Evening star., 1937-02-27
STARS, MEN AND ATOMS
Notebook of Science Progress in Field,
Laboratory and Study.
BY THOMAS r. HENRY.

The outer atmosphere of the planet
now is getting an exceptionally heavy
bombardment of corpuscles from the sun.
fired into space with speeds approaching
that of light.
The sunspots, now increasing rapidly
in number and tempestuouSneSS as they
approach their 11-year maximum, serve
as the suns heavy artillery for this
constant shelling Of the region nearly
200 miles above the earth's surface.
Some of the effects are described by
DR.. L. v. Berkner of the department of
terrestrial magnetism of the Carnegie
Institution of Washington.
Under the action Of radiations coming
from the sun the atoms and molecules
of the atmosphere at these heights be-
come electrically charged. or "ionized,"
enabling the region to conduct electric
currents and to reflect back to the earth
radio waves which otherwise would
escape into outer space. BY sending
short pulses of radio waves of various
frequencies into this region and observ-
ing the time required for their echoes to
return to earth-an interval of few
n-thousandths of a second-it is pos
sible to determine the exact number of
charged particles at the various heights.
Around midday in the Summer at
Washington three well-defined regions of
electrification now are known to exist.
The lowest of these is at height of
about IS miles. where the number of
electrified particles or ions is about
$500 900 per cubic inch This is called
the E-region. A second region Is found
1f ka,, In, vytnfpI
the ion density reaches about 100000
of 100 miles, has an ion density of 16,-
900, 900 per cubic inch or more.
The lower two layers are ionized by
the ultra violet light from the sun. There
is much evidence that the highest region
is ionized by corpuscles projected from
the sun and bombarding the outer at
moSphere. The heights and ion intensi-
ties Of these layers change from day to
day and hour to hour. In June. when
the sun reaches its greatest height in
the sky, at washington the upper two
layers Of the ionized region are dis
tinctly separated, while in December,
when the sun does not climb so high,
they are merged. The reverse situation
obtains at the Carnegie Institution sta
ton in Western Australia. There the
two regions are merged in June. the
Southern Hemisphere's Winter.
Changes in the lower two regions which
are ionized by ultraviolet light from the
sun reveal clearly the effect Of the in
creased intensity of sunlight from season
to season in each hemisphere, the more
intense the sunlight the greater the ion
densities. The ultraviolet light and
corpuscular radiation which create this
electrical condition in the outer atmos-
phere are completely absorbed there. 1t
was known from mathematical calcula-
ton that such radiations must be pres
ent, but because they were not visible
on the earth little was known about
them. Now that their effect on the
outer atmosphere can be measured,
knowledge of the suns radiation is
greatly enhanced.
1t long has been known that when
sunspot activity was high, fluctuations
in the earth'S magnetism were more fire.
quent and intense. The manner in
which these changes affect the earth's
magnetism now Is becoming clear. One
of the most striking changes which has
been revealed Is an increase in the ion
density Of all the regions during the
past two years. This change amounts to
about so per cent in the two lower re-
gions and to more than 200 per cent IN
the highest region. It is attributed to
the increase In the number Of sunspots.
Tha ehanae, DR.. BerkneI points out,