Transport of Cosmic Radiation

Abstract

The theory of electromagnetic radiation was first derived by James Clerk Maxwell in 1873. He showed that both magnetic and electric fields propagate in space and the velocity of propagation, from purely magnetic and electrical measurements, was very nearly 3×10⁸ m/s. Within the limits of experimental error, this was equal to the velocity of propagation of light. Within fifteen years of Maxwell’s discovery, Heinrich Hertz succeeded in producing electromagnetic radiation at microwave frequencies by installing a spark gap (an oscillating high-potential arc discharge across two conductors separated by a short gap) at the center of a parabolic metal mirror. While the induction field was significant in Hertz’s measurements (1.5 m transmitter-receiver separations), Gugliemo Marconi succeeded in demonstrating true electromagnetic energy transport, first at separations of 9 meters, then 275 meters, then 3 kilometers, and then, in 1901, across the English Channel. Finally, in 1901, Marconi’s transmissions bridged the Atlantic Ocean—a distance of 3, 200 kilometers.