The Indianapolis journal. [volume] (Indianapolis [Ind.]) 1867-1904, 1901-12-01
WHY THE M~ETE0RSFAILED
REASON TOLD BY SIR ROBERT BALL,
BRITISH ROYAL ASTRONOMER.
Shooting stars, What They Consist of,
and Why They Fly Through
Space at Great Speed.
New York Special.

land, the greatest living authority on as
tronomy, in the Glowing article explains
why the -long-expected showers of meteors
failed to appear on Nov. 10 of this year.
Sir Robert is now in America for the pur-
pose Of delivering a series Of lectures at
Harvard University. His writings have
done more than those of any other scientist
to popularize the study of astronomy. Sir
Robert writes:
THE middle of November is always a
time of special interest to the watcher of
the skies. If he is favored with clear
weather he may count with reasonable GER
tainty on seeing something in that most in
teresting group of shooting stars which is
known as the leonids,' while, if he is really
fortunate enough to witness a display of
this group under the best conditions, he
will be rewarded by one of the most sub
lime spectacles which it is possible for the
eye of man TO behold.
Let us first briefly think Of what a
shooting star really consists. 1t may seem
hard TO believe that one of these objects
which streams across the sky with a flash
bright enough to call forth an exclamation
from every beholder is really quite a small
body. 1t may weigh an ounce or less; it
may very often be no larger than the stone
in a signet ring. Even a grain of sand
would be large enough to form an appre-
ciable shooting star. This little object is
moving through empty space with a speed
about one hundred times as great as that
of the swiftest bullet that was ever fired
from a rifle.
For uncounted myriads of years il has
swept along it's path until at last the su-
preme m arrives. In the course Of
it's journey it encounters the earth-or,
rather. the atmosphere which surrounds
the earth. By this plunge into our air the
speed of the little object is checked, but
the friction against the air is so great that
the object presently becomes warm and
red-hot and white-hot.
HEAT CAUSED BY FRICTION.
The heat generated is indeed so great
that even if the little body were composed
of material as refractory as flint it would
be driven into glowing vapor just as if it
had been heated by the electric arc. Thus
in a brief fraction of a second the little
missile has been raised from a temperature
hundreds of degrees below zero up TO a tenn
perature which transforms it's path into a
brilliant streak. Such is the Phenomenon
OF a shooting star.
In its long wanderings the little object
Is not alone; II is accompanied by other
similar objects. They are in fact present
Al ohOdlS VI uuCOuHleu ana unCOuntaDle
myrlads. When the earth in it's journey
happens to encounter such a shoal then a
corresponding number of shooting stars are
near. And If the part of the shoal through
which the earth passes happens to be a
very dense one then the beholders enjoy
one Oh those superb spectacles such as
many of us remember SO we'll in 1866.
1T cannot be denied that much disap-
pointment has been felt during the last few
years at the absence of one of these grand
scenic displays. 1t was certainly expected
IN " ann az 4 Z dt1 not Tnan H. -
were grounds for believing that it might
appear in 1890. / do not, however, think that
any one who had studied the subject held
out any expectation that the display which
failed in 1899 and failed in 1900 would never
the less make itself visible in 1901.
1T is generally admitted that the time
mas now passed by, and though there may
no doubt be the usual November displays,
yet L do not think that there is the least
reason TO expect a great display for thirty
years; indeed, after our recent experience
l doubt II many astronomers will have the
harulhood to express any sanguine expecta-
tons even when the thirty years have
elapsed. There is, however. no need to dis
cuss that before the present generation.
Our object now is the much simpler one of
explaining, II we may, how the reasonable
expectations OF the great shower within
the last Few years have remained unful-
filled.
The great shoal of meteors follows a GER
tain track through space. 1t moves along a
grand celestial highway around the sun. and
ii accomplishes each journey in a period of
thirty-three years. The shape of the shoaI
is remarkable; IL is very long and thin. The
form OF the great body OF meteors has been
well hkened to a piece of silk several yards
long. The shoal is many thousands of
times as long as it is thick, so that i'm pass
ing any point the shoal would appear as a
long, thin procession. Indeed, it is so long
that, though the meteors move, as | have
said, about one hundred times as swiftly
as a rifle bullet, they would take quite two
years to pass by.
I'VE are then to think of the meteors as
revolving around the sun in a long, oval
figure. the thickness of the shoaI being so
lnconsiderable In comparison to the size of
the oval, that if the oval be as big as could
be drawn on this page the shoal would have
10 be represented by the tiniest line which
can be drawn. This highway I'm which the
leoni6s move lies in a plane, but il is bv no
means the same plane as that in which the
earth revolveS.
TRACKS OF THE METEORS.
THUS we see that the track of the earth
is a circle in one plane, and that of the
meteors is an oval in another plane. The
earth - so small in comparison with the
size or its orbit that it's path is also repre-
scented by an extremely fine line. We can
now consider the conditions under which
the shooting stars will be visible to us
There is evidently one important condition
that must be fulfilled If we will recollect
that to see the leonids they must actually
strike the earth's atmosphere.
IF the whole shOal passed just above the
atmosphere we could see nothing whatever
of them, even with the most powerful tele-
scope. 1t is therefore essential that the fine
and delicate line which indicates the track
of the meteOrS must interSect the fine and
delicate line which marks the track OF the
earth. n little consideration of this fact
shows that the wonder will be not that We
occasionally miss seeing a great shower at
the anticipated time. but that we can see
such a display at all. on that occasion in
1866 when the magnificent show of leOniCs
was such as TO form a life experience for
everyone who saw it. these two orbits did
just as the earth arrived at the crossing
the procession of meteors was in the act
OF passing. The earth, therefore, plunged
right through the procession. Untold
myriads of shooting stars struck into the
atmosphere from which they We're never TO
emerge, for. of course, each such object.
when transformed into a streak of fire,
loses it's solid form and subsidies quietly as
dust through the atmosphere.
when thirty-three years had passed
since November, 1866, there were grounds
for hoping that there would be a recur-
renee of the display. The earth was. in the
middle of November. 1899. again in the same
The shooting stars had been allowed thir-
ty-three years in which TO make their cir
cult. If their track had remained in the
same place We should unquestiOnably have
repeated in 1899 the grand experience of
1866. But the track OF the shooting stars
had swerved. 1t had been bent aside suf-
fciently 10 escape actually crossing the
though we We're assured that the stream
of leonidS were In our vicinity. yet its dis
lance was far enough to enable them TO
escape that fatal net which the atmOs-