The evening telegraph. [volume] (Philadelphia [Pa.]) 1864-1918, 1870-07-06
SHOOTING STARS.


Pallas in Siberia, published in 1894, con-
sidered shooting stars to be exactly the
same as meteors frebals, or bolides, only
passing at great distances from the surface
on the earth. That distance he held to be
the only cause of the small apparent dimen-
sions they offer to our view. But observa-
ton has revealed circumstance which
prevents our adopting those notions re-
specting their real nature.
At certain epochs there occurs q con-
siderable increase in the number of shoot
ing stars seen within o given time. The
frequency of their appearance even becomes
30 great as to give it all the character of
a veritable shower of stars. Ii shooting
stars and bolides were really identical, the
latter, together with the showers of aerolites
which often accompany them, ought espe-
cially to show themselves at the same time
as the grand displays of shooting stars.
Now, nothing of the kind takes place. The
two sets of phenomena appear to have no
connection whatever with each other. Shoot
ing stars seem to be of nature peculiar to
themselves; and it is only by studying them
directly that we can hope to obtain informa-
ton respecting the cause of this curious phe-
nomenon.
No doubt, as soon as it is granted that me-
teors are solid bodies existing in space, which
the earth falls in with while revolving in her
orbit, it is very natural to admit that some
and to regard them also as betraying the pre-
sence of certain bodies in the portion of
space traversed by the earth. Neverthe-
less, the capital circumstance Just pointed
out, and from which it results that
meteors and shooting stars constitute two
distinct orders of phenomena, has raised and
left doubts respecting the real nature of
shooting stars. Some philosophers have per-
sisted in assigning to them a purely atmos-
pheric origin, and have even endeavored to
find in them clue to the meteorological
phenomena of which our atmosphere is the
seat. q Recent discoveries, however, have
removed all doubt upon the subject the at
mospheric theory of shooting stars must
henceforth be abandoned. We will sue
cinctly follow Mr.. Delaunay in his statement
of the clear and precise notions respecting
this matter which we now possess.
The first thing to be done, in the study
OF shooting stars, Is to ascertain their dis
tance from us. The observations required
for that purpose are very simple. Two
observers stationed at different spots suf-
ficiently distant from each other, will not
behold the same shooting star to be tracing
the same course across the armament. The
straight lines drawn from the two places of
observation to the shooting star will cross at
that point (namely, the shooting starr and
then diverge until they reach two different
points on the celestial vault Other circum-
stances being the same, the two points of the
celestial sphere which the shoot
ing star is projected at any given in
stant, for each one of the two observers,
will be the more distant from each other
the nearer the shooting star is to the earth.
Hence it will be easily understood that, by
certain calculations which there is no need to
detail here, the height of shooting star
above the earths sunface may be ascertained
from data, furnished by its simultaneous obser-
Of fvuo 10 fba
process as the method employed by astrono-
mers to determine the parallax of heavenly
body, and consequently its distance from the
earth.
The first observations in accordance with
this method date from 1898. They were
made by Brandes and Benzenberg, then
students in the University of Gottingen.
Until then, there existed no observations of
shooting stars; except that Bridone, in his
''Tour through Sicily" states that he saw
them exactly the same, from the summit of
Mount St. Bernard, in Switzerland, and of
Mount Etna in Sicily, as on the sea shore.
The conclusion was, that very considerable
altitude may be assigned to shooting stars.
BY comparing the different results obtained
between 179S and 1868, Alexander Herschel
(the grandson of William) found the average
height of shooting star above the earth to
be, at the commencement of its
appearance, one hundred and thir
teen kilometres, and at the end
eighty-seven. Mr.. Newton, of New Haven
United States arrived at the respective num-
bers of one hundred and eighteen and eighty
one Kilometres Father Secchi, of Rome,
found them to be one hundred and twenty,
and eighty kilometres respectively. The
agreement between these different results
is as satisfactory as can be wished. We
may fairly take Secchi's figures as repre-
senting in round numbers the average height
of q shooting star above the earth, at
the beginning and at the end of its appear
ance. Those figures, reduced to English
miles, also in round numbers, are seventy
five and fifty respectively. Seventy-fVe
miles above the earths surface being
not an extreme but an average height, it
must be allowed that the first appearance of
shooting stars occurs at a very considerable
altitude.
The velocity with which shooting stars
move is more difficult to determine than
their distance from US. 1t is certain that
their speed is great, compared with the
velocities which we have occasion to observe
on the surface of the earth; but the numerical
value of that speed still remains so in
determinate that it is absolutely i'm
possible to make it the base of any con-
clusions. 1t cannot be employed for de-
termining the orbit described in space by
the moving body to whose presence the phe-
nomenon is due. Nevertheless the deter
mination of that orbit is very important, and
it will be easily understood that observers
have turned their attention in that direction
When it is proposed to determine the orbit
of a new star, planet, or comet, the first
thing is to observe it as accurately as poss-
BILE, in three different positions. The data
furnished by these three obserya ions suffice