Phases of Venus

The full variation of phases of illumination of the planet Venus, first enumerated by Galileo, is considered a crushing blow to the Geocentric Model of the Solar System.In this animation, we see both the variation in the phases of illumination of Venus, from full to crescent, as well as the variation in the apparent size of Venus, from superior conjunction (smallest) to inferior conjunction (largest). This variation in size explains why a less illuminated Venus nevertheless seems much brighter in the evening or morning sky.