Jansky
Jansky, Karl Guthe
ACHIEVEMENTS: Cosmic radio waves
DATE AND PLACE OF BIRTH:
22 October 1905, Norman, OK
DATE AND PLACE OF DEATH AND AGE AT DEATH:
14 February 1950, Red Bank, NJ. Aged 45
DISCIPLINE: Electrical Engineer
FIELD: Communications
LANGUAGE: English
EDUCATION: University of Wisconsin
MAJOR WORK: "Directional Studies of Atmospherics at High Frequencies" (1932, in "Proceedings of the Institute of Radio Engineers")
LIFE AND TIMES:
Jansky's father was a professor of electrical engineering at Wisconsin and Janksy showed an early interest in electronics. As a child, he built a crystal radio. He qualified with a physics degree in 1927 and in 1928 joined Bell Telephone Labs where he was assigned to their radio research division at Cliffwood, New Jersey.
The first job he was given was to identify the sources of the static which interfered with trans-oceanic radiotelephone communications. Jansky's particular brief was to pinpoint the static source. He designed a very large rotating antenna and took twenty-four hour recordings. Bell Labs moved their radio division to Holmdel and by the middle of 1931 he had observed that the static hiss had a regular maximum period once every twenty-four hours. He thought at first that it related the sun, but then found that it was moving away from the sun. He was able to correlate episodic highs with thunder storms but the source of the daily maximum static remained unclear. Within six months, however, Jansky had come to a startling conclusion: that the noise had an extra-terrestial origin. He was also sure that it originated at a fixed point in space which moved across the sky each day as the Earth rotated.
By April 1932, he had convinced his superior and obtained permission to write up his findings, although he was advised to adopt a conservative tone. His article appeared in the "Proceedings of the Institute of Radio Engineers" under the title "Directional Studies of Atmospherics at High Frequencies." Jansky had made a major discovery which would lead to the development of radio astronomy and major advances in astrophysics and knowledge of the universe, but nobody appeared to see its possibilities and he was not contacted by the astronomical community. Almost the only person who got excited was Reber*, then an enthusiastic amateur astronomer, who tried to pick up interstellar radio waves on his short-wave radio receiver.
In 1933 Janksy wrote two papers for "PIRE" in which he suggested that the static appeared to come from somewhere near the center of the Milky Way galaxy. In the same year he published a paper in "Popular Astronomy" which caused some reaction from a small number of astronomers who discussed the origins of intergalactic radio energy.
The financial depression occurring at the time in the US forced staff cutbacks at Bell, and Jansky became involved in other projects. After 1936 he took no more observations and worked for the company on improvements in radiotelephony and on man-made sources of radio noise. During World War II (1939-1945) he was given a citation for his research on radio direction-finding which was of vital importance in radar detection. Jansky had never been physically fit and his health declined rapidly after 1945.
ASSESSMENT: Jansky is often referred to as the founder of radio astronomy.
EXTRA CONNECTIONS:
His work followed that of Marconi*
His discoveries influenced the work of Penzias* & Wilson* and that of Jodrell Bank*
ONELINER: Karl Jansky, discoverer of cosmic radio-wave emissions
BIBLIOGRAPHY:
ANB, EB
See Wikipedia below
PARENTS:
Father: Cyril Methodius Jansky
Mother: Nellie Moreau
SIBLINGS:
Brother: C Moreau Jansky
SPOUSE: Alice La Rue Knapp
CHILDREN:2
Karl Guthe Jansky (October 22, 1905 – February 14, 1950) was an American physicist and radio engineer who in August 1931 first discovered radio waves emanating from the Milky Way. He is considered one of the founding figures of radio astronomy.[1]
Contents
- 1 Early life
- 2 Radio astronomy
- 3 Follow-up
- 4 Legacy
- 5 Selected writings
- 6 See also
- 7 References
- 8 External links
Early life
Karl Guthe Jansky was born in what was then the Territory of Oklahoma where his father, Cyril M. Jansky, was Dean of the College of Engineering at the University of Oklahoma at Norman. Cyril M. Jansky, born in Wisconsin of Czech immigrants, had started teaching at the age of sixteen. He was a teacher throughout his active life, retiring as Professor of Electrical Engineering at the University of Wisconsin. He was an engineer with a strong interest in physics, a trait passed on to his sons. Karl Jansky was named after Dr. Karl Guthe, who had been an important mentor to Cyril M. Jansky.
