An Etymological Dictionary of Astronomy and Astrophysics

The amount of solar radiation in all wavelengths received per unit of time per unit of area on a theoretical surface perpendicular to the Sun’s rays and at Earth’s mean distance from the Sun. Its mean value is 1367.7 W m^-2 or 1.37 × 10⁶ erg sec^-1 cm^-2. In other words, the solar constant is the mean → solar irradiance on the outer atmosphere when the Sun and Earth are spaced at 1 → astronomical unit. See also: → solar luminosity.

See also: → solar; → constant.