The Inverse-Square Law The equation for the inverse-square law is shown below Eq (1). E*2= E*1 (R₁ / R₂)² . Eq (1) Where E*2 is the irradiance at the distance of interest, E*, is the emission from an emitter (for example, the Sun) or at a reference location (for example, at the orbital distance of a planet), R₁ is the radius of the emitter, and R₂ is the distance to the location of interest in meters. Here are some values for the Sun. Note that the following only applies to the Sun, not other objects. E*1 = 62,930,000 W/m² R₁ 695,700,000 m = The nearby Sun-like star Tau Ceti has an estimated radius of 0.793 (79.3%) that of the Sun and a total emission of 46,243,304 W/m². How much irradiance would a planet located around Fomalhaut receive, assuming this world has the same mean orbital distance as the Earth, 149,597,870,700 m?