SADARS

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30 June 2016 - 83 YEARS OF RADIO ASTRONOMY

Posted: 01 Jul 2016 03:33 AM PDT
http://www.sadars.co.uk/archives/1293




Atacama Large Millimetre (and sub-millimetre) Array
Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* Credit: ALMA (ESO/NAOJ/NRAO)

A nearly full house heard Paul Hyde explain that it was more than 83 years,
since Paul Jansky began investigating the static which was proving
problematic to transatlantic radio telephony in 1929. Â* Â* Â* Â* Â* Â* Â* Â*Â*
Jansky had built a large receiving array to scan the skies in an attempt to
find the source of the noise. Apart from static from thunderstorms there
was an emission from the sky near the location of Sagittarius. Other
astronomers couldnt accept the finding, but in1940 another astronomer,Â*
Grote ReberÂ* ( W9GFZ) from Chicago published his findings from his 9 meter
dish at 160MHz. Jansky and Reber went on to map the sky and the first
survey was published in 1944. Radio Astronomy as we now know it was
underway, except that findings made during ww2 were classified and many who
worked in astronomy were put to work in Radar.

Paul detailed the work that continued during and after the war which
improved reception and resolution. It was explained how several aerials
could be used at once and the results joined in a Correlator, a powerful
computer able to combine the signals into one output. More signal sources
in space were found and investigated resulting in discoveries ofÂ* Pulsars,
Blazars, Quasars and Radio Galaxies. Doppler Shift was discovered and how
to make use of the Hydrogen lines on the spectrum.

Paul pointed out that as of 2003, Astronomers knew that in the Universe
Dark Energy amounted to 73% and Dark Matter to about 22%, which leaves us
knowing about the remaining 4%!