The Hawaiian gazette. [volume] (Honolulu [Oahu, Hawaii]) 1865-1918, 1872-07-31

The GIANT PIANET.-Jupiter has diameter
exceeding the earth's rather more than ten times,
and a volume exceeding hers ,230 times. 1t is
not far from the truth TO say that Juplters di-
meusions exceed the earth's in very nearly the
same degree that those of the sun exceed Jupi-
/ ter's But his mass, though gigantic compared
with the earth's, does not altogether correspond
( to his bulk for it exceeds the mass Of the earth
only 300 times So that, If the disc our astrono-
mers see and measure actually represents the true
globe Of the planet, bis substance must be, on
the average, much less dense than that of the
earth. In fact, while the earth's density is
" six times as great as that Of water, the density
Of Jupiter thus Judged would exceed that Of
water BY barely one-third. This vast globe rota-
ties in less then ten hours, on an axis nearly up
right or square to the level in which the planet
travels. This rapidity of rotation-so great that
points on the planets equator travel twenty
seven times as fast as points on the terrestrial
equator-results in considerable fattening Of
the planets globe insomuch than the polar da-
meter is less than the equatorial by about a
twelfth part, or by fully 1000 miles. And it may
be remarked in passing, that this circumstance
the fact, namely, that the poles of the planet are
drawn in, as it were $500 miles as compared with
the equatorial regions, or l,75O miles as compared
with the mid-latitudes in either hemisphere-af-
fords a striking illustration of the enormous
amount of energy really represented by the rota-
ton of Jupiter. 1t may also be added that the
velocity with which points on Jupiters equatori-
al zone are carried round exceeds the correspond
ing velocity in the case Of all the planets IN the
solar system, and is nearly six times greater than
the equatorial velocity Of the sun himself 1t
amounts in fact to about seven and half miles
per second
We do not propose to consider here at any
length the system of satellites over which Jupi-
ter bears sway but this preliminary sketch would
be incomplete without few words on the subject.
1t is worthy of notice that although our earth IN
some sort resembles the outer planets in being
by a satellite, yet the relation which
our moon bears to the earth is altogether differ
ent from that which the satellites of the outer
planets bear to their respective primaries. Our
moon is by no means minute body by compar.
lson with The earth, and compared with Mars or
Mercury she may be regarded as having very re-
spectacle dimensions. We may, indeed, look
upon the moon as fifth member of the inner fam
lily Of panets-a member inferior to the rest,
doubtless, but still not far inferior TO Mercury as
Mercury is inferior to the earth In the case of |
the outer planets however, and especially in Ju-
pliers case, moons hold an utterly subordinate
position. Taking the accepted measurements,
we find the largest of Jupiter's moons less than
he l6,OOOth part of its primary as respects bulk,
while its mass or weight is less than the II OOOth
1art of Jupiters. So that these orbs may fairly
De regarded as bearing the same relation to their
primary that Jupiter himself bears to his primary
the SUBTLE CoymhW Magazine