Radio astronomy

Radio astronomy is the study of celestial phenomena through measurement of the characteristics of radio waves emitted by physical processes occurring in space. Radio waves are much longer than light waves. In order to receive good signals, radio astronomy requires large antennas, or arrays of smaller antennas all working together (The Very Large Array near Socorro, New Mexico is an example of this). Most telescopes use a parabolic dish to reflect the waves to a receiver which detects and amplifies the signal into usable data. This allows astronomers to see a strip of the radio sky. If they take multiple scans of overlaping strips of the sky they can piece together an image using a false color technique. Radio astronomy is a relatively new field of astronomical research that still has much more to be discovered.

Developments

Radio astronomy has led to substantial increases in astronomical knowledge, particularly with the discovery of several classes of new objects, including pulsars, quasars and radio galaxies. This is because radio astronomy allows us to see things that are not detectable in optical astronomy. Such objects represent some of the most extreme and energetic physical processes in the universe.

Related Topics:
Pulsars - Quasars - Radio galaxies

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Radio astronomy is also partly responsible for the idea that dark matter is an important component of our universe; radio measurements of the rotation of galaxies suggest that there is much more mass in galaxies than has been directly observed (see Vera Rubin). The cosmic microwave background radiation was also first detected using radio telescopes. However, radio telescopes have also been used to investigate objects much closer to home, including observations of the Sun and solar activity, and radar mapping of the planets.

Related Topics:
Dark matter - Galaxies - Vera Rubin - Cosmic microwave background radiation - Sun - Planets

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Radio telescopes can now be found all over the world (see List of radio telescopes). Widely separated telescopes are often combined using a technique called interferometry in order to obtain observations with much higher resolution than could be obtained using a single receiver. Initially telescopes within a few kilometres of each other were combined (see, for example, the Mullard Radio Astronomy Observatory), but since the 1970s telescopes from all over the world (and even in Earth orbit) have been combined to perform Very Long Baseline Interferometry.

Related Topics:
List of radio telescopes - Interferometry - Mullard Radio Astronomy Observatory - Very Long Baseline Interferometry

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The United States government has established an institution to conduct radio astronomy research in the US, titled the National Radio Astronomy Observatory (commonly abbreviated as NRAO). This institution controls various radio telescopes around the United States included the world's largest fully mobile radio telescope, the Green Bank Telescope. The United States government has also set aside a national radio quiet zone for radio astronomy research centered around Green Bank, West Virginia. As a result, Green Bank is now the home of NRAO's primary facility.

Related Topics:
National Radio Astronomy Observatory - Green Bank Telescope - National radio quiet zone - Green Bank, West Virginia - NRAO

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See also: Very Long Baseline Interferometry aperture synthesis

Related Topics:
Very Long Baseline Interferometry - Aperture synthesis

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