Edward Victor Appleton

Edward Victor Appleton was a British physicist who demonstrated the existence of a high-altitude ionized atmospheric layer through radio experiments. He received the 1947 Nobel Prize in Physics for this work.

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Appleton layer: A region of the ionosphere, now called the F region, that reflects radio waves and supports long-distance communication. Appleton’s measurements established this upper ionospheric region as a distinct layer.
Oliver Heaviside: An English mathematician and physicist who predicted an electrically conducting upper-atmospheric layer. His prediction helped frame the question Appleton tested experimentally.
Nobel Prize in Physics: An annual international award recognizing major contributions to physics. Appleton received the 1947 prize for investigations of the upper atmosphere.
Skywave: A radio wave that reaches distant locations after reflection or refraction in the ionosphere. Appleton’s work explained the atmospheric return paths that make skywave communication possible.
Ionosphere: The region of Earth’s upper atmosphere containing enough ions and free electrons to affect radio-wave propagation. The Appleton layer is a part of this electrically charged atmospheric region.
Arthur E. Kennelly: An American electrical engineer who independently proposed an ionized atmospheric layer that could reflect radio waves. His proposal, alongside Heaviside’s, preceded Appleton’s experimental confirmation.
Cavendish Laboratory: A physics laboratory at the University of Cambridge, founded in 1874. Appleton conducted influential radio research during his Cambridge career.
Shortwave radio: Radio communication using frequencies that can travel beyond the horizon through ionospheric propagation. Understanding ionospheric layers improved the prediction of shortwave signal paths.
Radio wave propagation: The transmission of radio-frequency electromagnetic waves through space and matter. Appleton used changes in received radio signals to infer atmospheric structure.
Marconi transatlantic radio transmission: Guglielmo Marconi’s 1901 reception of a radio signal sent across the Atlantic Ocean. The transmission raised questions about how radio waves travel beyond the horizon.