The Dawson news. (Dawson, Ga.) 1889-current, 1921-06-07
COMET is DUE HERE
ABOUT JUNE 18TH
EARTH MAY PASS THROUGH
ITS TAIL. IF 1T HAS ONE. MAY
BE METEOR SHOWER.
BY DIR. C. S. Brainin.

!
About the 10Th of this month the
earth is threatened with collision.
A comet known to astronomers for
about 100 years is the other party, and
its name is the Winnecke 1850 lid or
Pons- Winnecke comet.
1t so happens that on or about the
above date the earth and the comet
are going to be very close to each
other in space, if not in actual, contact.
1t is little too early, at the time OF
writing, to foretell more closely the
conditions, because the effect of the
earth's gravitation can not as yet be
exactly calculated, owing to our ig
norance of the physical data of the
comet. However, it seems sure that
we shall be about 100000 miles at
fleast from the head of the comet; per-
haps we shall pass through the tail, if
it has one.
Unfortunately, this comet is not
bright enough to make a grand dis
play in the heavens and will be visi-
bic in the telescope only. But the
naked eye observer will probably be
treated to a fine shower of Tneteors
when the earth crosses the path OF
the flying comet.
Comets in General.
In order that the reader may under
stand the effect of near approach or
i, collision between the earth and
comet, we may mention a few facts
about this class of celestial objects.
They are bodies which pass around
the sun in orbits of different sizes,
crossing many of the planetary orbits.
At one time it was believed that
comets were OF two kinds, those that
stay with the sun and those that come
into the solor system temporarily and
then pass on out into space to visit
other stars In the first class were
those whose orbits were known to be
within the solar system and those
which, though they went out beyond
Neptune, returned every so often, or,
as the astronomer says, periodically.
But it is now the more accepted belief
that even those which hav not been
observed on a return trip are merely
extremely long-period comets which
will visit us again some day. SO that
all comets may be looked upon as
bona fde members OF the solar sys-
! TEN.
The appearance of comet is fairly
bizarre for celestial body. The
"head" of a comet is the main body;
usually there is brighter and prob
ably denser nucleus within the head.
And very often there trails out into
space from the head long tail, some
times even many tails. The entire vol
ume of space occupied is enormous.
Comets has been known with heads
from 10000 up to more than 100000
miles in diameter, greater in volume
than the sun itself. Even the tails
may be hundreds OF thousands OF
miles in diameter; as for their length,
it can be as great as 100000000 miles.
But for all this tremendous sizes,
the amount of matter, or "mass," is
extremely small, SO small, in fact, that
even the greatest comets have made
no measurable gravitational disturb
anc in the orbit of any planet, while.
the effect of the latter upon the COM
cts is extremely powerful. A comet
has passed through Jupiter's family of
moons without producing any notice
able disturbance whatever.
Gas in Comets Tail.
The spectroscopic study of the
comets to determine the elements con-
tanned does not lead to conclusive re-
suits 1t seems to show the presence
of hydro carbon vapors and OF the ex-
tremely poisonous gas, cyanogen, IN
the tails. 1t was thought that If the
earth passed through comets tail
containing cyanogen, effects OF this
might be found in the atmosphere and
evil results follow. But the old earth
passed through a comets tail only ten
years ago and no such effect at all
could be noticed. In fact, some later
work makes it extremely doubtful if
the spectrum ascribed to cyanogen is
really produced by it. Surely one need
not fear death from poisoning as re-
suit of the visit OF Pons-Winnecke;
it is not a Borgia.
1 If the earth should ever hit fair
sized solid body terrific castrophe
would undoubtedly result, the human
race being wiped out. But physical
encounter with a comet need hardly
be feared. We pointed out above the
negligible mass of even the largest OF
these. The matter in the comet is in
two forms, gas and small pieces-of
stone and metal probably. The tails
are COllpIStCly SdoSOuo' ANNH II w
hit the nucleus of the comet we would
get only meteor shower containing
perhaps, some large bits to grace the
museums. The smaller pieces would
be buried up in the atmosphere. We
assure the reader of his personal safe
ty.
The Pons- Winnecke comet was real
lily discovered by Pons, the great
French comet hunter on July II, 1879,
OF possibly eleven years earlier. The
elements of its orbit were calculated
by Encke and found to be about five
and half years, but its period is now
more accurately known TO be about
five and three-quarters years. This is
the time it takes it to complete a
round of its orbit 1t was not seen
again till 1888, when Winnecke re-
discovered it, and he saw it again elev-
len wears later. 1t is faint comet and
has not been seen at all on its periodic
returns to the earth's neighborhood.