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The 1958-59
International Geophysical Year was an unprecedented eighteen-month global
scientific initiative involving 30,000 participants from 66 nations who invested
up to 1.5 billion dollars to study Earth's interior, oceans, and atmosphere.
Utilizing military rockets and emerging satellite technology, researchers
achieved major breakthroughs, most notably Dr. James Van Allen's discovery of
the radiation belts surrounding Earth and enhanced understanding of ionospheric
radio propagation, solar flares, and geomagnetism. While the project aimed to
improve communications and weather forecasting, it also served as an optimistic
exercise in international cooperation during the Cold War. From a contemporary
perspective, the IGY is recognized as the foundational era of modern space
exploration and planetary science. The data collected validated early satellite
capabilities and established the parameters for human spaceflight, permanently
transforming our grasp of the near-earth space environment and confirming the
utility of space-based observation nodes that remain essential to global
communications today.
International Geophysical Year (IGY) - An 18 Month Report
The recently concluded "International Geophysical Year" was an
outstanding example of the tremendous results which can be achieved when nations
band together to tackle a common problem. The data obtained during IGY holds out
hopes for a safer, more comfortable future for us and our descendants.
As the old year drew to its close so did the massive cooperative scientific
project known as the "International Geophysical Year" - a period which actually
covered eighteen months. Although formally "closed," many of the projects and accumulation
of data will continue on a semi-permanent and/or permanent basis.
Some 30,000 scientists and technicians in 66 countries contributed to this unprecedented
program of global observation and experiment, seeking greater understanding of the
earth's interior, oceans, atmosphere, and the space around it. There were 4000 principal
stations scattered throughout the globe with several thousand additional temporary
and volunteer sites and stations which could be called upon for specific data.
It has been estimated that the U. S. contribution to the program entailed an
expenditure of about $100,000,000 excluding logistic support. The world-wide program
may have cost about $750,000,000. Including logistic support, the total effort may
bring this total up to a billion and a half dollars!
What did this vast sum "buy" ? Although it may be years before all the results
can be completely evaluated, certain findings have emerged which are of immediate
interest and application.
Constant surveillance of the sun during the greatest activity in its known history
permitted the calling of about 40 world-wide "alerts" during which scientists intensified
their observations of the many and varied effects of great solar flares. The scientists
were able to collect unprecedented data on the interrelationships of upper atmosphere
phenomena when the earth passed through a remarkably intense solar cloud on February
11, 1958 causing the best-observed aurora in history. They also had the opportunity
of observing the first man-made aurora in history at Apia, Samoa on August 1, 1958
- a phenomenon evidently related to nuclear testing at the time.
Electronics & Radio
In the field of electronics and radio propagation several interesting effects
were noted which may serve as new transmission media in the future. The fact that
a variety of rockets was available to researchers-both as test instruments themselves
and as vehicles for launching satellites and other high altitude equipment-cannot
be under- estimated. That so much new and interesting data is now available can
be directly attributed to the fact that these giants, basically military weapons,
could be harnessed to the gathering of vital facts about the upper atmosphere.
Probably one of the most significant on-board satellite experiments appears
to be the work of Dr. James A. Van Allen of Iowa in establishing the existence of
equatorial electrojet, a narrowband girdling the earth's magnetic equator and flowing
eastward when the sun is overhead. Data obtained from balloon rockets sent through
the electro jet seemed to indicate that the jet consists of two currents, one atop
the other. The lower extended from 60 to69 miles above the earth while the bottom
of the second current was 73 miles above the earth with the top of the band out
of the range of the "rockoons." This radiation was interpreted as corpuscular in
nature and lead to the conclusion that this great radiation belt around the earth
consisted of charged particles, temporarily trapped in the earth's magnetic field.
The scientists conjectured that the aurora is related to this trapped radiation
and is caused by particle leakage from the belt. This suggests that solar plasma
is the source of particles. These studies, combined with other results obtained
during IGY, begin to relate a variety of atmospheric and spatial phenomena in an
exciting and meaningful way, suggesting that major advances are in the process of
being made and formulated.
