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Session 30 - Radio Astronomy, Yesterday, Today and Tomorrow - I.
Oral session, Tuesday, June 11
Extraterrestrial radio waves were first detected in 1931-32 by Karl Jansky at the Bell Telephone Labs in New Jersey while he was investigating sources of interference to recently opened, trans-Atlantic shortwave (20 MHz) radiotelephone circuits. At this time Jansky was only a few years beyond his physics degree from the University of Wisconsin, where his father was a professor of engineering. Jansky studied this "star noise" off and on until 1935, establishing that the emission came from the direction of the Milky Way and the galactic center, but did not pursue it in any further detail. The only other person to make a significant contribution to the nascent subject before World War II was Grote Reber, an electrical engineer who worked for several different radio firms in Chicago. After reading Jansky's articles, in 1937 Reber decided to build a 30-ft diameter dish antenna in the backyard of his suburban home in Wheaton, Illinois. By 1939 he had detected the Jansky radiation, which he called "cosmic noise", at 160 MHz and he comenced a long term program of mapping it in detail (with a 12 degree beam). Reber became a well-known figure to the astronomers at the University of Chicago and Yerkes Observatory (Struve, Greenstein, Kuiper, Henyey, Keenan) as he sought to learn astronomy and convince the staff that this cosmic noise was of importance. Struve, editor of the "Astrophysical Journal", was finally persuaded to publish Reber's articles. During and just after the war Reber extended his work to 480 MHz. He then sought funds to move his dish to a quieter locale and to build a second, much larger dish, but neither of these plans came to fruition. It is ironic that the remarkable contributions of these two pioneers to the field that would eventually become known as "radio astronomy" (a term only introduced in the late 1940s) had little influence on the spectacular growth of the field in the decade after World War II. The great bulk of the important work was done in England and Australia, where it grew wholly independently out of wartime radar labs. Reasons for the lag in the US, largely due to the effects of military funding and the strong community of (optical) astronomers, will be discussed.
Program listing for Tuesday