The Pickens sentinel. [volume] (Pickens, S.C.) 1871-1903, 1882-11-30
The Mystery Of comets, Tails.

Z 1 ~
The eometary Displays of the last two
years have excited in an unusual degree
the spirit of astronomical SPECULATION
as to the causes of comets tails and
their mysterious movements! An Tn
giish scientist in the PhiLoSot htcal Ma0-
Uzfnc propounds novel theory to ey-
plain these phenomena. The forces on
which he relies to make out his theory
are the force of gravity which urges
the comet toward the sun, the expansive
torce Of the sun heat, and the resist
ance OF an Invisible atmosphere sur
rounding The sun at immense distances
lhe cha Iges in comet which give rise
to IT'S t il Gegin with the emission of gas,
IN the d rcctioh determined by the ex-
pansive force Of the suns heat acting
on the comet. But soon these lets bend
round, as. If carried back by strong
w'nd, forming an envelope round the
Dody or the comet and cone behind
1t, rs would happen to a man dressed
IN q loose robe and running RAPIDLY
aginst the wind, The jets of gas os-
Gaping tom the body Of tho comet an |
expanding when they leave it are moro
resisted by the suns atmosphere than
ITS more solid heat, so that they seem
to tall behind it, forming tho comet s
envelope and coaicul form behind the
head. According To this view the bo lv
OF the comet is constantly moving
through the vapors it throws Of, and
thus produces the appearance of u to |
by leaving each successive part thrown
| olf more and more behind it. A ter
PAS sing its perikelion the comet carries
lis tai before it instead OF behind it. he
says, because while moving toward the
sun it is perpetually passing from u
| rarcr into denSer med um, while in
rel eding from the sun it is peri ctually
pass ng lrom dcnScr into q rarer me
dunn.
The fact that the most rapid altera-
| ton in the direction OF comets tails
| necessarily o. ours just when the cxDan-
sire force OF the sun heat is most let
gives plaus.bility to this hypothesis.
There can be little doubt that, sc Mr..
HugginS observes: "If we could soc Il
great comet during its distant wander.
| ings, when it has put of the gula trap
pings of porhelion excitement, it wouid
| appear as very sober object, and con-
st of little more than nu .lcus alonc.n
The same may perhaps be said OF the
M s,erious wanlercr while approaching
the sun, but not near enough to under
&C va"or!zation from tho solar heat or
| encounter the denser strata of the
invisible solar atmosphere. The re ccnt
inquiry OF DR.. Siemens into the con-
| scrvation OF solar energy also lends COL
or TO the theory that comets when near
the sun may encounter a resisting medi,
um, which would account for the phe-
nomena in question as the writer re-
ferred to supposcs. But astronomers
| arc yet far from solving the old prob
| !ems of the origin and eccentric be-
| havior Of comets tails. There seems
to be- says Mr.. Hugg'ns, "a rapidly
| growing feeling among physics stS ,hat
both the suli.light OF comets and the
phenomena of their tails belong TO the
order Of electric phcnomcna." This
view, in order to account for the carry
ing away of the comets tai under an
Gle. trio repulsion oXcrted by the SIN,
necess tates the supposition that the sun
is strongly electrified, either positively
or negatively, and also that, in the
changes going on in the comet, the mat
ter thrown off by the nucleus has be-
come strongly electrified in the same
way as the sun. Otherwise the attrnc-
ton on one side of every particle OF
the comet would be precisely cQuai-as
| HerSchel points QUITO the rcpuSOn
on its opposite side, and we should
therefore be at loss to explain the
enormous velocity with which the mat
ter of the tai 8 carried backward, in
opposition both to the motion it had as
part OF the nucleus aud to that it ac-
| quired in the act Of its emission. But
| while all theories designed to explain
cometary phenomena have hitherto fall
Ell short OF the mark, they have served
to stimulate active investigation, and
also to throw important light on the
| physics of the sun and the diffusion OF
matter in intcrstcllar space.--M T.
| Herald.