The semi-weekly messenger. [volume] (Wilmington, N.C.) 1897-1908, 1897-07-06
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In point OF briIliancy Jupiter has only
n competitor and superior among the
starry hosts. and that is Venus. II
reached its point OF opposition TO the
sun February 23rd, and now rises in
the early evening and will continue to
be an evening star until the middle OF
August. On September 18th it will
reach its point Of superior conjunction.
At that date IL viii be 515. 000. coo miles
from Us. Its present distance is about
400, cee. 900 miles.
Jupiter requires about twelve years
TO make a journey around the sun.
therefore, IL an old gentleman here on
earth had lived in Jupiter he would be
a youth Of six ummers 1t IS a law
governing the planets in their annual
journey that the longer the journey the
more deliberate their gait. Thus Mer-
curry has the shortest journey. but IL is
a rustler. averaging more than twenty
fve miles a second. Our earth. with
a longer trip, slackens her speed to
about nineteen miles a second. Jupiter,
with his long oyage before him.. takes
a gait of eight miles a second; Nep-
tune, with an annual journey of more
than 5000, 900 miles before him, as If
Xix lEGSSSIks u AUS pdfAIAIs
his strength, gets down TO a gait of
three and a half miles a second.
Very appropriately Jupiter is known
as the giant planet. 1t is larger h a
all the other planets combined. Its
equatorial diameter is a little more
than $4,000 miles. 1t is far more fiat
tended at he poles than our earth. The
equatorial and polar diameter of the
latter varies only rwenty-six miles,
while the variation of Trrnjyar ;S : nn0
miles. As its diameter is eleven times
that OF our earth, its relative size is
found by cubing eleven, which gives
us 1881.
While Jupiter is SO sluggish and so
much slower than the earth in it's mo-
ton on it's yearly journey, yet in a
contest Of speed in daily motion on its
axis, it makes the earth hide it's head.
1t makes the rotation in ten hours. A
point on its equator will travel a mile,
While a point on our equator will 60
about eighty yards. If a point on our
equator should move with such a We
lOcity, there would be only about thir-
ty minutes from sunrise to sunset. But
there would be no one in the region Of
our equator to see the sun rise or set.
Everything movable in that region
would be hurled off INTO space by CEN
trifugal force.
Although in size Jupiter is four hun
dred times larger, yet in relative dem
slty 1t is only One-fOurth that of OUr
earth. In volume il would make 1.4OO
earthS; but to mak them as dense as
our earth. we should have a little more
than three hundred. This lack of den
sity on the part of Jupiter is what we
might expect from the nebular hypoth-
esis. AS a rule, the density of planets
increases as their distance from the
sun decreases. Though the relative
density of Jupiter is so much less than
that of the earth, yet because of it's
regular mass the attractive force for
bodies on it's surface is far greater thar
on our earth. Thus, if a girl of 16
should weigh one hundred pounds here,
if transferred to Jupiter she would
draw the scales at 260 pounds. How we
ascertain the comparative weight of a
body on the surface of Jupiter. Gravity
or weight is directly according to the |
mass, and inversely as the qua Of
the distance. The distance in such a
calculation is the distance from the
surface to the centre of the planet. The
mass of Jupiter is 316 times that Of
the earth. From this alone a body
would weigh 316 times as much on the
surface of Jupiter as on the earth. But
the matter of distance hange this
very materially. From surface to GEN.
ire Jupiter is eleven times greater than
our earth. The square of this gives us
121. Here, You see, the earth has the
decided advantage. If distance alone
be considered an object on our earth
Jupiter. We obtain the ~relative sur
face gravity by dividing. which gives
us about 22-3 in favor of Jupiter.