The Paducah evening sun., 1910-04-06
Halley's Comet and Its Itinerary
Around The Sun and Past The Earth

the two facts that its path crosses
the paths of the planets, and that
new comets. with unknown paths,
are constantly bursting upon our
vision, might well give us concern
as to the safety of our globe.
This question may be dealt with
partly on the basis Of probability.
IL was the opinion of Babinet that y
collision was likely to occur once in
15,00O,00O years: Prof. William H..
Pickering regards the core OF a
comet, from which the chief danger
would rise, as liable to strike the
earth once in 1OO,OOO.O00 years. lie
finds that, in the last half of the
nineteenth century 12l comets pene-
trated the sphere of the earth's orbit
From this he deduces that we should
expect to be struck by the core OF n
visible comet only once in about
4O0, 100000 years; but we might ex-
/ pect collision with some part OF the
larger head once in 100000 years.
lie, however, doubles this frequency
to once in 2.O0O.QOO years. owing to
the fact that thea orbits of comets
are more frequentIy distributed near
the ecliptic. the plane in which the
earth travels. He believes that, dur
ing the great star shower OF 1888,
we passed close TO the core of an
invisible comet. and possibly the
same in the year 902, the year of
stars. There is nothing in these
figures to stsrue a man who hardly
expects to survive three-seore and
ten. At their worst showing our
chances of collision are one in every
2 .OOO.O 200 years.
Yet, in Popular Astronomy for
June. 1909, Professor Pickering
points out what he believes Is direct
evidence of a oometary collision.
This is found in what is known as
Coon Butte in Northern Arizona.
This, II seems. is really no butte at
all. In the midst of a plain rises
"a hill. 15O feet high. with a crater
of precipitous walls. three-quarters
of mile across. In this neighbor-
hood about a dozen tons Of the So
have been picked up. of a character
entirely different from that of the
adjacent rock. supposedly the frag-
ments of a comets head Two thou
sand of these we're found arranged
in a crescent concentric with the
crater. Under the latter are found
great deposits of silica. so finely
powdered as quite clearly to demon
strate the work of sudden impact.
Meteoric matter has been found
mixed with this 10 depth of 800
feet. Large pieces of meteoric iron
have also been found at somewhat
lesser depths.
Professor Pickering gives his at
tention also to the fact that seven
of the worlds 10 largest meteorites
have been found within 600 miles of
this point. some OF these lying with
in 100 miles OF each other. suggest
ing community OF origin. From
these and other facts he concludes
that, in Coon Butte. we have evil
dence of the earth's having been
a part of the nucelus OF comet;
this. because it happened to be NOV
ing In the same direction as that of
our globe. overlook IL with a rear
end collision" which consequently
was lacking in sufficient force to do
greater damage. This Is. perhaps.
the only positive evidence existing
that the earth. in all the ages OF its
history. was ever actually struck by
a comet.
II it happened once. 1t might hap
pen again; although, according to
French astronomers, there is no dan
ger whatever from Halley's comet,
and only one chance in 2S1.OOO. i
600 from all the rest. II cometsI
Travelled the same plane with the
earth, as the planets do so nearly.
then the probability of collision
would be greatly increased. But
comets strike in from ali conceiy-
able directions. and in planes dlverg-
ing from ours by all conceivable
angles. And, though many of them
cross the path of the earth twice in
coming and going. they do so as ele-
vated and subway trains cross the
path of a surface car. II is the aim
Of railroad builders to eliminate thel
grade-crossing. In the universe Il
is eliminated. IL is almost an in
credible thing that a comet should
strike directly into the earth's path. |
In the case OF Halley's comet, now
sweeping down upon us. and SO soon
to fill all with awe and some with
dlsmay, this body rises above the !
earth's level on January IS, 1910:
crosses our path overhead on March |
II; drops below the earth's level on
May IS and crosses beneath our
path on May %. Even If the comets
crossing our plane should take place |
where it also crosses our path, the
probabilities against the earth's
happening along at the same instant
would be practically infinite. Here
is the earth flying through space az
1000 miles a minute, and Halley's
comet dashing across our path at
1,54S miles a minute. With such
speed, we should have to meet at the