Evening star., 1950-10-16
Deadly Rain From Stors
Falls on Earth S Roof
Experts Soy 1t Moy Set Limit
For Altitude Man Cun Reuch
By Thomas r. Henry


A deadly rain from the stars falls on
the roof of the world.
It may set the limit for the altitude
man can reach.
This has been affirmed by DR.. Her
mann j. Schaefer of the Navy School
Of Aviation Medicine at Pensacola and
is q factor not hitherto considered in
speculations regarding space flight.
The invisible rain becomes dangerous
above about 10000 feet over the earth's
surface, and presumably the danger in
creaSes for higher attitudes, according
to DR.. Schaefer's calculations. Its ex-
iStence has been known only during
the past two or three years and no at
tention has been given to it's probable
physical effects.
This precipitation is the rain of pri-
mary coSmic rays-far different from
the comparatively weak cosmic ray sec
ondaries which hit the earth, some of
which are sufficiently powerful to pene-
trate thick shields of lead. Everybody
is being hit by these secondary rays all
the time and so far as is known they
do no damage, except for possible bad
effect on heredity.
Primary Rays Something Else.
The primary rays are something else
again. It has been shown by rocket
flight observations and various calcu-
lations that they consist of two kinds
OF particles. The majority probably
are protons. Effects of proton radiation
on the human body still are obscure.
1t Is one Of the dangers from an atomic
bomb.
But a considerable proportion of the
primary rays are much heavier par
fiNlnS-fha nY1ff Lot @f
atoms, some as heavy as iron The
forces with which they are propelled
are incredibly fantastic, ranging from
20 billion to 100 quadrillion electron
volts. CThis last figure is somewhat
speculative and may be cut down-or
raised-in the future) The greatest
energy with which particles ever have
been propelled on earth is about 400
million electron volts-the energy built
up in the largest cyclotron.
What would happen to a man hit by
lot OF these high-energy heavy par
tlcleS over a prolonged period? This
is all matter of conjecture. DR.. Schaefer
admits, and there is no possibility Of
experimental tests
A fair comparison, however, may be
made with alpha particles, the nuclei
Of helium atoms, such as are emitted
by radium and which are used in cancer
therapy. These are about the closest
objects known on the surface of the
earth to the upper-air projectiles
We live in the midst of these alpha
particles. The body is full of them
1t has been calculated that about one
cell in everybody's body is hit by one
of them once minute. Once one Of
them Is emitted by some alpha-pro-
in, ~,
air we breathe, it moves about 100 mil
lionths of a centimeter, through ap-
proximately 10 cells of the body. Along
its path it produces ionizations-that is,
1t breaks up the atoms. This is the
way it produces damage.
Could Disintegrate Cells.
Now, it has long been accepted that
the normal alpha activity in the human
body is essentially harmless 1t would
have to be increased at least ten-fold
to cause much real damage.
But single one of the heavy par
ticleS of the star rain would penetrate
nearly 10 centimeters, or more than
three inches. 1t would strike at least
10000 cells. Due to its far greater
energy, it could be expected to pro-
duce much greater ionization It is
quite likely that it completely would
disintegrate most of these cells.
DR.. Schaefer calculates that an amount
OF heavy particle radiation equivalent
to the normal alpha particle dosage
received by every human being every
minute would cause at least Is times
as much damage-far above the estab-
lished danger limit. Actually the dos
age at 10000 to 10000 feet would be
much greater
Up to 10000 feet, the report con-
cludes. there is little danger-except
possibly to the germ cells affecting he
redlty.
Above $4,000 feet it begins to get
acute. The bombardment would be in
visible and painless. A space traveller
would be unaware that anything was
happening to him. Perhaps he would
require at least 100 hours exposure be-
fore fatal or badly disabling effects
were noticeable
There could be no possible shield
against this radiation.