Evening star., 1940-11-02
Of Sturs, Men
And Atoms
Notebook Of Science Progress
In Laboratory, Field
And Study
By Thomas r. Henry.

By Thomas r. Henry.
About half billion years will be re-
quired for life comparable to that on
earth to evolve on the planet Venus.
At present about all space ship ex-
plorer who plunged through the thick
cloud blanket of the earths nearest
neighbor beyond the moon could hope
to find would be the lowliest forms of
plant life.
This is the conclusion of DR.. H.
Spencer Jones, astronomer royal Of Great
Britain, expounded in the annual report
of the Smithsonian Institution, issued
this week.
Specifically Venus would seem well
adapted as a home for living things. It
is about the size Of the earth. Approx
mately $4,000 900 miles closer to the sun,
its average temperature would be some
what higher. The heavy clouds which
hide its face from astronomers indicate
plenty Of moisture-although this Is
somewhat paradoxical in view of recent
findings.
But in the past few years several clues
have been obtained from which a more
rational, although still obscure, picture
can be obtained. First, spectra of the
reflected sunlight from Venus reveal
hardly trace Of free oxygen in its
atmosphere. There is, instead, heavy
concentration Of carbon dioxide. This
would preclude, at present, any posi-
bility of animal life.
The animal must have oxygen. Plants
breath carbon dioxide. In their physio-
logical processes they split up this gas,
retaining the carbon and releasing the
oxygen into the atmosphere. This, pre-
sumably, is the reason there is free oxy-
gen in the atmosphere Of the earth. This
gas is one Of the most reactive of ele-
ments. 1t will persist in a free state
thing, such as carbon, with which it can
form a chemical combination
VenuS then. would be ideal for plant
life. But If any great amount of vege-
tation existed there would be plenty of
oxygen. So, DR.. Jones points out, it may
be concluded that the plants are few and
primitive. Such a condition is similar
to that of the earth at the time of the
beginning of lfe-probably close to
billion years ago. The first animals
whose remains have been found in rocks
date back about half billion years, but
plant life must have had long period
of evolution before it could have pro-
vided enough oxygen for even the most
primitive breathing creatures.
Thus" says DR.. Jones, I'VE seem to
see in Venus a world where conditions
are somewhat similar to those that the
earth passed through millions of years
ago. Any life on Venus can be, at the
most, primitive plant life. 1t is possible
that life may be in process of gradual
development and that in millions of
years to come, when life on earth may
be nearing extinction, Venus may be the
home Of higher and higher types of life"
Conditions on Mars seem to be pre-
cisely the opposite. Mars is smaller
than the earth and, since it is farther
from the sun, much colder Its atmo-
sphere is very thin.
Thus far 1t has not been possible to
detect either oxygen or carbon dioxide
in the Marian atmosphere, although
there is indirect evidence for existence
of small amounts of the former. Water
vapor undoubtedly is present. Although
there are no seas, the polar caps must be
regions of ice and snow. The reddish
color of much of the surface Of Mars Is
probably due to the oxidation of from
bearing ores by atmospheric oxygen and
it is in marked contrast to the uniform
gray rocks of the moon where it is known
that no oxygen can exist.
THE extreme tenuity of the Martian
atmosphere" says DR.. Jones, "is respon-
sible for great diurnal variations in tenn
perature. A scanty atmosphere with very
little moisture in 1t does not have much
blanketing effect. Near noon at the
equatorial regions the temperature rises
to about so F., but in the afternoon as
the sun gets lower, 1t falls rapidly.
After sunset the cold becomes intense
and the minimum temperature at night
is about 1870 below zero. With such an
enormous daily range Of temperature.
the conditions for any form Of life must
be extremely trying. Whether animal
life can exist seems doubtful, although
it is impossible to assert that life may
not have evolved to meet those condi.
tions. In Mars we see Q world where
conditions probably resemble those that
will prevail on earth many millions Of
years hence, when most Of our present
atmosphere will have been lost. Mars
appears to be q planet Of spent, or nearly
spent, life.
Outside the suns planetary system, Dr..
Jones points out. the probabilities are
strongly weighted against the possibil-
ity Of life In any form similar to that
existing on earth. It may exist in other
galaxies.