Karl Jansky's mother, born Nellie Moreau, was of French and English descent. Karl's brother Cyril Jansky Jr., who was ten years older, helped build some of the earliest radio transmitters in the country, including 9XM in Wisconsin (now WHA of Wisconsin Public Radio) and 9XI in Minnesota (now KUOM).[2]
Karl Jansky attended college at the University of Wisconsin–Madison where he received his BS in physics in 1927. In 1928 he joined the Bell Telephone Laboratories site in Holmdel, New Jersey. Bell Labs wanted to investigate atmospheric and ionospheric properties using "short waves" (wavelengths of about 10–20 meters) for use in transatlantic radio telephone service. As a radio engineer, Jansky was assigned the job of investigating sources of static that might interfere with radio voice transmissions.
Radio astronomy
At Bell Telephone Laboratories Jansky built anantenna designed to receive radio waves at a frequency of 20.5 MHz (wavelength about 14.6 meters). It was mounted on a turntable that allowed it to be rotated in any direction, earning it the name "Jansky's merry-go-round". It had a diameter of approximately 100 ft. and stood 20 ft. tall. By rotating the antenna on a set of four Ford Model-T tires, the direction of a received signal could be pinpointed. A small shed to the side of the antenna housed an analog pen-and-paper recording system.
After recording signals from all directions for several months, Jansky eventually categorized them into three types of static: nearby thunderstorms, distant thunderstorms, and a faint steady hiss of unknown origin. He spent over a year investigating the source of the third type of static. The location of maximum intensity rose and fell once a day, leading Jansky to initially surmise that he was detecting radiation from the Sun.
After a few months of following the signal, however, the brightest point moved away from the position of the Sun. Jansky also determined that the signal repeated on a cycle of 23 hours and 56 minutes, the period of the Earth's rotation relative to the stars (sidereal day), instead of relative to the sun (solar day). By comparing his observations with optical astronomical maps, Jansky concluded that the radiation was coming from the Milky Way and was strongest in the direction of the center of the galaxy, in theconstellation of Sagittarius.
His discovery was widely publicized, appearing in the New York Times of May 5, 1933.[3] He published his classic paper "Electrical disturbances apparently of extraterrestrial origin" in Proc. IRE in 1933. This paper was re-printed in Proc. IEEE in 1984 (for their centennial issue, where they note the research most likely would have won a Nobel prize, had not the author died young) and again in 1998, for the first centennial of radio. Jansky wanted to follow up on this discovery and investigate the radio waves from the Milky Way in further detail. He submitted a proposal to Bell Labs to build a 30 meter diameter dish antenna with greater sensitivity that would allow more careful measurements of the structure and strength of the radio emission. Bell Labs, however, rejected his request for funding on the grounds that the detected emission would not significantly affect their planned transatlantic communications system. Jansky was re-assigned to another project and did no further work in the field of astronomy.
Follow-up
Several scientists were interested in Jansky's discovery, but radio astronomy remained a dormant field for several years, due in part to Jansky's lack of formal training as an astronomer. His discovery had come in the midst of the Great Depression, and observatories were wary of taking on any new and potentially risky projects.
Two men who learned of Jansky's 1933 discovery were of great influence on the later development of the new study of radio astronomy: one was Grote Reber, a radio engineer who singlehandedly built a radio telescope in his Illinois back yard in 1937 and did the first systematic survey of astronomical radio waves. The second was Prof. John D. Kraus, who, after World War II, started a radio observatory at Ohio State University and wrote a textbook on radio astronomy, long considered a standard by radio astronomers.
