Karl Jansky

American physicist and radio engineer at Bell Telephone Laboratories who, while investigating sources of static interfering with transatlantic radio-telephone service, discovered in 1932 that a component of the radio noise he recorded recurred on a period matching the sidereal day rather than the solar day, and traced its source to the direction of the constellation Sagittarius, toward the center of the Milky Way. Published in 1933, it was the first detection of radio waves from an astronomical source beyond the solar system, founding the field of radio astronomy, though Jansky himself used a rotatable directional antenna array nicknamed Jansky's merry-go-round rather than a purpose-built telescope, and never built one.