Evening star., 1940-09-17
Of Stors, Men
And Atoms
Notebook Of Science Progress
In Field, Laboratory
And Study

j" TIeios IoOOIutOIy
And Study
By Thomas r. Henry.
The moon is the motor Of a titanic
electricity generator. with the earth,
wound with coils OF sun wire, as q
magnet.
This is the finding Of DR.. ]. Bartels,
professor of geophysics at the University
Of Berlin who for the past year has been
a guest scientist at the Carnegie Insti-
tuition Of Washington. Member OF a
German delegation which came here
last September, DR.. Bartels was unable
to return because Of the outbreak Of war
and has spent the year working out the
details Of an hitherto unknown phenom-
enon of nature which may have far
reaching practical results.
The earth, Dr. Bartels explained, is q
giant magnet. A part of the sunshine
falling on its high atmosphere is in the
extremely short, invisible ultraviolet
light range. These short waves knock
electrons of the atoms they hit In the
rarified air so miles or more above the
earth's surface. The result Is to make
these atoms electrically unstable and to
generate minute currents Of electricity.
These might be considered as the wires
wrapped around the coil. Then the
moon, through its tidal action. which
Is the same on the air as on the sea,
pulls these wires up and down through
hn OIL IL Wit
magnetic force of the earth itself, as re-
flected by the compass needle. Also the
current in the upper atmosphere is in
creased. A current Of from 10000 to
200 900 amperes is produced.
Curiously enough, the moon can act
as a motor only in the daytime, when it
is invisible. At night the upper atmos-
phere is not electrified because there is
no radiation from the sun passing
through it.
The present practical importance OF
the phenomenon, DR.. Bartels explained,
is as an almost perfect instrument for
measuring variations in the radiation
OF the sun, upon which all life on earth
depends, in those wave lengths which are
absorbed long before they reach the
highest mountain peaks where they
could be measured with instruments.
1t has long been understood, DR.. Bar
tells said, that there are daily variations
in the earth's magnetic field due to cleo
trical changes in the upper atmosphere
caused by the daily tides. There were,
however, three factors involved-the
moon, the tidal action OF the sun and
the heating effect Of the sun-which
caused atmospheric strata to rise and
fall. 1t has been impossible to separate
these three.
This year. however, DR.. Bartels and
DR.. H. F. Johnston of the Carnegie staff
found exactly what they wanted in the
daily magnetism records kept by the
institutions observatory at Huancayo,
Peru. This station is ideally situated
exactly on the magnetic equator but
several degrees south Of the geographical
equator. Here the variations of mag
netism with the various phases of the
moon could be measured exactly. They
are the same the world over.
Consequently, says DR.. BartelS. 1t is
now possible to separate completely the
moon effects from the various sun ef-
fects. When this has been done. exact
determinations can be made of the eff
fects Of changes on the sun in electrify-
ing the atmosphere and this is a direct
measure Of these changes themselves.
The sun Is variable star. Its heat and
light fuctuate from day to day-sup-
posedly in regular cycles. These iuctu-
ations, in turn, are supposed to have
some effect on the earth's weather and
have been alleged to affect such far
removed fields as the stock market and
crop prices
A notable example cited by Dr. Bartels
is the sunspot cycle. These are great
cyclones in the blazing atmosphere Of
the sun. The magnetic variations, with
the moon effects eliminated, measure
precisely the increases in the shorter
wave lengths Of radiation as the sun
goes from sunspot minimum to a SUM-
spot maximum. They show, DR.. Bartels
says, that there is about q twofold in.
crease. Hitherto, the only way to de-
termine changes in solar radiation was
by means Of instruments on high noun
tain tops or carried aloft in balloons
which could measure only the light, heat
and q little Of the invisible ultra
violet which came through the first
100 miles or so Of the atmosphere Such
variations always have been found to be
very small-almost within the limits of
experimental errors.
I'VE have at last found a way of
measuring what goes on on the face of
the sum-" DR.. Bartels said IT do not
know Of course, whether there are any
direct effects Of such solar changes on
human beings. Many seem to think
there are such effects. I worked for a
long time with a man in Germany who
thought suicides were tied up with the
sun, but the investigation, as might have
been expected. came to nothing
Before, talk Of this kind has been
just idle speculation. Now we have the
first .essential-an objective means Of
knowing what goes on on the sun. Once
this has been determined comparisons
can be made with earthly events"