Wood County reporter. [volume] (Grand Rapids [i.e. Wisconsin Rapids], Wis.) 1857-1923, 1872-09-05
The Comet Question.


the announcement that comet was ON
its way toward our system, and would en-.
counter the earth full tilt ON the 18TH of
the coming August The statement came
from sober Switzerland, ii was reported
to have been made upon the authority of
an astronomer of high repulc; there WAS
in it some slight internal evidence OF cir.
cumStautislity--enuu to commend il TO
those not deeply versed in the astrunomlc
lore, and SO, with that faith in astrununi.
CT predictions Which the general accu-
racy of such forecasts has inspired, the
public, or u very large section of il, nc.
cepted the warning as reliable IN SO far rs
the actual encounter was concerned, and
set itself wondering what might he the
possible consequences Ct the threatened
collision According to their lights folks
were treasured or doubted, or We're alarm
ed, or were indifferent Those who had
learnt to regard comets as airy nOthiurs
treated the report with contempt; those
who retained the ancient and classical
dread OF a bearded star were disprted,
ana in some eases addressed themselves
10 astronomical authorities in the hope of
receiving information Gf cRtha3rG to allay
their fears They were not disappointed;
INC htlLlplliltS were ullhtit " tbDlEAlltl
the alarming report on NIL its essential
points, and to offer feasible suggestion
rs to the harmless circumstances out of
which, by enormous eNaggerauon. it had
been couCocted The reasonable eN.
PLANTATION was that the Cauard had
been generated from the facts that
the earth encounters meteor
stream on or about the date referred TO,
and that meteors are in some manner al.
lied to comets, perhaps very intimately,
llAsmuch AS certain meteor streams have
been discovered to occupy and course
around the orbits of certain comets and
il has even been surmiSed that what is
solid in Il comet is merely swarm Of
mcteOrlc particles. In the actual case in
question, il is known that n comet which
itself passed in sight of us, in the year
1862, had its path strewed with metcorlc
particles, as with debris that it has left
behind it. The earth intcrsects this path
every nth Of August, and some of these
particles then plunge into our atmos.
pherc, and are kindlcd into visibility,
giving rise to the luminous metcOrs of
that date, which have long been known
in tradition-loving Ireland as st Law
renCes fiery tears. So that, on that crit
ical date, We do encounter the trail mot
the tail, for comets do nos trail their
tails) of Comet--with what harmless
consequences we all know; and it Is con
ceivable that the report to which we
have alluded grew out of some simple
announcement of this circumstance. II
may be suspected that, since each year
we cross the comets path, we may one
day fall foul Of the body itself SO we
may, bu it will not he this year, nor in
the lifetime of any one who now reads
these remarks. for the last approach was
in the year 1862 and since the comets
period of revolution round its vast orbit
is one hundred and thirteen years, it
Will not come near US again until the
year 1915, and the odds against the prob
ability Of an encounter even then are
enormous
We have, therefore, little to fear from
that comet, though we do actually run
across the path il trayerscs But kepIcr
declared that space was rs full of comets
AS the sea is Of fishes; aud, considering
the intnity of space, his metaphor may
not be so far overdrawn as, apart from
this consideration, we might be disposed
to regard ii Arago, indeed, indurscd the
kCPerian assertion SO far as to estimate
that the number of C0metary bodies which
in their orbital journeys pass through tine
solar system amounts TO over 1000, 600
Clearly this plentitude must induce some
risk Of an carth-and comet collision, for
We know Of no provision of nature for
warding off such an encounter though
we may suppose provisions TO exist for
rendering ii lnnOCuOus, if by any chance
ii should occur But the chances of &c
CurrCnCc are feeble indeed. The illustri-
Gus French astronomer whose name we
have Just mentioned calculated the prOba.
bililies Of an encounter for a Hypothetical
comet a quarter the diameter Of the earth
in size, and supposed to approach the sun
within the earth orbit; and he found
that the odds against the meeting were
2Sl 600, 600 to l. The assumed small di-
ametcr of the comet referred, of course,
to the nucleus, or supposed solid part the
nebulous surrounding which commonly
streams of TO form the customary tails
might have vastly greater size, and
the probabilities of encountcrug it
would be couespondngly increased
But we may dismiss at once any APP
prehcnsion of danger from a switch Of a
comets candal appendage. for there is
little doubt that we have repeated
~ received this, the lates: instance
having occurred but a few years ago.
The great comet OF 1861 s fully believed
to have dragged his tail over us on sun
day, the Both Of June, in that year, when
we were only twu-thlrds the tails length
from the nucleus This fact was first de.
duCed By calculation, and it has received
curious confirmation from observations
that have subsequently come 10 hand; for
an Australian observer viewing the comet
at time corresponding to our afternoon
(when it was night with HIM, saw the
branches or side boundaries of the tail
widen out and on the same evening, a
few hours later, two English observers
saw the cIOsngup or narrowing Of the
tail cone these effects being those which
considerations Of perspective would lead
us to refer 10 an approach to u and re
CGdcnCe from US. II is reasonable to con
Guide that the whole earth actually passed
through, and was for "A time enveloped by,
the tail at about sunset on the dry in
question. We are not aware that any
consequences injurious 10 man or ap-
probable by him followed from the en-.
counter We had not even trace Of any.
thing similar 10 the dry fpgs OF 1883 and
ls1l which were at one time regarded as
due TO COmetaTv cXhalatluns gathered
in some such conflict as that here alluded
TO.
Arago was not the only astronomer Who
had the curiosity 10 compute the proba-
bilitics or imprubabilitic9 Of cOme'ary
collision. Others made a somewhat sim.
liar calculation, taking for granted that
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