Virginia citizen. (Irvington, Va.) 1891-1921, 1909-11-12
THE PARKWAY STARS
Their Color Serves as an Index
to Their Age.
WHAT MAKES THEM TWINKLE?

Nstrono"tcai Eniems-Ihe trtervsn-
ton of Fragments of Disrupted
Worlds or the Effect of Air Currents.
This Is u question that has exercised
more than one gentleman OF science.
or course II is known that only the.
stars twinkle. the planets giving OUT
steady light. That Is the way WE,
tell star from q planet with the
naked eye.
But why does the star twinkle at ally
The answer To this seems to be on ac-
count or the greater distances Of the.
stars. the nearest fixed star being sew
eral thousand times farther from US
than the farthest planet. So around
this as a starting point have been built
two theories. One is that az the.
visual angle. or angle subteuded by
the star FROM the eye. Is so very small
that very small bodies In space COM
ing between the star and the eye
would give the effect OF twinkling.
Now. as regards those smnll bodies
actually being In space as hypothecat-
ed there is no doubt. for there are mil.
lions OF fragments of disrupted worlds
flying around In orbits about our sun,
The only question Is whether there are
enough to cause the eternal twiukIing
that Is observed. Science cannot say
that enough do not exist. for she can
not perceive the existence of the small
est fragments that actually could cause
this effect. even with her finest instru-
ments.
To illustrate. then. my meaning as
regards this covering OF the visual
angle. suppose you take a dime be-
tween your thumb end finger and hold
1t between your eye and the moon un-
I'll 1t just covers the moon. 1t will be
found to be quite close to the eye. Now
take quarter and hold IL SO that II
just covers the moon. lts distance is
at once seen to be about four times the
dimes from the eye. Thus 1t Is seen
that the farther outward the object IL
placed the larger the object necessary.
This IL In accord with what Is known
as the law OF inverse squares.
But now take a dime or even a min
head, and no matter how far you hold
1t from the eye 1t will easily cover the
largest star In the heavens. This In
on account OF the enormous distance OF
the star. the lines drawn from its sides
to the eye inclosing an angle so minute
that almost anything will hIl It. So
thus we see that this theory Is not i'm
possible, though perhaps somew hat i'm
proba BILE,
The other theory bases its argument
on the air currents. Air currents are
caused by light and heated air risipu
and cold and heavy air taking its place.
Now. when light goes from a heavy
TO light gas. or vice versa, IL is bent
one way or the other. So this would
certainly happen to the light from all
the heavenly bodies. The reason IL Is
not noticed In the case of the planets
or the sun Is that they send US many
more rays as compared to the stars.
Many reasons are put forward to
show the truth OF this theory. A star
wrinkles more on the horizon than Il
does In the zenith. for Its light has to
come through greater thickness of
atmosphere: also greater twinkliug is
observed In winter than In summer.
and when rapid and brilliant twinkling
Is seen IL Is very good prophecy of
rain or snow. as IL shows the upper re-
gions OF the air to be In state Of
rapid motion OF varying air currents.
hot and cold currents meeting. CON-
minGlipg and rotating probably.
This also accounts for the changes
In the brightness OF a star, for at times
part and not all OF its light is bent
away from the eye. 1t has been no.
ticed also that a stars color has some
thing to do with Its twinklIpg on ac-
count OF the different refrartivities of
the different cOlors, j white or blue
star. such rs the Dog star. wrinkles
most; next comes the yellow aud last
the red. If one cares to look for a red
star. Betelgeux is one and can be
found In one corner OF the constella.
ton Orion.
A rather interesting thing has been
ascertained In astronomy as regards
the relation between the color OF a star
and Its age. The white or blue stars
are considered young or In the prime
OF life. with many more million years
to their career. while red star. as
Betelgeux. Is on the wane and will grad.
ually go out In the next few million
years. See II IL doesn't. The yellow
stars OF course come between the blue
and the red in point OF age. Ii IL en-
couraging to. find that our own sun Is
classified as white star. - A. L.
Hodges In Cincinnati Commercial Trib-
une.