Venus Rotates Backwards

While nearly every other major body in our solar system spins counter-clockwise, Venus moves to its own rhythm. This "retrograde rotation" is so extreme that if you could stand on its surface, you would witness the Sun make a slow journey up from the western horizon and down into the eastern one. The planet's spin is also incredibly sluggish. A single Venusian day lasts 243 Earth days, which is longer than its entire year of about 225 Earth days. This means that on Venus, a day is literally longer than a year, making it one of the most bizarre rotational dynamics in our cosmic neighborhood.

Scientists are not entirely certain why Venus is the solar system's odd one out, but two leading theories prevail. The first, more dramatic explanation suggests that early in its history, Venus was struck by a massive planet-sized object that sent it spinning in the opposite direction. A more recent and widely considered theory points to its incredibly thick, heavy atmosphere. Over billions of years, powerful atmospheric tides, created by solar heating, could have generated enough friction with the planet's surface to slow its original rotation to a halt and then slowly reverse it, leaving us with the backward-spinning world we observe today.