Grote Reber

Grote Reber (December 22, 1911 – December 20, 2002), was an amateur astronomer and pioneer of radio astronomy. He was instrumental investigating and extending Karl Jansky's pioneering work, and conducted the first sky survey in the radio frequencies.

Life

Reber was born and raised in Wheaton, Illinois, a suburb of Chicago, and graduated from Armour Institute of Technology (later Illinois Institute of Technology) in 1933 with a degree in radio engineering. He was an amateur radio operator (ex-W9GFZ), and worked for various radio manufacturers in Chicago from 1933 to 1947. When he learned of Karl Jansky's work in 1933 [http://select.nytimes.com/gst/abstract.html?res=FA091FFB3E5C16738DDDAD0994DD405B838FF1D3&scp=20&sq=karl%20jansky&st=cse] , he decided this was the field he wanted to work in, and applied to Bell Labs where Jansky was now working. However this was during the height of the Great Depression and there were no jobs available.

Instead Reber decided to build his own radio telescope in his back yard in Wheaton. His design was considerably more advanced than Jansky's, consisting of a parabolic sheet metal mirror 9 meters in diameter, focusing to a radio receiver 8 meters above the mirror. The entire assembly was mounted on a tilting stand allowing it to be pointed in various directions, although not turned. The telescope was completed in 1937.

First^* Radio Telescope - Wheaton, IL 1937

Reber's first receiver operated at 3300 MHz and failed to detect signals from outer space, as did his second, operating at 900 MHz. Finally his third attempt at 160 MHz was successful in 1938, confirming Jansky's discovery. Reber turned his attention to making a radio-frequency sky map, which he completed in 1941 and extended in 1943. He published a considerable body of work during this era, and was the initiator of the "explosion" of radio astronomy in the immediate post-WWII era.

During this time he uncovered a mystery that was not explained until the 1950s. The standard theory of radio emissions from space was that they were due to black-body radiation, light (of which radio is a non-visible form) that is given off by all hot bodies. Using this theory one would expect that there would be considerably more high-energy light than low-energy due to the presence of stars and other hot bodies. However Reber demonstrated that the reverse was true, and that there was a considerable amount of low-energy radio signal. It was not until the 1950s that synchrotron radiation was offered as an explanation for these measurements.

Reber sold his telescope to the National Bureau of Standards, and it was erected on a turntable at their field station in Sterling, VA. Eventually, the telescope made its way to NRAO in Green Bank, West Virginia ^{Sullivan 1984} , and Reber supervised its re-construction at that site. Reber helped with a reconstruction of Jansky's original telescope as well.

In the 1950s he wanted to return to active studies but much of the field was already filled with very large and expensive instruments. Instead he turned to a field that was being largely ignored, that of very low-frequency, hectometre, radio signals in the 0.5-3MHz range around the A.M. broadcast bands. However signals with frequencies below 30 MHz are reflected by an ionized layer in the Earth's atmosphere, called the ionosphere, so Reber moved to Tasmania, a triangular island off the southern coast of Australia where, on very cold, long, winter nights the ionosphere would, after many hours shielded from the sun's radiation by the bulk of the Earth, 'quieten' and de-ionize, allowing the long radio waves in to his antenna array. Tasmania also offered low levels of man-made radio noise which permitted the reception of the faint signals from outer space.

In the 1960s he had an array of dipoles set up on the Sheep Grazing property of Deniston, about 5Km north of the town of Bothwell, where he lived in a house of his own construction he decided to build after he purchased a job lot of coach bolts at a local auction. He imported Oregon pine direct from a sawmill in Oregon, huge beams, "8x4", and high tech double glazed window panes, also from the U.S. He bolted the house, of his own design, together with the bolts. The window panes formed a north facing passive solar wall, heating mat black painted, dimpled copper sheets, from which the warmed air rose by convection. The house was so well thermally insulated that the oven in the kitchen was nearly unusable because the heat from it, unable to escape, would raise the temperature of the room to over 50⁰C, (100⁰F).

