The Milan exchange. (Milan, Gibson County, Tenn.) 1874-1978, 1875-05-20
The Planet Jupiter.

The planet Jupiter. the largest in the
solar system, Is now avery prominent OBJ
iect in the evening sky. He comes to the
meridian near IL O'Clock. having been in
opposition to the sun about two weeks
since.
it is not necessary to give directions for
finding him, other than that he Is the
BRIGHTEST star visible east from the south
ern line; but a note of his position with
reference to a few stars may serve as
help to recognize them. when the planet
has left their neighborhOod.
A little to the right of Jupiter, and
sOuthing about o'clock in the evening, Is
a very pretty figure-a trapezlum-oi
stars, the upper side OF which may De
roughly described as seeming to be acOuC
ward across. This figure is the eonstei-
latiOn COrvus. the Crow. a line from the
two upper stars to Jupiter Will pass
through a bright star, usually classed as
of the first magnitude. 1t is the principal
star in Virgo, the Virgin, or the CLEANER,
and is represented on the globes as IN a
handful of corn carried by the female:
Hence the stars has been called Splca, ana
Azimech. It is also called Arlsta not
from the Greek word meaning "the best,
as some may suppose, but from a word
signifying the spike of an ear of corn, or
the ear itself.
The constellation Corvus, with IFS four
DrincipaI stars, and two other outlying
ones at opposite corners of the t0ur-sided
figure, is very easily recognized, when
once the observer has identified IL IN the
sky.
The planet Jupiter has been written
about so much recently that we scarcely
need ESSAY another description. We may,
however, note briefly the results OF the
latest quantitative research, differing con-
siderably in several respects from the gen
orally accepted statements OF the text
books.
The mean distance of Jupiter from the
sun is AZ, 100000 miles, or a little more
than 80 times the mean distance OF the
earth from the sun. He travels through
space (arOund the Sun) at the rate OF lit
tie more than s miles per 81 cOnd. His
equatorial diameter is $3.50 miles, or los
times that of the earth. His volume IS
1227 6 times that of the earth. His weight
(maSs) compares with that of the earth as
305 p to to that of the earth plus the
moon as 30l .56 TO l I; and to that of the sun
as l to / ,04S nearly.
Jupiter is attended by four satellites,
the respective diameters of which are
1850 miles, 2, 10 miles, 3,44S miles, and
1850 miles. All but the second are larger
than our moon. The third shines as q
star of the sixth magnitude, and could be
seen with the naked eye ifit were not
partially obscured by the superior bright
ness of the planet.
A great deal has been written within the
past few years about the great changes
observable in the atmosphere OF Jupiter,
and the fact that he reflects to us so mucn
light that his temperature must be only
little below the point necessary to self
luminosity 1t is believed that the planet
is too hot to permit on his surface any OF
the forms of life with which we are
acquainted and this belief has been writ
ten up in such a wav, or ways, as TO lead
many people to think that the idea Is
original with some astronomer OF the
present generation. 1t is refreshing to
turn to the works of the eminent natural
it, BuffOn, who fiOurished more than
century ago, and there find the whole
speculation spread cut in absolute terms.
Button calculated that the planet had
occupied 8, 400 years in cooling TO the solid
condition: that he would occupy 10000
years more in cooling down to the point
where his surface could be touched; of
which period at least 1000 years are yet
l1leEDired that 2I0. 400 years more would
be required TO cool the planet down to the
temperature of the earth; and that still
another 4S3 900 years must elapse before
the planet would be chilled down to the
present condition of the moon.
Button calculated further, that three OF
the satellites of Jupiter are already died
out worlds; that one of them 1.-THE larsesO
is far advanced in the frigld phase; and
that Saturn will require 1900 years
longer to cool down 10 the present cOndi-
ton of the earth.
This is pretty good philosophy for
man who died only seven years, after
Herschel first turned his telescope upon
Uranus, long before the spectroscOpe was
invented, or the law of the correlation of
forces discovered. Had Button lived till
now he would undoubtedly have revised
his figures in the light of more recent
knowledge; his periods are too short. But
it is due to him to say that he anticipated
important deductions which have been ac-
credited to modern scientists and that his
estimates of the present relative tempera-
lures of all the then known planets were
81 bstantially the same as those wa ranted
by the observations of the last few years.
was not far wrong when he re-
marked that There is nothing new under
the sun. Chicago Tribune.