Sunbury American and Shamokin journal. [volume] (Sunbury, Northumberland Co., Pa.) 1840-1848, 1843-03-18
The supposed Comet, no, n Comet.

which has been observed for several evenings
past in the heavens, in q south-westerly direc.
ton, about seven o'clock, has been supposed by
mauy to be the tail of comet. That this sup.
position is mistaken one is clearly shown by
the following article, which furnishes a correct
scientific description otthe phenomenon, which,
;toppears, was noticed and described by scicn.
tfc men nearly two hundred year ago;
From the National Inteuigencer.
XODIACAL LIGlIT.-Ths interesting
phenomena in the heavens was noticed here on
Monday night and also on Tuesday and We'd
nesday nights.
Iodiacal light appears in the morning before
sunrise, and in the evening after twilight 1t
is n pyramid, with the sun for its basis The
sides are not straight, but curved, as those ola
lens when viewed edgewise Ii ia generally
| seen about the period ofthe equnoxes, when
there is the shortest twilight. This light re-
semblesthe milky way faint twilight or the
tail offs comet The intensity ofthe light, its
shape and tints, may be varied according TO the
condition otthe atmosphere, which is now re.
mark lblc tor its clearness
! The zodiacal light was first described about
! two centuries ago, and the various theories reg
! pectng it may be seen by referring to works on
astronomy.
The subioned description ofthis light, which
we copy from the Encyclopedia Americana,
will we dare say, be acceptable to our readers,
and especially to those who have alarmed them
selves with the apprehension that this atmos.
pheric phenomenon was COMET, such as
terror sheds
On gazing nations, from his fiery train
| OF length enormous
"ZopACAL LidiI1 a triangular beam of
light, rounded u little at the vertex, which is
seen at certain seasons of the year, before tho
rising and after the setting of the sun. 1t re-
sembles the faint light of the milky way, and
has It's base always turned toward the sun, aud
its axis inclined TO the horizon. The length
of this pyramidal light, reckoning from the sun
as its base, is sometimes 45o, and at others
1902; and the vertical angle is sometimes 26o.
and sometimes l0o 1t is generally supposed
to arise from an atmosphere surrounding the
sun, and appears to have been first observed by
Descartez and by Childrey in 1859 but it did
not attract general attention till it was noticed
by Dominique Cassini, a. W who gave it its
present name. II we suppose the sun to have
an atmosphere, as there is every reason to be-
lieve from the luminous aurora which appears
to surround his disc in total ecipses, it must be
very much flattened at its poles, and swelled
out at the equator, by the centrifugal force Of
his equatorial parts. When the sun, then, is
. below the horizon, portion of this luminous
atmosphere will appear like pyramid of light
above the horizon. The obliquty of the zod-
acal light will evidently vary with the obiiqu-
ty of the suns equator to the horizon and in
the months of February and March, about the
time of the vernal equinox, it will from very
; great angle with the horizon, and ought there
FORE to be seen most distinctly at that season OF
the year. But when the sun is in the summer
solstice, he is in the part Of the ecliptic which
parallel to the equator, and therefore, his c.
quator, and consequently the zodiacal light 10
more oblique to the horizon. Laplace, howe
:, vGr, has made some objections 10 this theory in
8 his Necanique Celesis +, and Regineer is of o.
=, pnion that it is owing merely to the retraction
, of the solar light by the earth's atmosphere"