Grote Reber

views updated May 21 2018

Grote Reber

Grote Reber (born 1911) was a radio engineer who became interested in radio astronomy as a hobby. He built the first radio telescope in the backyard of his home and, for a decade, he was the only radio astronomer in the United States. Reber recorded radio signals at different wavelengths and created the first radio map of the universe.

Grote Reber was born on December 22, 1911 in Wheaton, Illinois, about 25 miles west of Chicago. His mother, Harriet Grote, was a grade school teacher who interested Reber in astronomy with a book by one of her former students, Edwin P. Hubble. As a child, Reber was interested in radio as a hobby. By the time he was 15 years old he had built his first transmitter receiver and could communicate with other "ham" radio amateurs around the world.

In 1933 Reber graduated from the Illinois Institute of Technology with a Bachelor of Science degree in electrical engineering. After graduation he went to work for a Chicago radio manufacturer, the Stewart Warner Company, where he designed radio receivers. During the same year, Karl Jansky published his first report describing how he had detected the first radio waves from outer space. Reber read Jansky's report and was inspired to pursue these signals himself.

Karl Guthe Jansky was a physicist at Bell Telephone Laboratories in Holmdel, New Jersey. In 1927 Bell had created the first transatlantic radiotelephone. However, the telephone links were highly susceptible to electrical interference. In 1930 Jansky was asked to locate the source of the interference. Within two years Jansky discovered three sources of the problem, two of which were related to storms and the third came from an unknown origin. Jansky pursued this third source and discovered that it appeared four minutes earlier each day, which corresponded to the 23 hour 56 minute period of the stars. This meant that the stars emitted energy in the form of radio waves, as well as light waves. Jansky followed up this work with another report in 1935 which linked the radio waves to the distribution of the Milky Way.

Jansky was then assigned to work on other projects at Bell Laboratories and never had the opportunity to continue his work on stellar radio waves. However, Reber read Jansky's work in the Proceedings of the Institute of Radio Engineers journal and was determined to continue his work. He first needed to build a telescope capable of detecting cosmic radio waves. In the midst of the Great Depression, Reber was unable to garner academic or financial support for his project. Astronomers were not familiar with radio technology and were still absorbed with visual inspections of the universe. Reber was not discouraged by this lack of enthusiasm and was determined to work on the project alone.

Built First Radio Telescope

Reber drew up plans to build a large parabolic reflector to collect radio waves and feed them into a radio receiver. He presented his plans to the American Bridge Company, which quoted him a price of $7,000 to build the telescope. Since this price was not affordable to Reber, he decided to construct the device himself. With the help of two friends, Reber built a reflector out of galvanized sheet metal and wooden rafters. The mirror was 31 feet in diameter with a focal length of 20 feet. With no external financial support, Reber spent $1,300 of his own money to build the first radio telescope in the backyard of his home in Wheaton. This was $300 more than the price of a new automobile. The telescope took four months in 1937 to build, but stood in Reber's yard for ten years.

Once the telescope was in place Reber went to work trying to confirm Jansky's findings. He worked at Stewart Warner during the day and recorded signals in his backyard at night when there was less interference from cars. Reber originally chose to operate the telescope at a wavelength of nine centimeters. However, after a year, he failed to detect anything with his telescope. In 1938 he made several improvements to his telescope using parts from his employer and from the University of Chicago and he decided to increase the wavelength to 33 centimeters. Reber was still unsuccessful. A year later he increased the wavelength to 1.87 meters. After two years of trying to detect cosmic radio waves, Reber was finally successful at this longer wavelength.

Major Discoveries

Once Reber had an operational telescope he set out to make a radio map of the Milky Way. First he confirmed Jansky's claim that the static was strongest at the constellation Sagittarius, the center of the universe. He also detected strong signals from other constellations, namely Cygnus, Cassiopeia, Canis Major, and Puppis. Reber published his initial findings in the Proceedings of the Institute of Radio Engineers. He also tried once again to get astronomers interested in radio waves. Reber submitted his paper to the Astrophysical Journal, but there was no one qualified to review the paper. As Reber explained in a January 1988 article in The Toronto Star, "The astronomers couldn't understand the radio engineering and the radio engineers couldn't understand the astronomy." The editor of the journal decided to publish the paper without a review and it finally appeared in June of 1940.

Reber continued to improve his telescope and map the universe. In 1943 he started to explore the Sun and found strong radio signals. This discovery had already been made accidentally by the British a year earlier but had remained a military secret until after World War II. Reber completed the first radio map of the galaxy in 1944 based on over 200 chart recordings. He also noted that radio waves could penetrate the interstellar dust that blocks the view of the Milky Way. This was an important improvement over visual inspections of the universe.

