Alexandria gazette. [volume] (Alexandria, D.C.) 1834-1974, 1882-10-23
Venus's Coming Transit.

The great astronomic event Of the yeal
will be the transit of Venus which occurs on
the 9th of next December. The Scientific
american says Of it:
Astronomers have been busy for years in
getting ready for the transit, for the whole
western world. where the sky is clear will
be in the sunlight during some portion of
the passage. The busy notes ofpreparation
are now being sounded in many Of the
American obscrvatories, where every aid
that science can command will be utilized
for the occasion, while European astrono-
mers have already formed their plans, re-
celvcd appropriations for the great expenses
to be incurred, and chosen stations which
are the best adapted for observations, as
we'll as those that are at extreme distances
from each other.
The phenomenon is not sublime and awe
inspiring, like total eclipse of the sun: nor
simply beautiful, like the conjunction oftwo
planets; nor magnificent, like the telescope
Saturn. The naked eye observer, looking
at the sun through a smoked glass, will see
tiny black spot passing ovcrhis face. The
telescope observer will sec black round
ball, as large as the full grown moon, max
ing its way across the great luminary The
phenomenon to the ordinary observer will
be only this and nothing more But thou
sands of scientific observers will eagerly
note, rs if life depended upon the accuracy,
the second when Venus touches the sun 5
edge, the moment when she is fully embark
ed upon his disk, the exact time of her pass
age, and the second when her retreating
edge touches the suns edge, as well as the
time when the last contact occurs and the
exhibition closes. There are two principal
reasons for the Importance attached to Il
transit of Venus. One is that it is consider
ed the best means for determining the sun S
distance: the other is that it is extremely
rare in its occurrence.
Venus and Mercury are the only planets
that can make transts across the SUM- for
their orbitsare within that of the earth. and
they are therefore called inferior or inner
planets. In every synodic revolution, or
when earth, planet and star come into line,
these planets must pass between us and the
sun, the point being known us inferior con-
junction. Venus accompishes this period
in five hundred and cighty-four days. But
her orbit, or path, is inclined to the ecliptic
or suns path, and, at inferior conjunction,
she ordinarily passes above or below the
sun and is invisible. When she is in inferior
conjunction, and also at one Of her nodes or
crossing points, as in Decembersh she passes di-
rcctly between us and the sun and makes Il
transit. The transits at the descending node
are in December, those at the ascending node
in June. The intervals between are eight
and two hundred and thirty-fivc years. The
transit of 1874 occurred eight years ago the
next transit after that of 1882 ut the same
node will be i'll 2ll7. The last transit at
the ascending node occurred in 1863: the
next will occur IN 2OOl.
When in 2004 the next transit of Venus
after the coming one takes place, no human
being who now trcads the earth will be alive
to see its passage. Nearly four generations
of men will have lived and died before the
brightest of the stars again passes between
lis and the sun when ut one Of her nodes
Observers will, therefore, witness an event
to be remembered for lifetime, and, for
this reason, Independent of its scientific i'm
portance, the phenomenon will be eagerly
anticipated. If astronomers can agree in
their calculations and make the transit a
means of accurately determining the suns
distance, great feat will be accomplished.
For the suns distance from the earth is the
unit or yard stick for measuring celestial
distances outside the solar system, and On
its accuracy the whole celestial structure
depends.