that the galaxy evolved from
parent nebula, it is not possible to
imagine any very great differences
between the ages of different stars.
Differences must be explained on
the basis Of the rate of evolution
rather than on the basis Of varying
ages.
Still another difficulty was in
troduced by the discovery of white
dwarfs. Stars of this type which are
known to us are few in number,
but they are most interesting.
One is the companion Of Sirius,
the dog-star. Calculations indicate
that this white dwarf is composed
of gaseous material so dense that a
cubic inch Of it would weigh many
tons.
That such dense stuff should be
in a gaseous state can be explained
only on assuming that it consists
Of stripped atoms" that is the
nuclei of atoms from which the
outer electrons have been torn of.
With these facts in mind, astronz
omers have worked out new theories
Of evolution. These postilate vary
ing rates of change depending upon
the massiveness of the star, the
number of atoms within it capable
Of conversion into radiation, and
other factors.