Sunspot cycle
The solar cycle (or solar magnetic activity cycle) is the periodic change in the Sun's activity (including changes in the levels of solar radiation and ejection of solar material) and appearance (vis...
Sunspot cycle - Wikipedia
Solar variation
Solar variation is the change in the amount of radiation emitted by the Sun (see Solar radiation) and in its spectral distribution over years to millennia. These variations have periodic components, t...
Solar variation - Wikipedia
Skywave
In radio communication, skywave or skip refers to the propagation of radio waves reflected or refracted back toward Earth from the ionosphere, an electrically charged layer of the upper atmosphere. S...
Skywave - Wikipedia
Milankovitch cycles
Milankovitch theory describes the collective effects of changes in the Earth's movements upon its climate, named after Serbian geophysicist and astronomer Milutin Milanković, who worked on it during h...
Milankovitch cycles - Wikipedia