Karl Jansky (1905 - 1950), electrical engineer, and pioneer in the
field of radio astronomy. He was an engineer at Bell Telephone Laboratories
in Holmdel, New Jersey. He was studying how to determine the location of
thunderstorms based their static noise bursts in radio receivers, with
the ultimate goal of developing low-noise, directional receivers for
transoceanic communications. He designed a track-mounted,
vertically-polarized wire antenna grid, to measure the amount
of noise as a function of the antenna's orientation and the time of day.
The antenna was rotated on its circular track once every twenty minutes, and
the total received power measured with a strip chart recorder, 24 hours
While he was able to successfully locate thunderstorms both locally and
worldwide, he also found a daily modulation in the amount of
noise the origin of which he could not immediately determine.
Measurements over a long period of time determined that the source of the
noise was not only extraterrestrial, but extra-solar, coming instead from
the center of the Milky Way Galaxy, which he detected at 10 (30 MHz)
and 14.6 meters (20.6 MHz). He published this work in three papers
in the Proceedings of the Institute of Radio Engineers (later to become
the IEEE) in December 1932 (v. 20, p. 1920), October 1933 (v. 21, p. 1387),
and October 1935 (v. 23, p. 1158). Unfortunately, the significance of this
work was not immediately recognized, and radio astronomy did not come into its
own until the work of fellow radio engineer Grote Reber in the early 1940s.
His plans for building a truly directional, parabolic dish and receiver
weren't pursued by Bell Labs, and he was transferred to other projects within
Jansky died prematurely of a stroke at the age of 45.
He has been honored by having a unit of measurement - the Jansky - named for
him. The American Astronomical Society and NRAO also bestow the Jansky
award for outstanding achievements in the field of astronomy, and NRAO also
awards several Jansky Fellowships to outstanding postdoctoral researchers in
the field of radio astronomy.
Sources: various, including Radio Astronomy by J. D. Kraus (Powell, Ohio:
Cygnus-Quasar Books, 1986)