Vermont watchman and State journal. [volume] (Montpelier, Vt.) 1836-1883, 1847-01-28
THE REVELATIONS OF AS
TRONOMY.
From the North British Review.
COMETS

From tho North British Review
COMETS.
COMETS, or wandering stars, as they have
been called, are those celestial bodies which
appear occasionally within the limits of the
Solar System. They move in ellptical or
bits, in one of the foci of which the Sun is
placed; but unlike the planets, whose orbits,
excluding the asteroids, are never inclined
more than seven degrees to the eclptic, and
which always move from west to east, the
comets move in orbits inclined at all posi-
bic angles, and move in all possible direc-
tons No fewer than between SIR and seq
en- huRdred comets have been recorded, and
the orbits of nearly one hund,cd and forty
have been calculated; and as there are times,
when so far as astronomers know, there is
not one of these comets Excepting those of
Encke, Biela, and Da Faye) within the lin
its of the Solar System, their movements
must be principally executed within that vast
region which lies between thenearest known
fixed star Centauri, and the orbit Of the
New Planet, an interval equal to 5000 times
the distance of that planet from the Sun
What is their occupation there, or what it
is here, when they are our visitors, we can
not venture to guess. That they do not per-
form the functions Of planets, will appear
from the description of them which we shall
proceed to give, and there is no appearance
of their importing anything useful into our
system, or of their exporting anything use
full to another, Judging from the immense
portion of their orbits which lies beyond our
system, we are disposed to imagine that the
central body of some other system is placed
in the distant focus Of each Of their orbits,
and that in this way all the different systems
in the universe are, as it were, united into
one by the intercommunication of comets
Were our planetary system, with its 700 COM
cts, and probably as many thousands more,
to be surveyed from other external systems,
a mass ofunresolvable nebulous matter, mix
ed with stars, would doubtless be deserted by
powerful telescopes, and exhibit to us a pic
ture analogous to the nebulous combinations
by which astronomers have been so much
perplexed.
The most common aspect of comet from
xoHp, the Greek word for hair, is that of
faint round nebula, through which stars
are visible In advancing towards the
Sun the luminous matter becomes bright,
and at last shoots forth long train of light
called its tail After passing the Sun the tail
becomes shorter and shorter until it disap-
pears, and when the comet has receded to
certain distance it too disappears, even to
the most powerful telescopes. According
to Nj. Arago, there are some comets whose
luminosity is uniform, others which have a
nucleus or condensed portion which is some
times transparent, while there are other COM
cts which are more brilliant than the plan
cts, and whose nuclei there is reason to be-
lieve are Opaque and solid. The comet which
NJ Gambard saw pass over the Suns disc
was obviously an Opaque body. The origin
and nature of the tails of comets have excl
ted much speculation. Sometimes their tails
are only few degrees in length, and some
times they stretch even from the horizon to
the zenith. In some comets the tail is COM
posed ofstreams of diverging light, ofwhich
six have been counted, extending from the
nucleus nine millions of miles, and all of
them bent in the same direction These
streams vary in number and length in the
same comet, as was seen in the comet of
1925, when observed at Paramatta. Mr..
Dunlop assures us that the tail underwent
not only continual but periodic changes, in
dicating " rotation or regular succession
of the same appearances" performed in 10
: hours and SO minutes. The changes of f.
CURE were very sensible in a short time, and
/, "made their appearance generally at the
head of the comet, sometimes shooting out
from one tail, and sometimes from BOTH but
generally making their appearance first on
) the following side of the head" In the
splendid comet of 1911, which was visible
for ten months in this country, the tail, which
displayed rapid coruscatlons, consisted OF
two dverging beams of slightly coloured
light, inclined at an angle of about lS', and
a little bent outward. The length of the
tail varied from about 90 to 100 millions OF
4 miles. The nucleus of the comet was bril-
liant spot, estimated to be 500 miles in di-
D ameter, and it was separated from the inner
a surface of the surrounding disc by an inter-
$ val of 36, 900 miles. Nj. Chadni observed
4 in this comet certain undulatory ebullitions
rushing from the nucleus to the end of the
tail, distance of more than 10 millions OF
a miles, in two or three seconds of time."-
: The comet of 1924 Knocked the many theo-
: ries of cometary tails, by exhibiting twO tails
n Numerically opposite, the one on the Suns
u side being smaller and fainter than the other
h The first great comet of modern times
Z. was that which excited so much notice IN
: London in the month of December, 1850
: 1t continued visible for four months. Its
!, tail was 100 millions of miles long. Its dis
lance from the Sun, when greatest, was l27, )
e 900 times the distance of the Earth from the
Sun, and its velocity in approaching the Sun
/ was so enormous that it moved $50, 900 miles
in an hour, reaching, at its perihelion, tc
l. within l44 900 miles of the Suns surface
: a proximity so great that it may one day be
!, drawn into its devouring furnace, Sir Isaac
e Newton computed that its heat was then
o 1000 times that of red hot iron, from which
it would take million of years to cool !
J DIR. HALEY having been the first who obser'
G we'd this great comet, when he was travelling
a from Calais to Paris, endeavored to repre-.
S sent its motions by an elliptic orbit, with q
: period of SIS years Hence, he was led tc
= believe that this was the comet which terri
e fled the Romans at the death of Cesar, in
it the year Al before Christ, and which reap
y peared in A. d. 53l, and HOG, but this opin
d ion does not seem to be adopted by modern
astronomers, for Humboldt states that Enckt
has ascribed to it period of $500 years.