The Washington herald., 1909-05-09

eye
TIE chances OF the earth ever coming to
serious harm from collision with this
comet or any other are extremely small.
As tine has gone by science has more
and more divested this favorite theme OF
its one-tine terrors-
Once the thought OF a comet striking
the earth was one which stirred fear IN
the hearts OF the bravest men. The an
pesrance Of comet in the heavens sent
men groTelfng abjectfy to the earth
But nowadays men talk quite calmly Of
the chances OF a comet striking the earn
and they can discuss without undue treua-
ors the probable results OF such q COL
lision.
No Cause for Alarm.
The earth has before now psssea
through the tail Of a comet and there uss
no damage done. Scientific men havs
noted that the sunsets were more b-sI-
liant That vas all
But the tail Of a comet is made I'd Of
gases The head is OF solid matter.
Should the earth collide with the head OF
q comet the results would be far more
serious. but they might not be much
greater than a mere meteorlc shower at
that
Writing on this theme. DR.. Charles A.
Young, professor OF astronomy az Prince
ton and a writer and scientist Of estab-
lished position. said IN one Of his works:
1T has been supposed that comets
might do Us harm 10 Two Tays-either by
actu.lly striking the earth or BY falling
into the sun and thus producing such an
increase OF solar heat as 20 burn Us ID.
As regards the possibility OF q collision
with a comet, II is 20 be admitted that
such an event Is possible. In fact, Il the
earth lasts long enough, il IS practically
sure 10 happen. FOR there are several CON-
cts orbits which pass nearer to the
earth's orbit than the semi-diameter Of the
comets head. and at some time the earth
and comet VIII certainly come together.
Such encounters viii. however. be very
rare. IF we accept the estimate Of Babinet
they viii occur about once 81 15,00600e
years In the long run.
May Poison the AR.
"As TO the consequences OF such a col
liEion IL is impossible 20 speak with conf
dence for want OF sure knowledge OF the
state Of aggregation Of the matter. com
posing a comet Everything de-
pends on the size OF the separate solid
particles which form the main portion Of
the comets mass
IF they weigh tons. the bonbardment
experienced By the earth when struck ~
q comet would be a very serious mstteF1
II. as seems more likely, they are, for the
most part, smaller than ninheads. the re-
suit woulS be simply a meteoric shower.
AS regards the effect OF the faIl OF q
comet Into the sun, Il may be stated that,
except in the case Of Eucke's comet, there
IS no evidence OF any action going on that
would cause a now existing Periodic
comet 70 strike the sun surface: Il IS.
however. undoubtedly possible that a
comet may enter the system from with
out, so accurately aimed that it VIII hit
the sun.
But II a comet actually strikes the sun
Il Is not likely that the least harm viii Be
done. There might and very Ike
i would be q fash OF some kind Al the
solar surface, as the shower OF cometary
particles struck It, but probably nothing
that the astronomer would not take de-
light II watching.
a danger OF q different sort has been
suggested. thar II comet were 20 strike
the earth our atmosphere would be p0is-
oaed b. the mixture with the gaseous
components Of the comet Here again the
probability is that on account Of the low
density Of the cOmetary matter no sufTf-
cient amount OF deleterious vapors would
remain in the air 10 co any mischief az
the earth's surface"
Its Eternal Hurry.
Hslley's comet IS one OF those bodies
whose path through the heavens is sup
posed 20 be IN the form OF an ellipse, and
the greatest velocity Of the comet IS when
it IS In the middle OF the eIlipss-
According 20 the calculations OF its dis
coveTer the comet moves in an orbit. ths
other end Of which Is far beyond the Orbit
OF Neptune. the outermost planet Of the
solar system. and & little more than 2So0.-
GOO miles beyond the sun
At the far end OF its orbit the comet
joys along at the comfortable rate OF
about Ss miles an hour.
As It strikes into the home stretch. so 70
speak. Its speed increases until. when il
begins TO Tevolve around the sun Just
after It has flashed past the EARTH and
when il Is visible 70 the esTth. its speed
is about 900 miles q minute
The chief interest OF HaIley's comet,
spectacular OF all the heavenly bodies. Is
that Il was the first comet whose return
was correctly predicted.
In 16S2 HALEY, 2 brilliant young English
astronomer and an associate Of Newton,
computed It's orbit by a system which he
himself invented and made the following
assertion Il dare TO venture 70 foretel
that It viii return again n I75s. II L
should return then candid D0steritv will
not refuse TO acknowledge that this was
first discovered By an Englishman."
The comet did return in I75S, just z few
years after HALEY had died, and the
memory OF the EngIishnan who had pre-
dicted its appearance was peTpetuated bY
having his name tackled to the comet.
Something About HALEY.
Haley, the discoverer OF the orbit Of
Halley's comet. was born IN England in
1859 OF thereabouts. He died al the aga
Of 50 years He had brilliant mathemsti-
cal powers and before Newton published
his law gravitation Re had discovered for
himself. the facts upon which this law ID
based.
Accidentally discovering that Newton
was preparing 70 publish such a law on
the eve Of the publication OF his own re-
searches and that Newton had preceded
him into the field. he generously turned
over all Of his own notes to his fellow
worker and completely subordinated his
own work TO the other.
There has rarely ever been a case OF de-
votion TO science more disinterested OF
more generous When he died he was the
foremost scientist OF his time.