Karl Jansky, an engineering working at Bell Labs., studying the origin of static noise from thunderstorms, in the early 1930s.
Using a Bruce curtain antenna at 20.5MHz was able to identify one particular kind of radio noise of unknown origin and its origin seemed to move as earth rotated. Further investigation let him to identify that it was coming for a fixed point of the sky…he just become the first radio astronomer.
This new science, Radio Astronomy, has revealed some important things like our position into our galaxy, relevant facts that support the Big Bang theory, exotic object like pulsars. Maybe more than 60% of our actual knowledge in astronomy and astrophisic comes from this pretty recent science.