The Jasper weekly courier. [volume] (Jasper, Ind.) 1858-1922, 1872-07-26

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Jupiter has q diameter exceeding
the esrth's rather more than ten times,
and . volume exceeding hep ,23O
times. II is not far from the truth to
say that Jupiter's dimensions exceed
the earth's in very nearly the same de.
gree that those Of the sun exceed Jupi-
ter's, But his mass, though gigantic
compared with the earth's, does not al
together correspond TO his bulk, for II
exceeds the mass Of the earth only 800
time So that, if the diss our astrono-
mers see and measure actually repre-.
sents the true globe Of the planet, his
substance must be. on the average much
less dense than that Of the earth. In
fact, while the earths density Il nearly
six times as great a. that Of water, the
density of Jupiter (thus Judged would
exceed that of wster by barely one
third. This vast globe fotates In less
than ten hours, on an axis nearly up.
right or square to the level in which the
planet travels. This rapidity Of rota-
tion-so great that points on the plan
cts equator travel twenty.seven times
as fast as points on the terrestrial equa.
tor--results in considerable Aattening
of the planets globe; insomuch that
the polar diameter is less than the equar
torial by about a twelfth part, or by
fully 1000 miles. And it may be re-
marked the passing, IT. 1t this circuna.
stance-in fact, namely, that the poles
of the planet are drawn in as it we're,
800 miles as compared with the equa.
torial regions, or 1850 as compared with
the the mid.latitudes in either hemis-
phere-affords striking Illustration of
the enormous amount of energy really
represented by the rotation Of Jupiter.
1t may also be added that the velocity
with which points on Jupiter's equato-
rial zone are carried round exceeds the
corresponding velocity in the case Of all
the planets in the solar system, and 10
nearly six times greater than the equa-
torial velocity of the sun himself. 1t
amounts, in fact, to about seven and a
half miles per secondi N.N g.t
We do not propose to consider here
at any length the system of satellites,
over which Jupiter bears sway; but
this preliminary sketch would be incom-
plete without a few words on the sub
ject. It is worthy Of notice that al
though our earth in some sort resem-
bles the outer planets in being accom-
panied by satellite, yet the relation
which our moon bears to the earth is
altogether different from that which
the satellites Of the outer planets bear
to their respective primaries. Our
moon Is by no means minute body by
comparison with the earth, and com.
pared with Mars or Mercury she may be
regarded as having very respectable di-
mansions, We may, indeed, look upon
the moon as fifth member of the in
ner family of planets-a member in.
ferior to the rest, doubtless, but still
not far inferior to Mecury as Mercury
is inferior to the earth. In the case of
the outer planets, however, and espe-
cially in Jupiter's case, moons hold an
utterly subordinate position. Taking
the accepted measurements, we find the
largest Of Jupiter's moons less than the
6,OOOth part of its primary as respects
bulk, where its mass or weight is less
than the IL ,O0Oth part of Jupiter's. So
that these orbs may fairly be regarded
as bearing the same relation to their
primary that Jupiter himself bears TO
his primary-the sun.--CWnhiH.