The evening times., 1900-06-18
NEW FACTS ABOUT VENUS.
Day end Night ON the Beautiful
EvenEna Star.

Evening Star.
An accomplished astronomer has ju-t
made a discovery in the heavens whi>h
merits our close attention. for it amplifes
human knowledge CT the condition Of an in
teFesting neighboriEg world. That neigh
boring world is the beautiful planet Venus,
and that the discovery should have ben
made just now viii occasion no surprise
to anyone who has watched the brilliant
orb which has for weeks been ad5rnirg
the evening sky.
Venus pcsseses a special and particular
interest from the circumstances that il IS
a globe which in many respects has start
ling resemblance to the earth. To b.
gin with, the beautiful evening stEr is
almost exactly the same size as this g,oSe.
The number Of miles trayersed in mlldr
voyage arouht the equator Of the earth
would be almost icertical with the nunn-
Der Of miles which would make an equa-
torial girdle for Venus. Nor does TIE Ie-
semblance between the earth and the
planet consist merely in their equal size.
The two globes have practically the same
weight
II there were a pair CT weighing sclies
so mighty that Venus could b. put in,o
one pan and the earth into the other no
great difference would be perceived le
tween the weights Of the two ceiezti
orbs- Two billiard balls which had 10
greater proportional difference in size and
weight than the earth and Venus would
be practically SndistiuguiSSabie- The re-
semblance between these twin planets has.
however, been carried much further BY
TIE Interesting discovery which has just
been announced to astronomers.
To . planet which may be the abode OF
life oae OF the most important conditions
VIII - the Succession Of day and night
Whenever the question as to the rssem-
blance Of another world 10 the earth Is
raised IL is natural 10 consider how far the
Inhabitants Of such a world. II inhabitants
there be, resemble the people OF the earth
in the enjoyment OF the alterations of a
day when the sun is in the skies with
night when the sun is below the horizon
The change from day TO night, the change
from night 10 day are. OF course. conse-
quences Of the rotation OF the planet on
its axis. II has long been desired to learn
how far the period which the planet re-
quires 10 complete each turn may agree or
disagree with the time required by the
earth for a Ike movement. To put the
mater more definitely. Il may be enqu!red
how far the period required by Venus 10
rotate on its axis corresponds with tnat
period CT tWeuJy-four hours. or. more ac-
eurateiy. % hours and Sc minutes. which
expresses the tine taken by the earth 20
complete one revolution about its axis. The
determination Of the length OF the day and
the length OF the night 20 which the in
habitEnts Of Mars must accommodate their
dcnestic arran geIueuts has never admitted
OF much doubt Indeed the length of the
day on Mars TO a single second OF time IS
known. This determination has been made
r-frr -. Nawz
are cIesr enough TO be precisely identified.
After the lapse Of years, or after the lapse
0f even csnturis. those marks are Still 20
be seen. without any doubt Whatever. n
each revolution OF the planet But fer thu
study Of length Of day and the length Of
night on Venus the face OF the beautiful
eTening star offers no such facility. This
globe has no well-ularked features; there
are no definite spots to suily the brilliant
mantle of sunbeams Characteristic or the
evening star
One very eminent astronomer thought
that the day in Venus must be enormously
loug-must. in fact. last for about fifteen
weeks while the night which succeeded
il had 10 last for fifteen weeks more This
discrepancy showed that the marks on the
planets globe were not sufficiently def
mite to solve the problem. Such marks as
could be seen with more or less distinct
ness were most probably merely clouds in
the atmosphere Of the planet and coESe-
Quently had no permanence- Some other
method OF solving the problem not exposed
20 such difficulties was clearly necessary
\ totally new method OF attacking the
question has been applied 10 Venus during
its present apparition by the astronomer
Belopolski He has adopted a totally diff
feTeEt principle. As the planet turns
round one edge comes toward US and the
other edge goes from Us II the period be
the short one. like our own day. then the
edge which is advancing toward US VIII
move more rapidly than Il would be NOV
ing If the period were 70 be expressed by
months. II Is easy 70 see that by deter
mining the rate al which the advancing
edge Is coming toward Us It is possible 20
calculate what the duration OF the whole
rotation must be.
A beautiful new process permits this to
be done. BeiopOlski found that the edge CT
the planet coming toward the earth is
moving faster than IT would be il the long
period Of rptatiOn were adopted, and be
had therefore determined that the short
period must be accepted Thus a most diff
ilcUit question has been set at rest To
the other analogiss between the earth and
its twin globe Venus must low be added
that the day and night for any inhabitant
on that world succeed each other in much
the same fashion as day and night succeed
each other on this earth