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Karl Jansky

1905–1950 · Radio astronomy, engineering, physics
American radio engineer and founder of radio astronomy. His accidental discovery of cosmic radio emission in 1931 gave rise to a new way of exploring the Universe.

Biography

Born in 1905 in Norman, Oklahoma. He studied at the University of Wisconsin, earning a bachelor's degree in physics. He worked at Bell Telephone Laboratories, where he was tasked with investigating sources of radio interference. In the course of this work, he discovered a steady signal from the center of the Galaxy. Due to the priority of engineering over science at Bell Labs, he was not allowed to develop the discovery further, and he died young in 1950 without receiving widespread recognition. The unit of spectral flux density is named in his honor.

Key discoveries

💡 Jansky discovered cosmic radio emission while trying to find sources of noise for transatlantic radio communication. He built a rotating antenna, dubbed 'Jansky's merry-go-round', and initially thought he was hearing interference from cars, then from the Sun, until he realized the source moved with sidereal time.
Quote: "I could not believe that these signals came from beyond Earth, but all evidence indicated that their source is at the center of our Galaxy."
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Related tags
cosmic microwave background
Related scientists
Ralph AlpherWilhelm WienLudwig BoltzmannRobert Woodrow WilsonRainer SachsRobert H. DickeJames PeeblesAndrei Linde

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