His house was never completely finished, it was meant to have a passive heat storage device, basically a thermally insulated pit full of dolerite rocks, underneath, but although his mind was sharp, his body started to fail him in his later years, and he was never able to move the rocks. He was fascinated by mirrors and had at least one in every room. One of the ironies of Grote Reber's life, is that he lived twice as long as Carl Jansky.

He had one of the amplifiers from the prime focus of his first telescope, pictured above, probably the one used at 900 MHz, it was a compact point-to-point construction and used two R.C.A. type 933 'acorn' thermionic valves. All the rubber insulated wires in it had perished and the rubber was hard and crumbly. He powered this amplifier, and all his later receivers at Deniston, from batteries, to avoid interference entering the equipment along power cables.

Reber was not a believer of the "big bang" theory, he believed that red shift was due to repeated absorption and re emission or interaction of light and other electromagnetic radiations by low density dark matter, over intergalactic distances and he published an article called "Endless, Boundless, Stable Universe", which outlined his theory.

He was looked after in his final days at the Ouse District Hospital 30Km north east of Hobart, Tasmania, where he died two days before his 91st birthday, (2002). His ashes were spread mainly on Mt. Rumney, east of Hobart, according to his wishes, because at Mt. Rumney, he collected more data on extraterrestrial radio sources at hectometre wavelengths in one week, than he had obtained in many years of work in the U.S. This was because Mt. Rumney was a "clean" site, free from contamination by terrestrial radio transmitters and on very cold winter nights the ionosphere would settle and become transparent, allowing terrestrial hectometer radio transmissions out and extra terrestrial emissions in. (The nearest broadcast transmitter was A.B.C. Radio 7ZL/7ZR, with a quarter wave ground plane, dual tuned antenna, on the mudflats at Lauderdale, at 603 and 936 kHz and about 10 kW E.F.R. ?, 5km away).Some of his ashes were taken and distributed among 24 major radio observatories around the world, including:

*Dwingeloo Radio Observatory
*Goldstone Apple Valley Radio Telescope
*Jodrell Bank
*Molonglo Observatory, Bungendore, New South Wales, Australia
*Mullard Radio Astronomy Observatory

Honorary Awards

*Bruce Medal (1962)
*Henry Norris Russell Lectureship (1962)
*Jackson-Gwilt Medal of the Royal Astronomical Society (1983)

Named after him

*Asteroid 6886 Grote
* The Grote Reber Medal [ [http://www.qvmag.tas.gov.au/reber.html "Queen Victoria Museum and Art Gallery"] ]
*Museum at the Launceston Planetarium, opened 20 January 2008 [ [http://www.abc.net.au/news/stories/2008/01/18/2141221.htm Museum marks life of first radio astronomer] , Australian Broadcasting Corporation, 18 January 2008 (accessed 24 January 2008)]

References

* Sullivan, W.T. (1984). "The Early Years of Radio Astronomy". Cambridge University Press. ISBN 0-521-25485-X pg 48

* The Early Years of Radio Astronomy, W.T. Sullivan III ed. pg 48

External links

* [http://adsabs.harvard.edu/abs/2003BAAS...35.1472K Bulletin of the American Astronomical Society obituary] ]
* [http://www.guardian.co.uk/science/2003/jan/03/obituaries.spaceexploration Guardian obituary] ]
* [http://www.timesonline.co.uk/tol/comment/obituaries/article807500.ece Engineer whose invention of the radio telescope - built in his back garden - transformed postwar astronomy]
* [http://www.nrao.edu/whatisra/hist_reber.shtml Grote Reber]
* [http://www.setileague.org/admin/reber.htm Grote Reber, ex-W9GFZ]
* [http://www.abc.net.au/news/stories/2008/01/18/2141221.htm Museum marks life of first radio astronomer (includes modern photo of Reber)]

ee also

* Reber Radio Telescope
* John D. Kraus
* Astronomical radio source