The Opelousas journal. [volume] (Opelousas, La.) 1868-1878, 1877-09-15
TIE OPPOSITION OF MARs.

VI 4AEs
! are DOW waiting wit
great interest for a phenomenon whic
: IS to occur in a few weeks, and is to b
: observed with the utmost care an
! assiduity, aud with all the appliances a
the disposal OF science. On September
, the planet Mars will be lin opposition
that is, be will be at that point of tn
sky which Is just opposite the sun, s.
that ne will rise at sunset, and come t,
the meridian at midnight Since boil
the planet and earth sweep in orbit
around TIE it follows also that at tina
time they make theif nearest approach
to each ether, and the planet is ther
most faTorably situated for observation
and examination. In the early autumn
Mars will be by far the most conspicuous
object in the eastern sky, blazing with a
red fire hardly infe.io to the brightness
of Venus, which by that time will begin
to adorn the western twilight, and quite
o~utshining Jupiter. Saturn, close by
Mars, will seem comparatively of no
account.
Oppcsitions of Mars are not specially
rare. They occur once in about two
years and fifty days, and if the orbits of
this planet am the earth were perfect
circles the circumstances Of all opposi-
tlons would be essentially alike, and no
peculiar interest would attach to one
rather than another. But this is by no
means the case; the orbits are not quite
circular. The earth, about the first of
July, is nearly 5000, 900 miles farther
from the sun than at new years; and in
the case of Mars the difference between
its greatest and least distance from the
sun Is larger yet, amounting to almost
$4,000, 900 miles. The average distance
between Mars and the earth at the mo-
ment of opposition is about 40, 900, 900
miles if, however, the opposition hap.
pens when the planet is as far from the
sun as possible, and the earth as near the
sun as it can be, they will be separated
by a space Of 81 1000, 900 miles; and if, on
the contrary, the event occurs when the
conditions are reversed, the distance
between them will be only thirty four
million, and the opportunity for obser-
'ation will be exceptionally favorable.
These close oppositious are rare, the
notions of the planet and the earth
icing so related that they recur only at
intervals Of seVenty.nine years, though
ONE of the intermediate oppositions, {
eParated by periods of fifteen and E V
nteen years, are not very greatly infe- }
ior. The opposition of next September c
ill be one Of the best possible, both !
arth and planet being in the most fav- i
rable positions, and the distance be- t
ween them less than at any time since t
ne summer of 1898. The observations il
be made are of two claSses-one in a
'nded to determine the distance, posi-. b
on and motions of the planet; the Il
her relating to its magnitude, form, W
surface-markings and physical a
-
Bearing in mind that the proportions nj
the planetary system are easily ascer- te
ined and now very accurately known, C
is of course evident that the precise tC
in miles of any single dis tt
nee between any two planets will fix 81
e dimensions of the whole system, M
80 to speak, put a scale of miles Ie
our chart of the universe. Obser- or
tions of the opposition of Mars are II
erefore available for the same purpose tn
those OF a transit of Venus, and some he
tronomers consider them capable of til
wing a result hardly, if at all, inferior
certainty and precision. It is for this no
Ison, chiefly, that the phenomenon is 50
'ked forward to with SO much interest. ol.
. Y. Times. at