272 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1959 
may have to take off from the polar regions, escaping, so to speak, 
through the hole of the doughnut.) An interesting possibility is that 
similar belts may become useful as aids in detection of magnetic fields 
of other planets. 
Cosmic rays.—Cosmic rays are another important factor of the space 
environment, with various consequences for the earth. ‘They are 
charged particles of ordinary matter like those propelled from the 
sun, but generally of cosmic origin and of vastly greater energies— 
some are believed to travel at speeds near that of light and to carry 
energy up to 10” electron volts—a billion times that achieved in man’s 
best particle accelerators. They may represent half of all the energy 
in the universe. Through rocket and satellite observations, we know 
that such high-energy, or primary, cosmic rays are characteristic of 
space above the atmosphere and that in collisions with atmospheric 
molecules they produce showers of breakdown products of lower 
energy, called secondary cosmic rays, which reach lower levels. The 
sun has been found to influence cosmic-ray behavior near the earth, 
confronting us with an important factor in the study of magnetic space 
fields and magnetic storm effects. Cosmic rays display diminished 
intensity in general during sunspot activity, but there are shorter 
period fluctuations not so related. High-altitude aircraft observations 
of cosmic rays provided evidence leading to some refinement of our 
ideas about the configuration of the geomagnetic field at those and 
higher altitudes. 
High-atmosphere phenomena.—Our outer atmosphere is thus under 
radiation of various types—X-rays, ultraviolet light, hard and soft 
cosmic rays, and charged particles from space or the radiation belts, 
which enter along lines of magnetic force. A whole family of related 
phenomena results. Under radiation the atmospheric gases produce 
the luminous effects of aurorae and airglow. Ionization of the thin 
outer gases occurs in layers comprising the ionosphere. These sheets 
of ions reflect or refract electromagnetic waves, providing the basis of 
long-distance radio communication, and they support electric-current 
systems and magnetic fields in grand patterns. 
When the radiation becomes irregular, as at times of solar disturb- 
ances, the ionization is chaotic. Radio signals fade or black out, and 
the changing magnetic fields produce geomagnetic unrest and mag- 
netic storms. Solar activity, radio-wave propagation disturbances, 
auroral displays, and magnetic storms had therefore to be considered 
together in broadly comprehensive views during the IGY. 
The tonosphere.—This feature is in fact a series of concentric shells 
of ionized gases about the earth in configurations determined by the 
gas densities and chemical compositions. IGY observers carried out 
continuous intensive monitoring of the ionosphere, using vertical-inci- 
