A radio interferometer was invented by merging radio astronomy with computer technology.

Radio astronomy began in the 1930s when Karl Jansky (1905-1950) built a radio receiver designed to locate interference that was plaguing long distance telephone communications. His discovery of radio signals coming from space created a sensation in 1933.

The first actual radio telescope was invented when Grote Reber built a 29.5-ft (9-m) parabolic dish receiver in 1937. With it he was able to create a map of numerous radio sources in the sky.

In the case of optical telescopes, the greater the aperture, the more light can be gathered. Likewise, the greater the area of the radio telescope dish, the more radio waves detected. Unfortunately, radio waves are at the low end of the electromagnetic spectrum. These wavelengths are long and stretched out. A really gigantic dish is needed to produce sharp resolution of radio objects...