For nearly a decade Reber worked alone in his backyard as America's only radio astronomer. However, once Reber's findings were circulated among astronomers and once World War II was over, interest in the field began to grow. Reber stopped his operations in Wheaton in 1947 and moved his telescope to the United States Bureau of Standards. In 1948 Reber went to work at the University of Virginia as the chief of the experimental microwave radio section. In 1951 he moved to Hawaii to work in an area that had less man-made radio interference. He used a telescope that worked at 5.5 to 14 meters to try to find new sources of radio waves. He left his original telescope behind and it was moved in 1960 to the National Radio Astronomy Observatory in Green Bank, West Virginia, where it is still on public display.

Moved to Tasmania

In 1954 Reber moved to Tasmania, off the coast of southern Australia, to be closer to the south magnetic pole where the Earth's ionosphere was the weakest and, therefore, radio waves were the strongest. He joined the Commonwealth Scientific and Industrial Research Organization and constructed a new wire-antenna instrument over 3,000 feet in diameter that measured wavelengths at 150 meters. It is one of the world's largest radio telescopes. Aside from a brief period between 1957 and 1960 when Reber worked for the National Radio Astronomy Observatory, he spent the rest of his life in Tasmania. One of his first projects there was to map the southern radio sky. He found that the southern map was the inverse of what he had mapped in Illinois at much shorter wavelengths.

Even in Tasmania Reber's work was still hindered by the ionosphere. While the ionosphere protects the Earth from long-wave radiation from space, it also prevents certain radio frequencies from escaping. In 1985 Reber used a mission of the space shuttle Challenger to his advantage. Exhaust gases from the space shuttle's engines temporarily neutralized the electrical particles in the ionosphere. Therefore, on August 4, 1985 when Challenger was over Reber's telescope in Hobart, Australia, the shuttle released a quarter ton of fuel to create a hole in the ionosphere for a few hours. Through this hole Reber was able to find cosmic radiation at a wavelength of 176 meters, which was the first time radio waves of this length from space had ever been recorded.

Reber's next project took him to the other end of the Earth. He took advantage of a solar minimum of 1986 and 1987 to try to map the northern sky at 144 meters to match his southern sky map at that same wavelength. He spent two winters as a visiting scientist at the National Research Council of Canada working with an antenna at Ashton, southwest of Ottawa. However, the antenna was a part of some obsolete defense equipment and was badly damaged, so Reber was unable to complete his map.

Challenged Big Bang Theory

Reber continued to work into the next decade, when he was in his eighties. He was trying to find more ways to create holes in the ionosphere so that he could get more data from longer wavelengths. Reber believed that these data were key to disproving the Big Bang theory of how the universe evolved. His radio maps of space have shown that the radio sky is brighter at longer wavelengths than shorter wavelengths. Reber believes that this is due to photons losing energy as they travel through space, while proponents of the Big Bang theory see this as a sign of a receding galaxy. Reber has given many lectures on why he does not believe in the Big Bang theory and many astronomers disagree with him. Reber, however, is accustomed to being alone in his beliefs and is waiting for an opportunity to test them.

What started out as a one-man project in Reber's backyard in Wheaton, Illinois has evolved into the serious science of radio astronomy. For the first decade Reber had been the only radio astronomer. Now the discipline has gained support in the United States, Britain, Australia, and elsewhere. This technology has led to important discoveries in astronomy, especially with respect to quasars and pulsars. It has even become popular among the public. For example, there is now a Society of Radio Astronomers which is an international organization designed to help hundreds of radio astronomy amateurs observe the radio sky. Reber's conviction in his beliefs and his life-long dedication to his profession have increased our knowledge of the universe and have even challenged our beliefs about its conception.

Books

Classics in Radio Astronomy, edited by Woodruff Turner Sullivan III, D. Reidel Publishing Company, 1982.

Hey, J.S., The Evolution of Radio Astronomy, Science History Publications, 1973.

Kraus, John, Big Ear, Cygnus-Quasar Books, 1976.

Kraus, John, Big Ear Two: Listening for Other-Worlds, Cygnus-Quasar Books, 1995.

Kraus, John, Radio Astronomy, Cygnus-Quasar Books, 1986.

Malphrus, Benjamin K., The History of Radio Astronomy and the National Radio Astronomy Observatory: Evolution Toward Big Science, Krieger Publishing Company, 1996.

Tucker, Wallace, and Karen Tucker, The Cosmic Inquirers, Harvard University Press, 1986.

Verschuur, Gerrit L., The Invisible Universe Revealed: The Story of Radio Astronomy, Springer-Verlag, 1987.