Evening star. [volume] (Washington, D.C.) 1854-1972, 1883-04-11
THE GREAT RED SPOT ON
JUPITER.
Recalling the Az0ic Age.
By G. D. HIscox.

The phenomenon of the now famous red spot
upon the surface of the planet Jupiter has
drawn the attention Of observers to an appar-
ent condition Of internal planetary activity not
heretofore observed, or only beginning to be
seen through the means of the great advance in
telescope power and definition lately acquired.
The intensity of this spot seems to be now
vanishing after duration Of about three and
a-half years, during which time observations
have been made of its physical appearance and
for the purpose of detecting any local or rela-
tive change of position. Also for the purpose
Of ascertaining the period of rotation of the
planet, as compared with the period heretofore
assigned from observations Of it's cloud spots.
The two periods of rotation are observed Ia
vary about So minutes; giving the rotation by
the cloud spots as 9 h. SO m. to 9 h. so m. g..
while the rotation by the great red SPOT was
found to be 9 h. IS m. "a s.
The times given for rotation by observations
upon different cloud spots also vary enough to
give us, together with the varying contour of
the cloud belts, strong evidence that what we
see of the planet Jupiter Is not the BODY of the
planet itself, but rather vast sea of cloud. pos
sibly Thousands OF miles in DEPTH kept afloat by
the intense heat of the body Of the planet.
From the we'll known laws of circulation OF
gases, vapors and cloud masses, as illustrated
by the circulation Of the atmosphere, together
with the progress and direction of the great
storms. cyclones and t0rnadoes upon the earth,
and as are beginning to be calculated in the
cyclontc action of the sun spots, according to
Faye's theory, which best meets the conditions
deduced from spectroscopic observations. we
cannot do otherwise than come to the conclu-
sion that the solid body of Jupiter has never
been seen-that our observations are only of the
surface OF vast envelope of cloud, that by it's
rapid rotation is constantly creating and keep
nlnfiO IL,
winds and equatorial doldrums, upon q vast
scale.
In this connection we have only to carry our
minds back to the beginning of the Azoic age Of
our world. and to imagine the surface just crust
ing over and still red hot in zones with our
entire oceans hanging as a vast cloud above. and
precipitating It's dense vapors as rain upon the
not and kissing surface 1t was then that the
activity of natural forces were at their height.
1t was then that the upheaval Of the intensely
from above, and produced the same class of
phenomena that has lately been observed. upon
vastly larger scale. upon the planet Jupiter.
II, in view of the low density which has here
tofOre been given for Jupiter, we can reasonably
accept an atmospheric or cloud depth OF eight
or ten thousand miles, the apparent great diam
eter OF the red spot may be assumed as only the
lrradiation to, and illumination of, the deep
cloud stratum by on igne0us mass, much smaller
imam the apparent size Of the red spot, as we see
1t from the earth.
The size of the great spot, 20 600 by 5000
miles, may be, for a planet g, 600 miles in di-
ameter, only the illumination OF a reasonable
upheaval OF the highly heated mass Of the inte-
rior corresponding with the remains of such
masses upon our earth. 3,
The apparent retrograde motion think is il
iusory for see no tenabe reasoning to sustain
the theory that has been advanced that it is a
floating island. or crust floating upon liquid
surface. Nor does there appear any good reason
Tor regarding 1t as of a periodical character, or
bearing anyrelation to other periodical physi-
cal phenomena as suggested by the Dearborn
observer. But, on the other hand. an assertion
IN the report of the Dearborn observations. that
the apparent center of the red spot does not CO.
incide with the true center. except when on the
central meridian, goes far to explain the theory
that the red spot, as seen by the telescope is an
area OF the outer cloud stratum illuminated by
an 1gneous mass upon the body of the planet.
And also that it's diurnal rotation should be fixed
by the observed rotation of the red spot, instead
OF as heretofore by the rotation OF the cloud
spots.