Kennelly–Heaviside layer

During the daytime the solar wind presses this layer closer to the Earth, thereby limiting how far it can reflect radio waves.

Conversely, on the night (lee) side of the Earth, the solar wind drags the ionosphere further away, thereby greatly increasing the range which radio waves can travel by reflection.

Existence of a reflective layer was predicted in 1902 independently and almost simultaneously by the American electrical engineer Arthur Edwin Kennelly (1861–1939)[5] and the British polymath Oliver Heaviside (1850–1925), as an explanation for the propagation of radio waves beyond the horizon observed by Guglielmo Marconi in 1901.

Nevertheless, Marconi had received signals in Newfoundland that were broadcast in England, so clearly there must be some mechanism allowing the transmission to reach that far.

The ITU standard model of absorption and reflection of radio waves by the Heaviside Layer was developed by the British Ionospheric physicist Louis Muggleton[8] in the 1970s.