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.

History

Nikola Tesla in the Colorado Springs lab recorded cosmic waves emitting from interstellar clouds and red giant stars. He observed repeating signals conducted by his transceiver. He announced that he received extraterrestrial radio signals. Tesla stated that he received signals from planets in some of the scientific journals of the time. The scientific community did not believe him, primarily because research of cosmic signals did not exist (what is known today as radio astronomy), and the community of science rejected Tesla's data. Tesla spent the latter part of his life trying to signal Mars.

Related Topics:
Nikola Tesla - Colorado Springs

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One of the earliest modern investigations into extraterrestrial sources of radio waves were by Karl Guthe Jansky, an engineer with Bell Telephone Laboratories, in the early 1930s. The first object actually detected was the center of the Milky Way, followed by the sun. These early discoveries were confirmed by Grote Reber by 1938. After World War II, substantial improvements in radio astronomy technology were made by astronomers in Europe and the United States, and the field of radio astronomy began to blossom. One of the most notable developments came in 1946 with the introduction of radio interferometry (see, for example, Nature 158 pp 339 1946) by Martin Ryle's group in Cambridge (who obtained a nobel prize for this and later aperture synthesis work), also the Lloyd's mirror interferometer developed independently in 1946 by Joseph Pawsey's group at the University of Sydney (see Nature 157 pp 158 1946). Two issues, one astronomical and one technical, dominated the research in Cambridge, from the late 1940's for more than thirty years. What was the nature of the discrete radio sources, or `radio stars'? Where were they, what were they, what were their properties, how many were there, how did they work and what was their significance in the Universe? Of parallel importance was the puzzle of how to devise new kinds of radio telescope which would elucidate these astronomical questions.

Related Topics:
Karl Guthe Jansky - Bell Telephone Laboratories - Milky Way - Sun - Grote Reber - World War II - 1946 - Interferometry - Martin Ryle - Group in Cambridge - Nobel prize - Aperture synthesis - Joseph Pawsey's - University of Sydney

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See also: History of astronomical interferometry

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