Bismarck weekly tribune. [volume] (Bismarck, Dakota [N.D.]) 1884-1943, 1898-04-08
THE PLANET VENUS.

THE PLANET VENUS.
WHY WE KNOW so LITTLE ABOUT
THAT HEAVENLY BODY.
D.fusring Theories That Have Been Ad.
vanced Since the First Observation by
Cassini In 1888-The Opinion Of Camille
ILLUMINATION.
i The planet Venus is our nearest celestial
neighbor, the moon alone excepted. And
yet our knowledge of Venus, as compared
with that of Mars, is comparatively small.
This is not because of the lack of effort to
increase that knowledge, but to other
causes beyond our control, which are ex-
planned by Camille Flammnrion in Le
Bulletin de la Sooiete Astronomique do
France. M. Flammarion writes as follows:
"When Venus is nearest to us, with a
telescope magnifying 80 times only it ap-
pears as large as the moon as seen with
tho naked eye. An instrument which
magnifies 300 times exhibits Venus to us
ten times longer in diameter than tho
moon, and u magnifying power of 600
makes Venus 30 times larger than the
moon. Instruments which magnify thus
give great opportunities. for telescope
study, and they have produced marvellous
results in the case of Mars, a planet both
farther from us and smaller than Venus.
In the case of the latter planet We are as
yet not sure of anything.
''Tho reason of this is the difficulty of
observation. In the first place, since Venus
revolves around tho sun in al. orbit in
terror to ours tho time of its greatest
proximity is when it passes between tho
sur and us. Its illuminated hemisphere
is naturally always turned toward the sun.
There result phases analogous to those of
the moon. The nearer Venus comes to the
earth tho less we see Of its surface. The
farther 1t gets away from us tho more we
see of its surface, but the planet is reduced
to its smallest apparent dimension. A Sec
ond circumstance, not less deplorable for
the success of our studies, is that Venus Is
surrounded by an immense atmosphere,
twice as dense and much higher than ours.
The effect of this is that we never can be
! sure of anything we see OH Venus"
To demonstrate this NJ. Flammarion
gives q summary, which cannot be read
F, without amusement, of tho results of OBJ
servations of Venus during nearly $50
years: s'The first observer was Dominic
Cassini, at Bologna in 1866, who observed
what he believed to be a brilliant spot on
Venus, and this spot he continued to see
until his death in 1926. BY the recurring
appearance of this spot Cassini calculated
that Venus turned on its axis once in loss
than a terrestrial day and ~revolvcd in its
orbit in nearly 90 days. Cassini's son,
. 60 ~ 1~k,~ k~.,~ul kI.,% L., N-~ c,,,,
spots on the planet. Ills calculation
was that Venus rotated on its axis in
about 23 hours and 20 minutes. Early
astronomer, Bianchini, thought no discov-
cred u now set of spots, and he lcngthcncd
the time of the rotation of Venus on it's
axis to "a days 8 hours. Then Johann
Hieronymus Schrotor Q745-1S16) declared
that he had discovered IN Venus noun
tains six times higher than ~Chimborazo,
and he fixed the rotation of the planet on
it's axis at 23 hours 81 minutes. Sir Will
liam Herschol in his turn finally became
convinced that no one had ever seen spots
OF Venus, that what they believed to be
such were optical receptions. He declared
that it was impossible to discover tho
length of time taken by Venus in turning
on Its axis, and he ceased to make Observa-
tions of the planet. AS for the high noun
tains found by Schroter, Sir William
laughed ut him. Father do Vico and his
colleague. Palolnba, of Rome in 1889 made
more than 10, 200 observations of Venus
and ended by stoutly asserting that there
were spots on Venus, and they made the
time of rotation % hours 81 minutes and
81. 9345 seconds! %Schiapnrelli of our day
made up his mind in 1890 that Venus takes
1874 days and II hours to turn on its axis
that is to say, it takes tho same time
as to revolve in its orbit round the sun
presenting to the sun always tho same face.
"While, however, Schiaparelli has been
observing Venus a host Of observers in
various parts of tho world have also been
observing it. The list of them would be
long. One of tho most recent is MI. Bar.
nard of the Lick observatory, with it's i'm
mense telescope. He declared that he has
never been able to distinguish any certain
spot on Venus, save once, on May 20, 1889.
The combined result Of ull these observa.
tions is to delmolish completely the theory
of S~chiaparelli. According to all proba'
bility, the globe of Venus turns, invisible
to us, under its atmosphere, which turns
with it, but does not offer any fixed point
which will permit us to determine the
time Of this rotation.
"The atmosphere of Venus is SO dense
that its action is manifest when the planet
makes a transit across the face of the sun,
under the form of a black disk. By the
observation of a transit at Pueblo on Dec.
8, 1874, it was found that Venus has an
atmosphere five times higher than that OF
the earth. To sum up, I affirm that we
can know nothing about the rotation Of
Venus on It's axis, because the absorption
Of light produced by its immense atmos.
phere certainly prevents US from distin-
gushing any detail on the surface Of the
planet. The gray spots that are perceived
from time to time on Venus are effects of
contrast due entirely to solar light and In
distinct shadows of an atmospheric nature,
incapable Of furnishing any serious ground
for calculation as to the rotation of the
planet. No one on earth has ever seen the
surface of Venus, and no n ever will.
No one has ever seen a clearly defined spot
like those seen on the disks of Mars or the
moon. The maps Of Venus which have
been made up to this time are pure illu-
sions. Literary Digest.
Nerve Training.