The radio window

Using charts and photos, Edward McClain, of the Radio Astronomy branch of the U.S. Naval Research Lab, and Bernard Burke, of the Carnegie Institute of Washington, DC, discuss the "radio window," a larger wavelength band than the optical one for making earth-based observations of space. In 1932, Karl Jansky, from Bell Labs, discovered radio noise from space. Five years later Grote Reber built the first antenna for astronomical observations. The sun was discovered to be a source of radiation and radio waves, as were the Milky Way and Crab Nebula. Later J. G. Bolton and J. G. Stanley discovered a variable source of cosmic radio frequency radiation in the constellation Cygnus. That plus Cassiopeia are the most intense radio sources in the heavens. Additional research resulted in Martin Ryle's development of interferometric techniques, A. E. Lilly's observation of the spiral structure of the universe, and J. H. Oort's mapping of our own galaxy. In 1944, H. Van de Hulst predicted that a hydrogen cloud produces radiation in the radio range of 21cm wavelength. E. Purcell and H. Ewen confirmed this theory, detecting a 21cm cosmic gas emission from neutral hydrogen in the Milky Way in 1951. Ohio University's John Kraus was instrumental in detecting the Milky Way's radio transmissions. In 1955, the Mills Cross Array, a simple radio antenna built by Australian B. Mills, was used to record the radio noise produced by the planet Jupiter. The antenna most commonly used is the paraboloidal reflector with a diameter of 80-90 ft. The largest steerable radio reflector is at Jodrell Bank in the UK. Plans for the National Radio Astronomical Observatory at Green Bank, West Virginia are underway at the time of this program. Increasing research will help to explain whether the explosion theory or the continuous creation theory of the universe is more valid.