 Also of interest were the special studies made regarding the nature of the ionosphere
close to the geographical poles during periods of prolonged solar absence. At the
South Pole Stations, for instance, the ionosphere is subjected to extended exposure
and to solar ionizing radiations during the long summer day while it is screened
for several months during the polar night. This phenomenon might be considered to
have an adverse effect on year-around communications - such as the two-way radio service
required by the trans-polar flights of commercial aircraft. Surprisingly enough,
the IGY investigators found that the ionization reached a summer saturation of about
4.5 x 105 electrons per cubic centimeter which was capable of supporting trans-polar
communications up to 22 mc. Throughout the winter night it was found that the F-layer
persists but that this usually rather uniform layer appeared to break up into cloud
formations. Despite this, a density of 2 x 105 electrons per cubic centimeter-a
typical reading-was sufficient to support transpolar communications up to 14 mc.
in the absence of ionospheric storms.
Considerable work was also done on the subject
of backscatter-both that requiring reflections continuously from large regions and
that where reflection geometry requires the backscatter oblique-incidence technique.
Analysis of the data obtained revealed that tilts in the F-region permit radio-wave
propagation over great distances without ground reflections. Tilts or horizontal
gradients allow the propagation of radio waves over long distances by successive
reflections from the curved F-layer until a particular tilt directs the energy to
earth. Propagation over distances in excess of 6000 miles was a frequently observed
phenomenon.
Another interesting project concerned "whistlers." The data gathered
seems to point to a marked dependence on the frequency of occurrence from place
to place. Activity appeared to increase northward from none at all at Huancayo,
Peru up to Hanover, N. H., where a variety of very-low-frequency phenomena were
recorded, and then diminishes nearly to the vanishing point at Frobisher Bay and
Thule, Greenland.
Another group reported a peculiar signal enhancement on a 49.84
mc. circuit operating between the Philippines and Okinawa - a circuit which had
been set up to measure sporadic-E. The enhancement of the signal strength commenced
about 2 hours after sunset and continued until about midnight, being particularly
strong during the autumnal equinox. This phenomenon seemed to be attributable to
F-region scatter. Studies carried out on the circuit seemed to indicate F-region
reflections from the path mid-point at 187 miles. The returned echo appeared to
be similar to those returned from extensive aurora curtains and may represent blobs
of ionization oriented along the earth's magnetic field.
Other Results
Among other
results obtained by the scientists was evidence that magnetic fields associated
with sunspots revealed them to be as much as 8000 times greater than at the earth's
equator; that the cosmic -ray intensity cycle runs opposite to and somewhat behind
the sunspot cycle; while the existence of magnetic fields in space was due to the
fact that cosmic rays do not approach the earth's magnetic field as expected but
instead show a bias to the west; and that radio signals caused by lightning flashes
curve far out through space to the opposite hemisphere, indicating the existence
of an ionized medium in space denser than anticipated and possibly consisting of
the sun's corona-greatly attenuated.
Information gathered by the satellites in orbit
during the period the IGY studies were under way revealed that the interior satellite
temperatures were controllable within limits of easy human tolerance and that micrometeorite
density was not the problem originally anticipated. Such satellite observations
suggested that the upper atmosphere is at least ten times denser than previously
thought on the basis of ground observations. The satellite trackers detected an
antipodal "echo" of satellite signals, coming from the side of the earth opposite
the satellite, due to the unexpected "ducting" of the signals by the ionosphere.
In the weeks, months, and even years that lie ahead, scientists throughout the civilized
world will be referring to the reams of priceless data patiently garnered by thousands
of skilled specialists stationed throughout the globe -from the icy wastes of the
arctic to the steaming jungles of the tropics. The information they have been able
to collate from instruments soaring high above the earth's surface and miles down
on the ocean floor promises a better and more comfortable existence for mankind-both
in our generation and in the future.
Improved radio communications, more knowledge
about weather forecasting, more information about the space surrounding our earth
in preparation for putting man in space will all grow out of some of the IGY findings.
An additional bonus in the form of freely extended international cooperation between
"traditional enemies" may have a far-reaching effect which can't be evaluated on
the data-processing machines but may make itself felt in the slackening of international
tensions and a freer exchange of data among the world's scientists.
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