The Minnesota fiery cross. (St. Paul, Minn.) 1924-19??, 1924-05-30

one of its closest approaches to the
earth within the present century.
The two planets will be separated by
about 35,O00,OO0 miles, which Is, cos
mically speaking, a mere tribe.
Every two years and two months
Mars is in Opposition" to the sun
that is to say, the sun, the earth, and
Mars are in straight line, with the
earth in the center. The planet then
rises at sunset, crosses the meridian
at midnight, and sets at sunrise; and
fer some months before and after
these oppositions the planet Is
prominent object in the night sky
and Is carefully watched by astron-
omers located in various parts OF the
earth.
So far as distance Is concerned,
however, all oppositions OF Mars are
not equally favorable. As we all
know, the Earth's orbit Is not Q cir
Gle, but an ellipse, and our world Is,
As a matter Of fact, three million
miles nearer to the sun at midwinter
than at midsummer-a fact which, by
the way, mitigates the heat Of our
northern summers and the cold OF
our northern winters. The orbit Of
Mars Is considerably more elliptical
than ours, and its distance from the
sun has a greater range Of variation.
Now it is evident that the earth and
Mars come nearest when Mars Is AZ
a point of it's orbit near to and the
earth at point far from the sun. On
the whole, an opposition of Mars is
favorable, so far as distance is con-.
cerned, if it occurs in July or August,
and unfavorable if it falls in January
or February. There are, however, so
far as we in the nothern hemisphere
are concerned, other factors to be
considered. When Mars comes to OPP
position in late summer it is travers-
ing the lower zodiacal consultations
and does not rise high above the hori-
ION, while in late winter it rides high
in the sky and is actually more cas-
ily picked up by the casual star-gaz-
er than on the occasion Of the favor
able oppositions of late summer.
A Sunny world
At the same time, SO far as the
earth as a whole is concerned, these
near approaches are very favorable,
and the astronomers, farther south
will have the opportunity of seeing
Mars at its closest when the disc is
at its maximum apparent size.
Mars is not actually our nearest
planetary neighbor in space, % Venus
on occasion comes as close as 26,000,-
900 miles. But on these occasions the
dark side of Venus lis turned towards
., and we can see nothing; while
Mars, at closest approach, is fully IL
Illuminated As a consequence we
know much more about Mars than
about Venus. Concerning the latter
planet, indeed, assured knowledge is
very slender.
Mars is considerably smaller than
the earth. Its diameter is about A.
S60 miles, and its volume less than
two-tenths of that of the earth. Like
the earth, Mars is enveloped in an
atmosphere of appreciable extent and
density, but this atmosphere is much
clearer and thinner than ours. Com
pared to our cloud-laden planet, Mars
may well be described as a world OF
blue skies and bright sunshine. And
this despite the fact that at dis
lance of about 100000 miles far
Their from the sun than the earth, IT
receives considerably less light and
heat than we do.
The Marian surface has been care
fully scrutinized and charted for
about 200 years The most promi-
nent features of the disc are the two
round white spots at the north and
south poles, which were detected as
long ago as 1719. These spots are OBJ
served to increase and decrease in &C
cordance with the marian seasons.
Thus in winter in the northern henri
sphere the cap is very extensive. As
the spring comes the cap shrinks, and
by midsummer ii is a tiny white
point. Indeed, on more than one oc-
casion it has been observed to disap-
near altogether. Quite obviously
these polar caps are the Arctic and
Antarctic snowfields of our neighbor
world. As the caps melt they are
usually seen surrounding them broad
blue belts. These are evidently open
polar seas, formed by the melting OF
the SHOWS. As a matter of fact these
temporary bodies are the only seas
on the Marian surface.
The Canals
For on Mars the apostolic vision is
realized There is no more sea-" The
blue-green areas which the earlier
observers such as Herschel, Nader,
Dawes and Proctor believed 60 be
oceans are now definitely known to
be vegetal in nature, for they change
their color and their boundaries shift
as the seasons progress. The reddish
ochre portions which form the great
or part of the planets area are sim
ply observation-disclosures to barren re-
gions like the Sahara on our own
planet. The monotony of the deserts,
however, is relieved by the remark
able network of lines known as the
canal system. The more prominent
Of these canals were discovered by
the great Italian astronomer Schia-
parelli at the favorable opposition of
1877, and on subsequent occasions he
discovered many more. Even greater
numbers have been detected by Flam-
marion. Lowell. Pickering and other
astronomers. Still more remarkable
than the canals themselves are the
"oases," the dark spots at the june
tions of two or more Of the canals.
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