Daily globe., 1883-05-24
Il DEADLF COMET.

S"" IRGt d1G3 Barn AL LiJe OF
Earth.
The idea that the comet OF 1880 may
be identical, not only with that o* 1t.t
but with that OF 1863, the period Luvi..s
been reduced from 175 years to thirty
seven, was suggested at the Astrcnom.-
cal Society in April, 1880, by Mr.. Mmsh.
mathematician of great skill, and well
known for the zeal with which lie n;-
tacks problems relating to the .4ave-
ments of the satellites of Saturn an!
Mars. He says:
"Supposing the comet of 1873 is the
same as that of 1868, it would not he
very wonderful that it should reappte.
after thirty-se7en years, instead Of l75
years. The velocity OF q body mov!nE
IN the solar system depends simply Oh
its distance from the sun, and on the
period of revolution. If the velocity Is
reduced by resisting medium, There
will be a reduction of the period, and
there is nothing whatever unreasonable
in the supposition that, however weak
the corona may be, its resistance would
have very great effect upon the NO
ton of the comet which rushes throu:h
it; SO that I should not be at all sur
prised if it should turn out that tI>
comet Of 1880 is the same as the comet
Of 1913 and that of 1868, and that is
revolution has been so much afec;,.J
that possibly it may return in, say,
seventeen years"
Now, if this theory of the comet c;
1880 be the true one, we are somewhat
more nearly interested in the m&t5er
than we are in most theories respac';u<
comets. If already The comet o2,.,e&.-
ences such resistance in passing through
the corona when at its nearest TO tn
sun that its period undergoes q n1arle.;
diminution, the effect must of necasslt"
be increased at each return, and afterv
few, possibly one or two, circuits Tie
comet will be absorbed by the SUI.
It Will be remembered that Sir l aac
Newton recognized the possibility That
it might happen to a comet, having snch
an orbit as that of the comet OF 1880
generally known as Newton's comctl.
and that he had considered the consc-
quences might be full Of danger 10 this
earth. Yet he only dwelt on the danger
arising, as he judged, from the addition
of so much fuel to the solar fires. We
now know that the real danger lies no-
from the absorption of SO much mater
as may exist in a comets head and M.
cleus, but from the conversion OF the
momentum Of the swiftly-rushing ma5s
of the comet into heat, the thermal
equivalent Of its mechanical energy.
have for my own part been long OF
opinion that the periodical increase of
such stars as Mira (the Wonderful sta1)
in the Whale, and Eta, Of the Argo,
is due 70 the motion OF some large comet,
followed by a metooric rain about
these two stars. have indicated fully
in my "Pleasant Ways in Science " The
reasons which induce ne to believe tlat
the outburst of the so. called "new star"
in the Northern Crown in 1866 is 10 hs
similarly explained. Without saying
that 1 consider there is absolute danger
of similar outburst in the case Of our
own sun when the comet Of 1913 shall
be absorbed by him Ga result which will,
in my opinion, most certainly take
place., will go SO far as to express NY
belief that if ever the day is to come
when 1.-THE heavens shall dissolve in
fervent heat" the cause Of the catastro-
phe viii be the downfall of some great
comet Oh the sun.
I believe the passage even Of The head
Of a comet over the earth would do lit
tie harm, for the simple reason that the
velocity with which the meteoric masses
forming the head would travel at the
earth's distance from the sun would be
too small to lead to any very mischiev-
GUS result. If the shower of meteoric
masses were very dense, the meteors
themselves being of the larger sort, and
so able to break their way through the
earth's atmosphere, the shower might
kill few Of the earth's inhabitants, or
even many hundreds. But there would
be no widespread destruction Of life.
It would be altogether otherwise, !
believe, if comet Of the larger SOFT fell
into or were absorbed by the sun. The
danger would be in the suns own
weight, not in the comet Or its attend
ant train. Tie bodies forming the head,
nucleus and train Of the comet would
fall il immense numbers, with enor-
nous velocity, and each with mighty
momentum on the suns fiery surface,
Possibly Gin my opinion probably their
most destructive work would be ac-
complished below that surface, under
the still more stupendous attractive en-
ergy OF that smaller, because more con-
denSpl Orh within uhinb 4,J-o 70 10