Venus Day Longer Than Year

On most planets, including our own, a day is a mere fraction of a year. Venus, however, completely upends this familiar rhythm. It takes a sluggish 243 Earth days for the planet to complete a single turn on its axis, but it zips around the Sun in just 225 Earth days. Adding to its strangeness, Venus spins backward, or in retrograde, compared to most other planets in our solar system. If you could stand on its surface, the Sun would appear to rise in the west and set in the east.

Scientists believe this bizarre rotation is a relic of Venus's violent past. One leading theory suggests a massive collision with a planet-sized object early in its history knocked it off-kilter, drastically slowing its spin and even reversing it. Another possibility involves Venus's incredibly thick, heavy atmosphere. Over billions of years, powerful atmospheric tides, created by solar heating, could have acted like a brake, gradually grinding the planet's rotation to its current slow pace.

This unique celestial timing creates a truly alien (Review) experience. Because the planet is orbiting the Sun while it slowly spins backward, a single sunrise-to-sunrise cycle, or a "solar day," is not the full 243 Earth days. Instead, one period of day and night on Venus lasts about 117 Earth days. This means you would experience only about two sunrises and two sunsets during the course of a single Venusian year.