Venus has the longest day of all the planets in our solar system. A day on Venus, which is the time it takes for the planet to complete one full rotation on its axis, lasts about 243 Earth days. Interestingly, this is longer than a year on Venus, which takes approximately 225 Earth days to orbit the Sun. This unusual phenomenon is due to its slow rotation and retrograde rotation, meaning it rotates in the opposite direction to most planets. As a result, on Venus, the Sun rises in the west and sets in the east.