Earth & Cosmos / Space & Astronomy

Radio astronomy

Karl Jansky detected radio waves from the centre of the Milky Way in 1932-33, opening a window beyond visible light.

Karl Jansky at Bell Labs was tracing static that disturbed transatlantic radio-telephone links when he found a steady hiss that rose and fell once per sidereal day, coming from the direction of the Milky Way's centre (reported 1933). Grote Reber built the first dish telescope in his Illinois garden in 1937. After wartime radar progress, radio astronomy found quasars, pulsars and the cosmic microwave background.