Evening star. [volume] (Washington, D.C.) 1854-1972, 1910-01-15
PEOPLE IN THE STARS
POSSIBILITY OF INTELLIGENCE
ON MARS AND VENUS.
Two "Solar Planets" May Have Sen.
tient Beings Upon Them-Re-
semblance to the Earth.
From Popular Astronomy.

The study of the possibility of reason
ing existence on other worlds is of peren-
NAL interest, but intelligent speculation
on the subject must be confined to the
solar system, on account Of the inn
mensity of the void existing between that
system and any other. Study OF the
habitability of the eight known major
planets leads at once to the elimination
Of six of them. The habtability of the
earth is a matter Of constant observation;
that Of Mercury may be negatived on ac-
count OF extreme solar proximity and
lack OF atmosphere, and Of the four outer
planets, Jupiter. Saturn, Uranus and
Neptune, their remoteneSs from the CEN
trail energy. as we'll as other conditions
not discussed herein, may well remove
them from the field Of consideration. OBJ
servation upon the four has yielded mega
tive, rather than positive. results in
numerous ways, 50 that with the excep-
ton of Jupiter it cannot he certainly
stated that any extensive parts OF their
actual surfaces have been seen. so far Is
this true that the times of rotation OF
Uranus and Neptune remain to be deter
mined although some recent observations
have assigned to their rotation periods
1O.1 hours and 1885 hours. respectively.
The two solar satellites. Venus and
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with the exception OF the moon and the
minor planet Eros on an occasional OPP
position. are left for discussion: and In
this 1T Is intended that the assumption OF
the possibility of life in some form shall
be granted, having only in mind the ques-
ton as to the adaptabillty Of either or
both of the planets to the support Of that
form Of life that Is called intelligent or
reasoning. though. of course, not neces-
sarily, in physical aspect, resembling
man.
Size of Venus.
In diameter Venus is about 100 miles
less than the earth, which is reckoned at
1926 miles This resemblance is close,
strikingly SO; there Is no member OF the
solar system that in this respect at all
approaches these two. according to ter
restrial standards. The outer major plan
cts are giant globes. measuring from four
to ten times the diameter of the earth.
Mercury is about 1900 miles through, and
the moon quarter of the earth axial
measurement. Mars has trifle more
than half the apparent measure Of the
earth and Venus. or 4,21O miles.
The identity in size between the earth
and Venus is followed by another SINH
larity of equal Importance, in the study
of habitablity from the human stand
point: namely, the correspondence In
density between the two, which is prac-
locally the same. On the other hand. the
density of Mars appears to be about
seven-tenths that OF the earth. Likewise
the masses of the planets are as for the
earth, O.S for Venus and about oil for
Mars, hence would follow a wide dis
parity between the gravitational force
exerted on the surfaces of the pair, and
that on the outer planet. But this dis
parity is modified, for the fact that gray
ity varies with the inverse square of the
distance. acts as d counterpoise in the
case of Mars for his inferior mass. TAX
ing the radial measurements, objects
upon the surface of Mars lie only about
2.OOO miles from his center of attraction.
whereas that distance is about doubled
for Venus and the earth. The force of
gravity at the earth's surface reckoned
as 1 is for Venus nearly the same and for
Mars about OBS; SO that a man weighing
80 pounds, transported to Mars would
find his weight reduced to about fifty
seven pounds.