Evening star., 1933-12-13
PLANET" All" STUDY
INDICATES NO LIFE
Investigations Are Reported
by Director of Mount
Wilson Observatory.
BY THOMAS r. HENRY.

The earth may be the sole abode of
life.
Details of investigations of the at
mospheres of other planets in the solar
system were presented here last night
by DR.. Walter S. Adams, director Of the
Mount Wilson Observatory of the
Carnegie Institution of Washington,
who is here for the annual scientific
exhibit which attends the meeting Of
the trustees on Friday.
Mount Wilson astronomers have
studied the "air" of the planets by
means of the spectroscope. Like the
earth, none of these bodies have any
light of their own The light which
comes from them is reflected sunlight.
This sunlight passes twice through the
atmosphere of the planets and. during
this progress, various wave lengths OF
it are absorbed by the different
elements present. Thus. by comparing
the spectrum Of planets light with
the spectrum of unaltered sunlight the
makeup Of the atmosphere through
which it has passed largely can be
determined.
Mars Has Little Oxygen.
The only other planets seriously pro-
are Mars and Venus, and the Mount
Wilson astronomers have concentrated
on their atmospheres. Both, DR.. Adams
said, turn out to be quite disappointing.
Mars air contains less than one-tenth
of l per cent of the free oxygen pres
ent in the atmosphere of the earth,
upon which life here depends. The red
color of the planet even suggests that
there Is none at all. Measurements with
the thermocouple show that the tenn
perature at the equator rises to about
40 degrees farenheit at noon, but the
extremely thin air offers little barrier
to the escape of this heat from the
planets surface and at night the tenn
perature must sink to at least 40.
The changes Of color In middle latitudes
melting of its polar ice caps during its
Spring season indicate that there may
be some vegetation. But, If so, DR..
Adams said, 1t must be Of a very prinli-
tive kind, since no plants on earth
would be able to Withstand such rapid
and extreme changes OF temperature.
The existence of any sort of animal life
is extremely unlikely because OF the
scarcity Of oxygen.
Specifically, DR.. Adams pointed out,
the earth's twin planet Venus, now
shining in the southwest as the. eve
ming star, might be considered almost
as fit an abode Of life as the earth It
SELF It is nearer the sun than the
earth and has considerably higher
mean temperature. 1t has very heavy
atmosphere. partly as a result OF which
its surface is continuously covered
with clouds below which the telescopes
cannot penetrate The exact length
of Venus day cannot be determined,
but it Is known that it is not so long
as the year. The temperatures above
the clouds on the dark and light sides
are about the same, showing that there
Is no such rapid shift as takes place
on Mars. Presumably it would be
good place for plant life of nature
similar to tropical vegetation on the
earth.
No Oxygen Is Found.
The difficulty comes with the Mount
Wilson studies of its air, which can be
known only from the sunlight reflected
from its clouds. There is no way to
know the composition close to the sur
face. They have found considerable
quantities Of carbon dioxide, which
plants breathe" but repeated efforts
have failed to show the slightest trace
of free oxygen. 1t may be there, be-
low the clouds. But If the condition
is anything like that on earth, consid-
cradle amounts could be detected above
the clouds. The presumption is strong
ly against any oxygen at all.
If this is true there can hardly be
any life, plant or animal. On the earth
the plants take in carbon dioxide gas
out Of the atmosphere and split it up,
freeing the oxygen for animal life to
breathe and incorporating the carbon
in their own structure. Probably the
earth itself would have no free oxygen
If 1t were not for the plants. II Venus
has none 1t is highly improbable that
there are any plants there-or II there
are they must live by an entirely diff
ferent mechanism than terrestrial
plants. And if there is no oxygen there
can be no animals. About the best that
can be assumed for Venus on the basis
of these findings is a very low order of
life comparable to unicellular life on
earth.
The other planets are hopeless, DR..
Adams said. Mercury, nearest to the
sun, has no atmosphere at all. It re-
fleets sunlight unchanged. It always
turns the same face to the sun. On
that side IL has a constant temperatllre