Radio 'Ear' on the Universe Being Built
The primary message of this article is that astronomy is no longer
confined to the realm of optical observations – new technologies allow
astronomers to look at radio waves emitted by objects in the Solar
System and beyond.
Radio was the first non-optical portion of the electromagnetic spectrum
to be explored by astronomers. This article introduces students to
this fact, and that radio astronomy was flourishing in the 1950s.
This article sets the stage for the further expansion of
astronomy into the X-ray
and microwave regions of the spectrum, which become quite important in
the 1965 and 1993 issues of Cosmic Times.
Radio astronomy had its origins in the early 1930s, when Karl Jansky
was investigating the sources of noise in a radiotelephone system at
Bell Telephone Labs in New Jersey. He linked the source of the noise
to something in the sky, rather than the immediate surroundings. He
identified the source to be the center of our Galaxy.
Most astronomers took little notice of this discovery. Grote Reber, a
radio engineer and amateur astronomer, learned of the discovery in
1933 and built his own radio telescope. By the early 1940s Reber had made
detailed maps of the radio sky.
The impetus for the advancement of radio astronomy were the
necessities and technological advances from World War II. The
necessities included classified work
by the British to determine the source of the jamming of British
radars - which turned out to be the Sun. New receivers built for the
War provided the basis for new radio telescopes after the War. By
the early 1950s, Martin Ryle and Antony Hewish had started the Cambridge
catalogues ("2C" and "3C") of radio sources. By the mid 1950s, radio
astronomy was flourishing.
Jodrell Bank, which is 25 miles south of Manchester, England,
was first used for radio astronomy when Bernard Lovell
brought surplus WW II radio equipment there in 1945. Jodrell Bank
Observatory was
expanded in 1952, offering a place to build the Mark I telescope.
The Mark I telescope at Jodrell Bank was completed in
1957, and later became known as the Lovell Telescope, named for the
observatory's founder. Shortly after its completion, it tracked the
booster rocket that carried Sputnik 1 into orbit. The Lovell Telescope
remains the third largest steerable radio telescope in the world.
The Lovell Telescope has been used to track a number of planetary
probes. It has been used extensively for astronomy research,
including the study of pulsars, star-forming regions, quasars, and
gravitational lenses.
In the Cosmic Times article, the "brightest radio emitter ... in the
constellation Cassiopeia" is Cassiopeia A, later found to be a
supernova remnant. Cassiopeia A is now extensively studied to understand the
nature of supernova explosions, formation of chemical elements, and
how the remnant interacts with the surrounding interstellar gas.
Other resources
The following web pages have more detailed information:
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