Fun fact: the gravitational attraction between two bodies is inversely proportional to the square of the distance between them. But so is the relationship between light intensity and distance to the light source. So if you’re all up in someone’s face with a flash and said face turns white, and you want to halve the light, you don’t need to double the distance between subject and flash, you need to increase it by a factor of 1.4 (the square root of 2). And Mercury, which is at approximately 1/3 AU—the Astronomical Unit, which is the mean distance between the Earth and the Sun—receives roughly nine times as much radiation from the Sun as we do on Earth.
dailymeh posted this on August 31, 2011
