In 1931, Karl Jansky was hired by AT&T to search for sources of static that might interfere with radio waves for transatlantic communications. Jansky identified static from thunderstorms and random radio noise from devices on Earth, but he also found a radio hiss from the Milky Way galaxy. After World War II, astronomers constructed more radio telescopes with greater sensitivity to faint radio signals from space. In the 1970s, the National Radio Astronomy...