The morning news. [volume] (Savannah, Ga.) 1887-1900, 1891-01-18

given by astronomers in recent years. It's
extraordinary brilliancy has caused il nat
urally % be selected for the first expert
menis aiming ct an advance step IN sidereai
astronomy, and the items OF information
that have been gathered with respect to this
star may be cited to illustrate ths present
state OF our knowledge regarding these
almost infinitely remote bodies.
UNIT OF STAR DISTANCES.
Although not the nearest Of the fixed
stars, Sirius is among the nearest. Its dis
lance from US now is commonly put at about
1000 times that Of the sun. Let US take
a moment 70 consider what this means. Or
binary units of measurement fail ms in an
emergency like this; a new unit has been
adopted for measuring star distances. viz:
the distance travelled by light in one second
OF time-lS6, 600 Males. To reach US from
the sun light requires q little over eight
minutes; it flashes across the space inter
ventng between Us and the moon In about
seconds; to reach US from Sirius, assum-
Ing that the distance given above is correct,
u requires nearly ten years. That is, when
we look upon Sirius tonight we see it, not
as It Is now, but as it was ten years ago.
1t has been estimated that the light OF
sirius Is equal 20 taat OF seventy suns
placed side by side. IL is intrinsic brill
fancy is the Same as thai Of the sun, 1t may
easily be calculated that, its diameter Is
rather more than eight times that Of the
sun. There nre, however, reasons for think
ing that Sirius is really hotter and brighter
than our luminary, in which case the esti-
mate OF its size mast be correspondingly
diminished,
THE MOTION OF SIRIUS.
Within the past few years the spectre
scope has been applied TO perform the as
tonishing feat of Determining the rate Of
stars motion In direction toward or away
from the earth. Sirius is the first star to
which the spectroscope was turned for tais
purpose. but DR.. Higgins, who confidently
announced that the star was receding from
us at the rate of twenty-nins miles a second.
Other observers have confirmed the conciu-
sion of this distinguished spectroscopst as
to the fact that the star is moving along the
line OF sight, but its motion bas been found
TO vary both in its rate and in its direction
In manner thus far unexplained.
Mercury will be an evening" star during
the first half of the month, and during the
second half morning star, but too near she
sun 20 De visible, Venus is now morning
star. It's greatest brilliancY was on the Sth
of the month, at which time, seen through a
telescope, 10 presented the crescent phase of
the waning moon. The Complies Rendues
for October II, 1890, contains an interesting
illustrated note by M. Perrotin, on "Ob-
Observatory at Nice" made with view of
determining the period Of the planets rota>
ton oD its axis. NJ. Perrotin confirms the
conclusion recently announced by NJ. Schia-
pareli OF Milan, that Venus turns on its
axis in very nearly, if not exactly, the same
time that it lakes to perform its revolutions
IL Its orbtt-viz., about 225 days.
ETERNAL DAY AND ETERNAL NIGHT.
That is VenuR alwavS kaanq fha CANA sida
turned toward the sun, just as the moon
does toward the earth, and just as Mercury
according to NJ. Schiapparelli, does toward
the sun. On one side of tais plant there is
therefore, a continuous day and ON the other
side eternal night. Mars is still struggling
to keep pace with the earth; but, although
now long way in advance of Jupiter, he
has lest ground very perceptibly in the
past month, and now sets at about s o'clock.
Jupiter has practically closed his present
season. He is visible but for a sort time
after sunset