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Radio Astronomy – Listening to Space

    It is said that there is no sound in space. But radio astronomy allows people to literally listen to it. “Radio astronomy is the study of celestial objects that give off radio waves” (NSF). It is a branch of astronomy solely focused on the ‘radio’ part of the electromagnetic spectrum. Using this, scientists’ study celestial objects which give off radio waves. Radio astronomy helps people analyze cosmic happenings that are invisible on the electromagnetic spectrum. It’s the study of the universe using radio emissions. 


    Radio astronomy started in 1932, when Karl G. Jansky, engineer, solved a puzzling problem: there was noisy static that was interfering with the short-wave radio for the transatlantic voice communications. After trying to find the source for moths, he discovered that it was moving across the sky. After discussing with some astronomers, he found that some radio waves from outside the solar system – in the center of the Milky Way – were the cause of the problem. But one of the most famous radio astronomy discoveries happen in 1967 when Jocelyn Bell so a strange signal in a printout from the radio telescope she helped build. After a lot of research, it was identified that the signals were coming from a pulsar, which is a “massive star [that] collapses and then explodes as a supernova” (NSF). There has been a lot more research in this field since, and radio astronomy only grows in popularity.

How It Works  


    A radio telescope is a tool that a radio astronomer could use. They see invisible/hidden behaviors and actions sensed in the universe. They are used by scientists to solve the baffling mysteries that the cosmos presents. For eons, humans could only explore space with what we can see – the visible part of the spectrum. But that is only a microscopic amount out of the universe’s electromagnetic spectrum. They help astronomers discover things about objects, like the planets in our solar system. “It was first believed that Mercury’s rotational period matches its orbital period which is 88 Earth days. However, in 1965, Gordon Pettengill and Rolf Dyce…[used] the then 300-meter Arecibo Radio Observatory in Puerto Rico” (Trek). They have special antennae that they use to find radio waves from sources in the sky. They are the main tool for radio astronomers. 

The Electromagnetic Spectrum

    The electromagnetic spectrum is a range of frequencies and their wavelengths over which electromagnetic radiation extends. Radio waves cover a huge area of the electromagnetic spectrum. The wave lengths range from 1 meter to 100s of kilometers - radiation. Though they are usually portrayed or shown as sound, they are part of the same spectrum as visible light. Radio telescopes detect natural radio waves in space. The bigger the dish, the better the resolution. Th ALMA radio telescope will soon be the most powerful telescope on earth. So far, the furthest thing we can see is a quasar - a distant galaxy over 12 billion lightyears away. We can see it because at the center is a super massive 
black hole. The eat over 300 planet earths a minute, and this causes a lot of energy. This emits all sorts of waves all over the spectrum. Including radio waves, which the telescope sees. 

Diagram of a Radio Telescope:

    In summary, radio astronomy is the study of objects in space that emit radio waves. They detect waves from the invisible part of the electromagnetic spectrum. Most radio astronomers use radio telescopes, which use their antennae to find radio waves that celestial objects radiate.


“Radio Astronomy Archive.” National Radio Astronomy Observatory,
“The History of Radio Astronomy.” National Radio Astronomy Observatory, 20 Jan. 2022,
Miller, James. “Top Astronomical Discoveries Made by Radio Telescopes.” Astronomy Trek, 7 Nov. 2018, 
“What Is Radio Astronomy?” Sky & Telescope, 20 Apr. 2020,
“Grote Reber’s First Radio Telescope.” NRAO, Accessed 30 Nov. 2022. 
Thesecretsofnature, director. YouTube, YouTube, 2 May 2014, 


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