Evening star., 1952-05-28
All Rure Gas Held Due
To Radioactive Mineral
Moy Also Be Responsible
For Heut in Eurth's Crust
By Thomos R. Henry

A radioactive mineral. Potassium 40,
may have created all the rare gas, argon.
in the earth's atmosphere.
It also may be responsible for con-
siderable part Of the heat coming up
ward through the earth's crust.
This thesis is maintained by DR..
Francis Birch Of Harvard in q report to
the Journal Of Geophysical Research.
just published.
Argon constitutes about 1.3 per cent
Of the earths atmosphere, a total Of
about so trillion tons. It is one of the
mobile cases." like neon and krypton,
which also are found In the atmosphere.
1t has the faculty Of reacting with
nothing.
It is approximately 1000 times more
abundant, however, than neon. Yet out
side the earth's atmosphere-in the stars
and presumably in the universe as a
whole-neon Is far more abundant than
argon. It is more than 1000 times as
abundant as krypton. There are no re-
liable figures on the cosmic abundance
Of the latter gas.
But the fact that the earth's atmos-
phere is richer in argon, although
nature as whole is richer in the other
gases, suggests strongly a terrestrial
origin for this peculiar substance. One
Of the products into which radioactive
potassium Is transmitted, 1t now is
known. is argon. Calculating the half
life of potassium at the now-accepted
figure. somewhat over a billion years.
DR.. Birch finds that the amount changed
into argon would somewhat more than
account for the, amount of this gas in
the atmosphere.
Potassium the Source of Arg0n.
There remains, however, q major diffi-
Guilty. The gas was created in the in
terror OF the earth's crust. It is necessary
to assume that the greater part now in
the atmosphere was created in the first
billion years Of the earth's existence,
when presumably the crust was like a
boiling liquid. This would have per-
mitted the escape Of gases. The next
billion or so years was probably period
OF considerable volcanic activity. which
would have thrown considerably more
OF the gas into the atmosphere.
Since then. however, it is not prob
able that any of the gas has esce. =
although it still is being formed at the
same rate.
Something faster than any wind
moves with the northern lights.
This mysterious something must be
assumed, although it cannot be de-
Scribed, to explain the curious phenom-
enon of "auroral propagation" which
surprises radio amateurs at times when
there are exceptional displays Of the
aurora borealis..
The latest attempt to explain the phe-
nomenon Is that of r. X. Moore Of
Cornell in the latest Journal Of Geo.
physical Research issued at the Carnegie
Institution here.
At freQuencieS between % and 148
megacycles radio propagation is possible
to distances seldom achieved at other
times. At the same time there is very
high fading rate so that voice Is rem
dered unintelligible.
Aurora in Daylight Reported.
Best results are obtained when direc-
tional antennas are pointed north to-
wards the aurora. The phenomenon,
however, Is not restricted to hours Of
visible aurora, for it is frequently re-
ported during daylight hours, immedi-
ately preceding dusk and Immediately
following dawn.
The work at Cornell was carried out
under a contract with the Army Signal
Corps, to whom anything affecting COM
munication in the polar regions is Of
great Importance.
The apparent cause. DR.. Moore says.
is scattering of the signals from some
thing either associated with or accom-
panying the northern lights (which is
moving at a speed greater than that
known for ionospheric winds" It is
known that there are winds in the iono-
sphere. the rejecting electric roof
region Of the earth, of speeds greater
than 100 miles an hour. The northern
lights displays occur at far greater
heights than the ionosphere.