Worlds of David Darling
Encyclopedia of Science
Home > Encyclopedia of Science

solar constant

The rate at which solar energy, at all wavelengths, is received per unit area at the top level of Earth's atmosphere. The solar constant actually varies by about 0.3% over the 11-year solar cycle but averages about 1,368 W/m2. Each planet has its own planetary solar constant, ranging from Mercury (9936.9 W/m2) to Pluto (0.87 W/m2).

Related category