Radio Telescopes: Listening to the Universe

Radio telescopes detect radio waves instead of visible light from space.
They revealed phenomena invisible to optical telescopes, like pulsars and quasars.
The first radio telescope was built by Karl Jansky in the 1930s.
Some use giant single dishes, like the Arecibo Observatory (before its collapse in 2020).
Arrays like the Very Large Array (VLA) in New Mexico combine many dishes for sharper detail.
Radio telescopes can operate day or night, and even in cloudy weather.
They map cosmic microwave background radiation—the universe’s afterglow from the Big Bang.
Radio astronomy helps search for signals from extraterrestrial intelligence (SETI).
The upcoming Square Kilometre Array (SKA) will be the largest radio telescope ever built.
By “listening” to space, radio telescopes have transformed our understanding of the cosmos.