Legacy
A full-scale replica of Jansky's original rotating telescope is located on the grounds of the NRAO site (38°25′53.9″N 79°48′58.5″W) in Green Bank, West Virginia, near a reconstructed version of Grote Reber's 9-meter dish.In honor of Jansky, the unit used by radio astronomers for the strength (or flux density) of radio sources is the jansky (1 Jy = 10−26 W m−2 Hz−1). The crater Jansky on the Moon is also named after him. The NRAO postdoctoral fellowship program is named after Karl Jansky.[4] Additionally, NRAO awards the Jansky Prize annually in Jansky's honor.[5] On January 10, 2012, the NRAO announced the Very Large Array (VLA), the radio telescope in Magdalena, New Mexico, would be renamed the Karl G. Jansky Very Large Array in honor of Karl Janksy's contribution to Radio Astronomy.[6]
The original site of Jansky's antenna (40°21′54.5″N 74°09′48.9″W) at what is now the vacant Bell Labs Holmdel Complex at 101 Crawfords Corner Road, Holmdel, New Jersey, was determined by Tony Tyson and Robert Wilson of Lucent Technologies (the successor of Bell Telephone Laboratories) in 1998, and a monument and plaque were placed there to honor the achievement.[7] The monument is a stylized sculpture of the antenna and is oriented as Jansky's antenna was at 7:10 p.m. on September 16, 1932, at a moment of maximum signal caused by alignment with the center of our galaxy in the direction of the constellation Sagittarius.[8]
Jansky noise is named after Jansky, and refers to high frequency static disturbances of cosmic origin.
Jansky was a resident of Little Silver, New Jersey, and died at age 44 in a Red Bank, New Jersey, hospital (now called Riverview Medical Center) due to a heart condition.[9]
Extra Connections: Bell Labs built a facility in Holmdell (Bruce Springsteen recorded Darkness on the Edge of Town in an old farmhouse there), fifteen miles west of the Jersey Shore, with a giant water tower in the shape of a transistor and a huge neofuturistic building called the world's largest mirror designed by Saarinen, who worked for the OSS in WWII, and helped design the Situation Room in the White House. He also designed the great arch in St. Louis, the gateway to Western expansion/Manifest Destiny, initially the site of the Spanish capital of Louisiana (New Spain). The memorial to Jefferson was originally conceived as an FDR WPA project during the Great Depression, but delayed by WWII, and is the tallest memorial in the United States, and the tallest stainless steel monument in the world. Workers had to spray firehoses on one leg to counteract thermal expansion so the last pieces could be installed at the top. The base of each leg at ground level had to have an engineering tolerance of 1⁄64 inch (0.40 mm) or the two legs would not meet at the top. Civil rights activists were arrested after they climbed up 125 feet to protest discrimination against African-American workers. Vice President Hubert Humphey declared at the dedication that it brings a "new purpose" and a "new sense of urgency to wipe out every slum." "Whatever is shoddy, whatever is ugly, whatever is waste, whatever is false, will be measured and condemned" in comparison to the Gateway Arch.
In the 1964 New York World's Fair:
IBM Pavilion
The IBM Corporation had a popular pavilion, where a giant 500-seat grandstand called the "People Wall" was pushed by hydraulic rams high up into an ellipsoidal theater designed by Eero Saarinen. There, a film by Charles and Ray Eames titled Think was shown on fourteen large and eight small screens, illuminating the workings of computer logic. At ground level beneath the theater, visitors could explore Mathematica: A World of Numbers... and Beyond (an exhibit of mathematical models and curiosities) and view the Mathematics Peep Show (a series of short films illustrating basic mathematical concepts).[44] IBM also demonstrated handwriting recognition on a mainframe computer that would look up what happened on a particular date that a person wrote down—for many visitors, this was their first hands-on interaction with a computer.
Bell System Pavilion
The Bell System (prior to its break up into regional companies) hosted a 15-minute ride in moving armchairs depicting the history of communications in dioramas and film. Other Bell exhibits included thePicturephone as well as a demonstration of the computer modem. DuPont presented a musical review by composer Michael Brown called "The Wonderful World of Chemistry". At Parker Pen's exhibit, a computer would make a match to an international penpal.