By sweeping his rotating radio detector back and forth, Bell Labs engineer Karl Jansky identified the first deep-space radio signals. A NEW VIEW Grote Reber, a radio engineer working in Illinois, built the world s first true radio telescope in his spare time and by 1941 had completed a crude survey of the radio sky. At the center is a dense, rapidly rotating stellar cinder that gives off radio flashes 30 times per second. They are probably powered by gas falling into a black hole. The COBE satellite, launched in 1989, carried the study of microwaves into space and confirmed that the universe began in a hot fireball.
Visible light is only one way to look at the universe.
Each strip below shows the plane of our galaxy in a different part of the electromagnetic spectrum, revealing unique information. Radio continuum is from hot, electrically charged gas. Atomic hydrogen emission comes from warm gas. Molecular hydrogen lies in cold clouds, where stars form. Visible light is mostly from sunlike stars.