Evening star., 1940-05-12
This month our sister
planet is 50 close you
can see her at MONDAY

PAVE you ever observed the eve
ming star at noon? 1t is really
d quite easy these days, for
yenus is again playing her consplcu-
,us role in the evening sky. 1t IS
rowing brighter every night, and on
Nay 20 it will attain its maximum
luminosity - nearly sixty times the
,rilliancy OF the brightest fixed star in
he sky. If you haven't noticed it, just
ook westward at sunset. You can't
Mss it, for it shines conspicuously
ong before the sky darkens.
The easiest way to locate the planet
it noon is to begin the evening before.
FACE west at sunset and extend your
arms, pointing the right hand at the
iun and the left hand at Venus Next
lay at noon, face south and extend
Pour arms so that your hands are
sbout the same distance apart as they
we're the night before. Then. with your
light hand covering the sun. sweep
he left hand through the sky. keeping
he same angle between your arms.
Somewhere near the path your left
aand traces. Venus should appear.
Venus is our sister planet in several
Sespects. 1t is our nearest neighbor on
he sunward side. and when it passes
between the sun and the earth it ap-
breaches within 100000 miles Of
sls - closer than any other planet can
some. Moreover, Venus is almost as
big as the earth, whereas all the other
planets are either much larger or much
mailer.
! Venus exhibits all the phases of the
noon. and at present, when viewed
With a telescope, it appears as cres-
:ent. At full-moon phase the planet is
nconspicuous because it lies l6O,-
700, 600 miles away. When nearest to
IS it is invisible because only its dark
side is turned toward US. Its apparent
brightness is thus determined by two
variable factors - distance and phase.
These factors tend to Offset each
,ther. and. oddly enough, we receive
he most light from the planet not
when it is full, but when it is in the
:rescent phase.
Nsnv,'s Mystery
In THE past, several keen-eyed OBJ
servers have recorded few vague,
lark areas on their drawings of the
planet Most astronomers were unable
to see the spots even under the most
favorable conditions, and their origin
was generally ascribed to magma
ton. The mystery remained unsolved
until a few years ago when Frank E.
Ross secured a remarkable series of
color photographs at the Mount Will
son Observatory. On his ultraviolet
photographs. indefinite dark areas
appeared. Although most human eyes
are insensitive to ultraviolet light,
there are occasional exceptions. Evil
IDENTIFY those astronomers whose visual
observations were questioned, ac-
tually saw what their colleagues could
not detect.
No one has ever observed the sur
face of Venus. The planet is enveloped
in a dense, perpetually cloudy atmos-
phere that defies penetration. Re-
Gently. Earl c. Slipher. of the Lowell
Observatory. has engaged in an ex-
tensive study of that atmosphere. His
photographs. totaling more than 500,
show considerable and varied activity
the cloud formations. Slipher
believes that the entire atmosphere is
very dusty. condition that renders
it virtually Opaque. From study of
the rapid changes of the dark areas,
he concludes that winds blowing a
hundred miles per hour may be COM
mon.
No one knows how long the day
lasts on Venus. Astronomers usually
tho dow ~, orothor uyor1l h1y