Evening star. [volume] (Washington, D.C.) 1854-1972, 1927-02-15
BACKGROUND OF EVENTS
BY PAUL Y. COLLINS.

| 900 miles Of the sun il grows hotter,
/ until it begins TO give OF a gas on it
sunny side, to blister. crupt and eN-
plode. sending out masses Of matter
/ toward the sun, as "A fountain n0't"-
out streams of water. These masses
| shoot a few million miles tONl!u IL"
sun. and the sun ErdvltatIOn ne!ls
/ them along, in addition 10 the prOpu.
/ sive power of the cOmetary explosions
while all the time there Is enanatinG
from the sun another kind OF power.
| propelIns the flying particles away
/ This throws the matter back. not into
| the nucleus, but past it-back 70
| make that great tail. II is not wholly
gas-that tail is made UP more or less
of solid particles Of dust.
The flying matter forms an En-
velope shaped like an umbrella. De
tween the nucleus and the sun. That
is called the comets coma Some
times several layers form within each
other and all are illurnined by the
light OF the sun. and possibly by some
kind of electric light from the nucleus
AS this expelled matter flies 10 tte
rear it is still lighted. forming ths
visible tail The repellnE force
from the sun Is the force or pressure
of sunbeams upon matter, for lgt.
is now known 10 act with a force IS
actual as that of stream Of ws1sT
thrown from hose pressure. This light
repulsion is Is or 20 times greater
than the force of gravity OF the sun
and so the matter of the tail starts
on it's own parabolic fight through
space and is never returned 10 the
nucleus. Thus the nucleus gives OF
its substance through the centuries
whenever it nears the heat OF the
sun, until at last it wears out and dis
appears. Even though that matter
whether stone or metal. is in small
units like fine dust, it obeys the laws
of motion and goes on forever upon is
set path, for it is travelling through
vacuum, where even q feather would
fly on forever around an orbit once
assigned to it.
There is a cometic answer TO Low
ellis query, What is so rare as q
day in June?" The answer is a comet
in June. or any other month. for a
comet tail and coma are SO extremely
rare" that they do not even curtain
the stars and those luminaries remain
visible through the densest part of
the coma and tail. The particles.
whatever their size. are so sparsely
scattered in the tail that almost all
the sunlight traversing it goes
through between them. 1t is as
dense" as five or six marbles scat
tered through cubic mile. Yet the
matter of the tail is affected by the
gravitational attraction of the planets
ii passes near.
LeXelrs comet in 1870 came so
near the earth-a few millions az
miles-that it had its tail bobbed by
earth's gravitation. the length equiva-
lent to the distance which light flies
in two and one-half days. Jupiter
clipped the orbit of Brooks comet i'm
1856. so it was shortened from %
years to a 7-year time table. From
that fact learned astronomers deduce
that given mass of that tail would
weigh only one ten-thousandth rs
much as the same bulk of our earth
and they confde to us that III
comet of average size nucleus 10000
miles in diameter. or 10 times the
diameter of the EARTH had a mass
equal TO q millionth Of that of the
earth its density would be 1926, 900
OF that of the air at the earth's sur.
face-a degree of rarefaction reached
only by good air pumps.
That story sounds, thin" but IL IS
vouched for by DIR. Hall of the Naval
Observatory. So what is there to
worry about If this tail, so much
thinner than air. should swipe the
earth? The bulk of all matter In
cent of what was excavated In
digging the Panama Canal. and II
extends millions of miles. Even If the
tail contains poison gas. II Is so light
that all that would touch the earth
would do no harm. Could IL even
penetrate our far denser atmosphere?
a cubic mile of comet tails weighs
only half an ounce. A whole comet
tail and coma and nucleus-weiEhs
% 100000 tons, but IL is so big and
earth is so tiny. we could not get
more than little wag. why
WOrry?"
That brings us to an atom. which
in school we We're taught was inf
nitely small and indivisible. Science
now tells us that a single atom is 81
miniature of the solar system; it has
It's nucleus. around which roll it's
planets. proportiOnaliy as far from
the nucleus as are the solar planets
from the sun. When the question
was asked of DIR. Hall. at the Naval
whether an atomic
solar system" also had its comets
nying In tiny orbits, he answered
Possibly" and perhaps his great
telescope will discover the hyperbolic
curve OF some wandering atomic
comet.
A great meteor struck the earth
near Cincinnati last week, which may
be an advance card from next Junes
comet, though science has not def.
nitely read the name-"Pons-Wi-
necke."
.r--x. 1nAw - w., W C~ii,u.t